From c9125603a535f82cc9a53f47533f0a3d174e7008 Mon Sep 17 00:00:00 2001 From: Rebecca Turner Date: Mon, 18 Dec 2023 10:34:19 -0800 Subject: [PATCH 1/3] Unindent `print.hh` declarations --- src/libexpr/print.hh | 82 +++++++++++++++++++++++--------------------- 1 file changed, 42 insertions(+), 40 deletions(-) diff --git a/src/libexpr/print.hh b/src/libexpr/print.hh index 3b72ae201..abf830864 100644 --- a/src/libexpr/print.hh +++ b/src/libexpr/print.hh @@ -10,45 +10,47 @@ #include namespace nix { - /** - * Print a string as a Nix string literal. - * - * Quotes and fairly minimal escaping are added. - * - * @param s The logical string - */ - std::ostream & printLiteralString(std::ostream & o, std::string_view s); - inline std::ostream & printLiteralString(std::ostream & o, const char * s) { - return printLiteralString(o, std::string_view(s)); - } - inline std::ostream & printLiteralString(std::ostream & o, const std::string & s) { - return printLiteralString(o, std::string_view(s)); - } - /** Print `true` or `false`. */ - std::ostream & printLiteralBool(std::ostream & o, bool b); - - /** - * Print a string as an attribute name in the Nix expression language syntax. - * - * Prints a quoted string if necessary. - */ - std::ostream & printAttributeName(std::ostream & o, std::string_view s); - - /** - * Returns `true' is a string is a reserved keyword which requires quotation - * when printing attribute set field names. - */ - bool isReservedKeyword(const std::string_view str); - - /** - * Print a string as an identifier in the Nix expression language syntax. - * - * FIXME: "identifier" is ambiguous. Identifiers do not have a single - * textual representation. They can be used in variable references, - * let bindings, left-hand sides or attribute names in a select - * expression, or something else entirely, like JSON. Use one of the - * `print*` functions instead. - */ - std::ostream & printIdentifier(std::ostream & o, std::string_view s); +/** + * Print a string as a Nix string literal. + * + * Quotes and fairly minimal escaping are added. + * + * @param s The logical string + */ +std::ostream & printLiteralString(std::ostream & o, std::string_view s); +inline std::ostream & printLiteralString(std::ostream & o, const char * s) { + return printLiteralString(o, std::string_view(s)); +} +inline std::ostream & printLiteralString(std::ostream & o, const std::string & s) { + return printLiteralString(o, std::string_view(s)); +} + +/** Print `true` or `false`. */ +std::ostream & printLiteralBool(std::ostream & o, bool b); + +/** + * Print a string as an attribute name in the Nix expression language syntax. + * + * Prints a quoted string if necessary. + */ +std::ostream & printAttributeName(std::ostream & o, std::string_view s); + +/** + * Returns `true' is a string is a reserved keyword which requires quotation + * when printing attribute set field names. + */ +bool isReservedKeyword(const std::string_view str); + +/** + * Print a string as an identifier in the Nix expression language syntax. + * + * FIXME: "identifier" is ambiguous. Identifiers do not have a single + * textual representation. They can be used in variable references, + * let bindings, left-hand sides or attribute names in a select + * expression, or something else entirely, like JSON. Use one of the + * `print*` functions instead. + */ +std::ostream & printIdentifier(std::ostream & o, std::string_view s); + } From 0fa08b451682fb3311fe58112ff05c4fe5bee3a4 Mon Sep 17 00:00:00 2001 From: Rebecca Turner Date: Tue, 12 Dec 2023 13:57:36 -0800 Subject: [PATCH 2/3] Unify and refactor value printing Previously, there were two mostly-identical value printers -- one in `libexpr/eval.cc` (which didn't force values) and one in `libcmd/repl.cc` (which did force values and also printed ANSI color codes). This PR unifies both of these printers into `print.cc` and provides a `PrintOptions` struct for controlling the output, which allows for toggling whether values are forced, whether repeated values are tracked, and whether ANSI color codes are displayed. Additionally, `PrintOptions` allows tuning the maximum number of attributes, list items, and bytes in a string that will be displayed; this makes it ideal for contexts where printing too much output (e.g. all of Nixpkgs) is distracting. (As requested by @roberth in https://github.com/NixOS/nix/pull/9554#issuecomment-1845095735) Please read the tests for example output. Future work: - It would be nice to provide this function as a builtin, perhaps `builtins.toStringDebug` -- a printing function that never fails would be useful when debugging Nix code. - It would be nice to support customizing `PrintOptions` members on the command line, e.g. `--option to-string-max-attrs 1000`. --- src/libcmd/repl.cc | 158 +---- src/libexpr/eval.cc | 126 +--- src/libexpr/eval.hh | 4 +- src/libexpr/print-options.hh | 52 ++ src/libexpr/print.cc | 416 +++++++++++- src/libexpr/print.hh | 6 + src/libexpr/value.hh | 17 +- src/libutil/english.cc | 18 + src/libutil/english.hh | 18 + src/nix-env/user-env.cc | 5 +- src/nix-instantiate/nix-instantiate.cc | 2 +- tests/functional/lang/eval-okay-print.err.exp | 2 +- tests/functional/lang/eval-okay-print.exp | 2 +- .../lang/eval-okay-repeated-empty-attrs.exp | 1 + .../lang/eval-okay-repeated-empty-attrs.nix | 2 + .../lang/eval-okay-repeated-empty-list.exp | 1 + .../lang/eval-okay-repeated-empty-list.nix | 1 + tests/unit/libexpr/value/print.cc | 621 +++++++++++++++++- 18 files changed, 1174 insertions(+), 278 deletions(-) create mode 100644 src/libexpr/print-options.hh create mode 100644 src/libutil/english.cc create mode 100644 src/libutil/english.hh create mode 100644 tests/functional/lang/eval-okay-repeated-empty-attrs.exp create mode 100644 tests/functional/lang/eval-okay-repeated-empty-attrs.nix create mode 100644 tests/functional/lang/eval-okay-repeated-empty-list.exp create mode 100644 tests/functional/lang/eval-okay-repeated-empty-list.nix diff --git a/src/libcmd/repl.cc b/src/libcmd/repl.cc index 7a1df74ef..72e3559df 100644 --- a/src/libcmd/repl.cc +++ b/src/libcmd/repl.cc @@ -93,9 +93,17 @@ struct NixRepl void evalString(std::string s, Value & v); void loadDebugTraceEnv(DebugTrace & dt); - typedef std::set ValuesSeen; - std::ostream & printValue(std::ostream & str, Value & v, unsigned int maxDepth); - std::ostream & printValue(std::ostream & str, Value & v, unsigned int maxDepth, ValuesSeen & seen); + void printValue(std::ostream & str, + Value & v, + unsigned int maxDepth = std::numeric_limits::max()) + { + ::nix::printValue(*state, str, v, PrintOptions { + .ansiColors = true, + .force = true, + .derivationPaths = true, + .maxDepth = maxDepth + }); + } }; std::string removeWhitespace(std::string s) @@ -708,7 +716,8 @@ bool NixRepl::processLine(std::string line) else if (command == ":p" || command == ":print") { Value v; evalString(arg, v); - printValue(std::cout, v, 1000000000) << std::endl; + printValue(std::cout, v); + std::cout << std::endl; } else if (command == ":q" || command == ":quit") { @@ -770,7 +779,8 @@ bool NixRepl::processLine(std::string line) } else { Value v; evalString(line, v); - printValue(std::cout, v, 1) << std::endl; + printValue(std::cout, v, 1); + std::cout << std::endl; } } @@ -892,144 +902,6 @@ void NixRepl::evalString(std::string s, Value & v) } -std::ostream & NixRepl::printValue(std::ostream & str, Value & v, unsigned int maxDepth) -{ - ValuesSeen seen; - return printValue(str, v, maxDepth, seen); -} - - - - -// FIXME: lot of cut&paste from Nix's eval.cc. -std::ostream & NixRepl::printValue(std::ostream & str, Value & v, unsigned int maxDepth, ValuesSeen & seen) -{ - str.flush(); - checkInterrupt(); - - state->forceValue(v, v.determinePos(noPos)); - - switch (v.type()) { - - case nInt: - str << ANSI_CYAN << v.integer << ANSI_NORMAL; - break; - - case nBool: - str << ANSI_CYAN; - printLiteralBool(str, v.boolean); - str << ANSI_NORMAL; - break; - - case nString: - str << ANSI_WARNING; - printLiteralString(str, v.string_view()); - str << ANSI_NORMAL; - break; - - case nPath: - str << ANSI_GREEN << v.path().to_string() << ANSI_NORMAL; // !!! escaping? - break; - - case nNull: - str << ANSI_CYAN "null" ANSI_NORMAL; - break; - - case nAttrs: { - seen.insert(&v); - - bool isDrv = state->isDerivation(v); - - if (isDrv) { - str << "«derivation "; - Bindings::iterator i = v.attrs->find(state->sDrvPath); - NixStringContext context; - if (i != v.attrs->end()) - str << state->store->printStorePath(state->coerceToStorePath(i->pos, *i->value, context, "while evaluating the drvPath of a derivation")); - else - str << "???"; - str << "»"; - } - - else if (maxDepth > 0) { - str << "{ "; - - typedef std::map Sorted; - Sorted sorted; - for (auto & i : *v.attrs) - sorted.emplace(state->symbols[i.name], i.value); - - for (auto & i : sorted) { - printAttributeName(str, i.first); - str << " = "; - if (seen.count(i.second)) - str << "«repeated»"; - else - try { - printValue(str, *i.second, maxDepth - 1, seen); - } catch (AssertionError & e) { - str << ANSI_RED "«error: " << e.msg() << "»" ANSI_NORMAL; - } - str << "; "; - } - - str << "}"; - } else - str << "{ ... }"; - - break; - } - - case nList: - seen.insert(&v); - - str << "[ "; - if (maxDepth > 0) - for (auto elem : v.listItems()) { - if (seen.count(elem)) - str << "«repeated»"; - else - try { - printValue(str, *elem, maxDepth - 1, seen); - } catch (AssertionError & e) { - str << ANSI_RED "«error: " << e.msg() << "»" ANSI_NORMAL; - } - str << " "; - } - else - str << "... "; - str << "]"; - break; - - case nFunction: - if (v.isLambda()) { - std::ostringstream s; - s << state->positions[v.lambda.fun->pos]; - str << ANSI_BLUE "«lambda @ " << filterANSIEscapes(s.str()) << "»" ANSI_NORMAL; - } else if (v.isPrimOp()) { - str << ANSI_MAGENTA "«primop»" ANSI_NORMAL; - } else if (v.isPrimOpApp()) { - str << ANSI_BLUE "«primop-app»" ANSI_NORMAL; - } else { - abort(); - } - break; - - case nFloat: - str << v.fpoint; - break; - - case nThunk: - case nExternal: - default: - str << ANSI_RED "«unknown»" ANSI_NORMAL; - break; - } - - return str; -} - - std::unique_ptr AbstractNixRepl::create( const SearchPath & searchPath, nix::ref store, ref state, std::function getValues) diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc index d408f1adc..0659a2173 100644 --- a/src/libexpr/eval.cc +++ b/src/libexpr/eval.cc @@ -105,117 +105,23 @@ RootValue allocRootValue(Value * v) #endif } -void Value::print(const SymbolTable &symbols, std::ostream &str, - std::set *seen, int depth) const - -{ - checkInterrupt(); - - if (depth <= 0) { - str << "«too deep»"; - return; - } - switch (internalType) { - case tInt: - str << integer; - break; - case tBool: - printLiteralBool(str, boolean); - break; - case tString: - printLiteralString(str, string_view()); - break; - case tPath: - str << path().to_string(); // !!! escaping? - break; - case tNull: - str << "null"; - break; - case tAttrs: { - if (seen && !attrs->empty() && !seen->insert(attrs).second) - str << "«repeated»"; - else { - str << "{ "; - for (auto & i : attrs->lexicographicOrder(symbols)) { - str << symbols[i->name] << " = "; - i->value->print(symbols, str, seen, depth - 1); - str << "; "; - } - str << "}"; - } - break; - } - case tList1: - case tList2: - case tListN: - if (seen && listSize() && !seen->insert(listElems()).second) - str << "«repeated»"; - else { - str << "[ "; - for (auto v2 : listItems()) { - if (v2) - v2->print(symbols, str, seen, depth - 1); - else - str << "(nullptr)"; - str << " "; - } - str << "]"; - } - break; - case tThunk: - case tApp: - if (!isBlackhole()) { - str << ""; - } else { - // Although we know for sure that it's going to be an infinite recursion - // when this value is accessed _in the current context_, it's likely - // that the user will misinterpret a simpler «infinite recursion» output - // as a definitive statement about the value, while in fact it may be - // a valid value after `builtins.trace` and perhaps some other steps - // have completed. - str << "«potential infinite recursion»"; - } - break; - case tLambda: - str << ""; - break; - case tPrimOp: - str << ""; - break; - case tPrimOpApp: - str << ""; - break; - case tExternal: - str << *external; - break; - case tFloat: - str << fpoint; - break; - default: - printError("Nix evaluator internal error: Value::print(): invalid value type %1%", internalType); - abort(); - } -} - -void Value::print(const SymbolTable &symbols, std::ostream &str, - bool showRepeated, int depth) const { - std::set seen; - print(symbols, str, showRepeated ? nullptr : &seen, depth); -} - // Pretty print types for assertion errors std::ostream & operator << (std::ostream & os, const ValueType t) { os << showType(t); return os; } -std::string printValue(const EvalState & state, const Value & v) +std::string printValue(EvalState & state, Value & v) { std::ostringstream out; - v.print(state.symbols, out); + v.print(state, out); return out.str(); } +void Value::print(EvalState & state, std::ostream & str, PrintOptions options) +{ + printValue(state, str, *this, options); +} const Value * getPrimOp(const Value &v) { const Value * primOp = &v; @@ -710,6 +616,26 @@ void PrimOp::check() } +std::ostream & operator<<(std::ostream & output, PrimOp & primOp) +{ + output << "primop " << primOp.name; + return output; +} + + +PrimOp * Value::primOpAppPrimOp() const +{ + Value * left = primOpApp.left; + while (left && !left->isPrimOp()) { + left = left->primOpApp.left; + } + + if (!left) + return nullptr; + return left->primOp; +} + + void Value::mkPrimOp(PrimOp * p) { p->check(); diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh index 5e0f1886d..9141156b1 100644 --- a/src/libexpr/eval.hh +++ b/src/libexpr/eval.hh @@ -84,6 +84,8 @@ struct PrimOp void check(); }; +std::ostream & operator<<(std::ostream & output, PrimOp & primOp); + /** * Info about a constant */ @@ -127,7 +129,7 @@ std::unique_ptr mapStaticEnvBindings(const SymbolTable & st, const Stati void copyContext(const Value & v, NixStringContext & context); -std::string printValue(const EvalState & state, const Value & v); +std::string printValue(EvalState & state, Value & v); std::ostream & operator << (std::ostream & os, const ValueType t); diff --git a/src/libexpr/print-options.hh b/src/libexpr/print-options.hh new file mode 100644 index 000000000..11ff9ae87 --- /dev/null +++ b/src/libexpr/print-options.hh @@ -0,0 +1,52 @@ +#pragma once +/** + * @file + * @brief Options for printing Nix values. + */ + +#include + +namespace nix { + +/** + * Options for printing Nix values. + */ +struct PrintOptions +{ + /** + * If true, output ANSI color sequences. + */ + bool ansiColors = false; + /** + * If true, force values. + */ + bool force = false; + /** + * If true and `force` is set, print derivations as + * `«derivation /nix/store/...»` instead of as attribute sets. + */ + bool derivationPaths = false; + /** + * If true, track which values have been printed and skip them on + * subsequent encounters. Useful for self-referential values. + */ + bool trackRepeated = true; + /** + * Maximum depth to evaluate to. + */ + size_t maxDepth = std::numeric_limits::max(); + /** + * Maximum number of attributes in an attribute set to print. + */ + size_t maxAttrs = std::numeric_limits::max(); + /** + * Maximum number of list items to print. + */ + size_t maxListItems = std::numeric_limits::max(); + /** + * Maximum string length to print. + */ + size_t maxStringLength = std::numeric_limits::max(); +}; + +} diff --git a/src/libexpr/print.cc b/src/libexpr/print.cc index 53ba70bdd..db26ed4c2 100644 --- a/src/libexpr/print.cc +++ b/src/libexpr/print.cc @@ -1,24 +1,66 @@ -#include "print.hh" +#include #include +#include "print.hh" +#include "ansicolor.hh" +#include "signals.hh" +#include "store-api.hh" +#include "terminal.hh" +#include "english.hh" + namespace nix { -std::ostream & -printLiteralString(std::ostream & str, const std::string_view string) +void printElided( + std::ostream & output, + unsigned int value, + const std::string_view single, + const std::string_view plural, + bool ansiColors) { + if (ansiColors) + output << ANSI_FAINT; + output << " «"; + pluralize(output, value, single, plural); + output << " elided»"; + if (ansiColors) + output << ANSI_NORMAL; +} + + +std::ostream & +printLiteralString(std::ostream & str, const std::string_view string, size_t maxLength, bool ansiColors) +{ + size_t charsPrinted = 0; + if (ansiColors) + str << ANSI_MAGENTA; str << "\""; for (auto i = string.begin(); i != string.end(); ++i) { + if (charsPrinted >= maxLength) { + str << "\""; + printElided(str, string.length() - charsPrinted, "byte", "bytes", ansiColors); + return str; + } + if (*i == '\"' || *i == '\\') str << "\\" << *i; else if (*i == '\n') str << "\\n"; else if (*i == '\r') str << "\\r"; else if (*i == '\t') str << "\\t"; else if (*i == '$' && *(i+1) == '{') str << "\\" << *i; else str << *i; + charsPrinted++; } str << "\""; + if (ansiColors) + str << ANSI_NORMAL; return str; } +std::ostream & +printLiteralString(std::ostream & str, const std::string_view string) +{ + return printLiteralString(str, string, std::numeric_limits::max(), false); +} + std::ostream & printLiteralBool(std::ostream & str, bool boolean) { @@ -90,5 +132,373 @@ printAttributeName(std::ostream & str, std::string_view name) { return str; } +bool isImportantAttrName(const std::string& attrName) +{ + return attrName == "type" || attrName == "_type"; +} + +typedef std::pair AttrPair; + +struct ImportantFirstAttrNameCmp +{ + + bool operator()(const AttrPair& lhs, const AttrPair& rhs) const + { + auto lhsIsImportant = isImportantAttrName(lhs.first); + auto rhsIsImportant = isImportantAttrName(rhs.first); + return std::forward_as_tuple(!lhsIsImportant, lhs.first) + < std::forward_as_tuple(!rhsIsImportant, rhs.first); + } +}; + +typedef std::set ValuesSeen; + +class Printer +{ +private: + std::ostream & output; + EvalState & state; + PrintOptions options; + std::optional seen; + + void printRepeated() + { + if (options.ansiColors) + output << ANSI_MAGENTA; + output << "«repeated»"; + if (options.ansiColors) + output << ANSI_NORMAL; + } + + void printNullptr() + { + if (options.ansiColors) + output << ANSI_MAGENTA; + output << "«nullptr»"; + if (options.ansiColors) + output << ANSI_NORMAL; + } + + void printElided(unsigned int value, const std::string_view single, const std::string_view plural) + { + ::nix::printElided(output, value, single, plural, options.ansiColors); + } + + void printInt(Value & v) + { + if (options.ansiColors) + output << ANSI_CYAN; + output << v.integer; + if (options.ansiColors) + output << ANSI_NORMAL; + } + + void printFloat(Value & v) + { + if (options.ansiColors) + output << ANSI_CYAN; + output << v.fpoint; + if (options.ansiColors) + output << ANSI_NORMAL; + } + + void printBool(Value & v) + { + if (options.ansiColors) + output << ANSI_CYAN; + printLiteralBool(output, v.boolean); + if (options.ansiColors) + output << ANSI_NORMAL; + } + + void printString(Value & v) + { + printLiteralString(output, v.string_view(), options.maxStringLength, options.ansiColors); + } + + void printPath(Value & v) + { + if (options.ansiColors) + output << ANSI_GREEN; + output << v.path().to_string(); // !!! escaping? + if (options.ansiColors) + output << ANSI_NORMAL; + } + + void printNull() + { + if (options.ansiColors) + output << ANSI_CYAN; + output << "null"; + if (options.ansiColors) + output << ANSI_NORMAL; + } + + void printDerivation(Value & v) + { + try { + Bindings::iterator i = v.attrs->find(state.sDrvPath); + NixStringContext context; + std::string storePath; + if (i != v.attrs->end()) + storePath = state.store->printStorePath(state.coerceToStorePath(i->pos, *i->value, context, "while evaluating the drvPath of a derivation")); + + if (options.ansiColors) + output << ANSI_GREEN; + output << "«derivation"; + if (!storePath.empty()) { + output << " " << storePath; + } + output << "»"; + if (options.ansiColors) + output << ANSI_NORMAL; + } catch (BaseError & e) { + printError_(e); + } + } + + void printAttrs(Value & v, size_t depth) + { + if (seen && !seen->insert(&v).second) { + printRepeated(); + return; + } + + if (options.force && options.derivationPaths && state.isDerivation(v)) { + printDerivation(v); + } else if (depth < options.maxDepth) { + output << "{ "; + + std::vector> sorted; + for (auto & i : *v.attrs) + sorted.emplace_back(std::pair(state.symbols[i.name], i.value)); + + if (options.maxAttrs == std::numeric_limits::max()) + std::sort(sorted.begin(), sorted.end()); + else + std::sort(sorted.begin(), sorted.end(), ImportantFirstAttrNameCmp()); + + size_t attrsPrinted = 0; + for (auto & i : sorted) { + if (attrsPrinted >= options.maxAttrs) { + printElided(sorted.size() - attrsPrinted, "attribute", "attributes"); + break; + } + + printAttributeName(output, i.first); + output << " = "; + print(*i.second, depth + 1); + output << "; "; + attrsPrinted++; + } + + output << "}"; + } else + output << "{ ... }"; + } + + void printList(Value & v, size_t depth) + { + if (seen && v.listSize() && !seen->insert(&v).second) { + printRepeated(); + return; + } + + output << "[ "; + if (depth < options.maxDepth) { + size_t listItemsPrinted = 0; + for (auto elem : v.listItems()) { + if (listItemsPrinted >= options.maxListItems) { + printElided(v.listSize() - listItemsPrinted, "item", "items"); + break; + } + + if (elem) { + print(*elem, depth + 1); + } else { + printNullptr(); + } + output << " "; + listItemsPrinted++; + } + } + else + output << "... "; + output << "]"; + } + + void printFunction(Value & v) + { + if (options.ansiColors) + output << ANSI_BLUE; + output << "«"; + + if (v.isLambda()) { + output << "lambda"; + if (v.lambda.fun) { + if (v.lambda.fun->name) { + output << " " << state.symbols[v.lambda.fun->name]; + } + + std::ostringstream s; + s << state.positions[v.lambda.fun->pos]; + output << " @ " << filterANSIEscapes(s.str()); + } + } else if (v.isPrimOp()) { + if (v.primOp) + output << *v.primOp; + else + output << "primop"; + } else if (v.isPrimOpApp()) { + output << "partially applied "; + auto primOp = v.primOpAppPrimOp(); + if (primOp) + output << *primOp; + else + output << "primop"; + } else { + abort(); + } + + output << "»"; + if (options.ansiColors) + output << ANSI_NORMAL; + } + + void printThunk(Value & v) + { + if (v.isBlackhole()) { + // Although we know for sure that it's going to be an infinite recursion + // when this value is accessed _in the current context_, it's likely + // that the user will misinterpret a simpler «infinite recursion» output + // as a definitive statement about the value, while in fact it may be + // a valid value after `builtins.trace` and perhaps some other steps + // have completed. + if (options.ansiColors) + output << ANSI_RED; + output << "«potential infinite recursion»"; + if (options.ansiColors) + output << ANSI_NORMAL; + } else if (v.isThunk() || v.isApp()) { + if (options.ansiColors) + output << ANSI_MAGENTA; + output << "«thunk»"; + if (options.ansiColors) + output << ANSI_NORMAL; + } else { + abort(); + } + } + + void printExternal(Value & v) + { + v.external->print(output); + } + + void printUnknown() + { + if (options.ansiColors) + output << ANSI_RED; + output << "«unknown»"; + if (options.ansiColors) + output << ANSI_NORMAL; + } + + void printError_(BaseError & e) + { + if (options.ansiColors) + output << ANSI_RED; + output << "«" << e.msg() << "»"; + if (options.ansiColors) + output << ANSI_NORMAL; + } + + void print(Value & v, size_t depth) + { + output.flush(); + checkInterrupt(); + + if (options.force) { + try { + state.forceValue(v, v.determinePos(noPos)); + } catch (BaseError & e) { + printError_(e); + return; + } + } + + switch (v.type()) { + + case nInt: + printInt(v); + break; + + case nFloat: + printFloat(v); + break; + + case nBool: + printBool(v); + break; + + case nString: + printString(v); + break; + + case nPath: + printPath(v); + break; + + case nNull: + printNull(); + break; + + case nAttrs: + printAttrs(v, depth); + break; + + case nList: + printList(v, depth); + break; + + case nFunction: + printFunction(v); + break; + + case nThunk: + printThunk(v); + break; + + case nExternal: + printExternal(v); + break; + + default: + printUnknown(); + break; + } + } + +public: + Printer(std::ostream & output, EvalState & state, PrintOptions options) + : output(output), state(state), options(options) { } + + void print(Value & v) + { + if (options.trackRepeated) { + seen.emplace(); + } else { + seen.reset(); + } + + ValuesSeen seen; + print(v, 0); + } +}; + +void printValue(EvalState & state, std::ostream & output, Value & v, PrintOptions options) +{ + Printer(output, state, options).print(v); +} } diff --git a/src/libexpr/print.hh b/src/libexpr/print.hh index abf830864..40207d777 100644 --- a/src/libexpr/print.hh +++ b/src/libexpr/print.hh @@ -9,6 +9,9 @@ #include +#include "eval.hh" +#include "print-options.hh" + namespace nix { /** @@ -16,6 +19,7 @@ namespace nix { * * Quotes and fairly minimal escaping are added. * + * @param o The output stream to print to * @param s The logical string */ std::ostream & printLiteralString(std::ostream & o, std::string_view s); @@ -53,4 +57,6 @@ bool isReservedKeyword(const std::string_view str); */ std::ostream & printIdentifier(std::ostream & o, std::string_view s); +void printValue(EvalState & state, std::ostream & str, Value & v, PrintOptions options = PrintOptions {}); + } diff --git a/src/libexpr/value.hh b/src/libexpr/value.hh index c65b336b0..214d52271 100644 --- a/src/libexpr/value.hh +++ b/src/libexpr/value.hh @@ -9,6 +9,7 @@ #include "value/context.hh" #include "input-accessor.hh" #include "source-path.hh" +#include "print-options.hh" #if HAVE_BOEHMGC #include @@ -70,7 +71,7 @@ struct Pos; class StorePath; class EvalState; class XMLWriter; - +class Printer; typedef int64_t NixInt; typedef double NixFloat; @@ -82,6 +83,7 @@ typedef double NixFloat; class ExternalValueBase { friend std::ostream & operator << (std::ostream & str, const ExternalValueBase & v); + friend class Printer; protected: /** * Print out the value @@ -139,11 +141,9 @@ private: friend std::string showType(const Value & v); - void print(const SymbolTable &symbols, std::ostream &str, std::set *seen, int depth) const; - public: - void print(const SymbolTable &symbols, std::ostream &str, bool showRepeated = false, int depth = INT_MAX) const; + void print(EvalState &state, std::ostream &str, PrintOptions options = PrintOptions {}); // Functions needed to distinguish the type // These should be removed eventually, by putting the functionality that's @@ -364,10 +364,15 @@ public: inline void mkPrimOpApp(Value * l, Value * r) { internalType = tPrimOpApp; - app.left = l; - app.right = r; + primOpApp.left = l; + primOpApp.right = r; } + /** + * For a `tPrimOpApp` value, get the original `PrimOp` value. + */ + PrimOp * primOpAppPrimOp() const; + inline void mkExternal(ExternalValueBase * e) { clearValue(); diff --git a/src/libutil/english.cc b/src/libutil/english.cc new file mode 100644 index 000000000..8c93c9156 --- /dev/null +++ b/src/libutil/english.cc @@ -0,0 +1,18 @@ +#include "english.hh" + +namespace nix { + +std::ostream & pluralize( + std::ostream & output, + unsigned int count, + const std::string_view single, + const std::string_view plural) +{ + if (count == 1) + output << "1 " << single; + else + output << count << " " << plural; + return output; +} + +} diff --git a/src/libutil/english.hh b/src/libutil/english.hh new file mode 100644 index 000000000..9c6c93571 --- /dev/null +++ b/src/libutil/english.hh @@ -0,0 +1,18 @@ +#pragma once + +#include + +namespace nix { + +/** + * Pluralize a given value. + * + * If `count == 1`, prints `1 {single}` to `output`, otherwise prints `{count} {plural}`. + */ +std::ostream & pluralize( + std::ostream & output, + unsigned int count, + const std::string_view single, + const std::string_view plural); + +} diff --git a/src/nix-env/user-env.cc b/src/nix-env/user-env.cc index 9f4d063d2..3d07cab7a 100644 --- a/src/nix-env/user-env.cc +++ b/src/nix-env/user-env.cc @@ -8,6 +8,8 @@ #include "eval.hh" #include "eval-inline.hh" #include "profiles.hh" +#include "print-ambiguous.hh" +#include namespace nix { @@ -106,7 +108,8 @@ bool createUserEnv(EvalState & state, DrvInfos & elems, environment. */ auto manifestFile = ({ std::ostringstream str; - manifest.print(state.symbols, str, true); + std::set seen; + printAmbiguous(manifest, state.symbols, str, &seen, std::numeric_limits::max()); // TODO with C++20 we can use str.view() instead and avoid copy. std::string str2 = str.str(); StringSource source { str2 }; diff --git a/src/nix-instantiate/nix-instantiate.cc b/src/nix-instantiate/nix-instantiate.cc index ab590b3a6..9b36dccc6 100644 --- a/src/nix-instantiate/nix-instantiate.cc +++ b/src/nix-instantiate/nix-instantiate.cc @@ -56,7 +56,7 @@ void processExpr(EvalState & state, const Strings & attrPaths, std::cout << std::endl; } else { if (strict) state.forceValueDeep(vRes); - vRes.print(state.symbols, std::cout); + vRes.print(state, std::cout); std::cout << std::endl; } } else { diff --git a/tests/functional/lang/eval-okay-print.err.exp b/tests/functional/lang/eval-okay-print.err.exp index 3fc99be3e..80aa17c6e 100644 --- a/tests/functional/lang/eval-okay-print.err.exp +++ b/tests/functional/lang/eval-okay-print.err.exp @@ -1 +1 @@ -trace: [ ] +trace: [ «thunk» ] diff --git a/tests/functional/lang/eval-okay-print.exp b/tests/functional/lang/eval-okay-print.exp index 0d960fb70..aa1b2379e 100644 --- a/tests/functional/lang/eval-okay-print.exp +++ b/tests/functional/lang/eval-okay-print.exp @@ -1 +1 @@ -[ null [ [ «repeated» ] ] ] +[ null «primop toString» «partially applied primop deepSeq» «lambda @ /pwd/lang/eval-okay-print.nix:1:61» [ [ «repeated» ] ] ] diff --git a/tests/functional/lang/eval-okay-repeated-empty-attrs.exp b/tests/functional/lang/eval-okay-repeated-empty-attrs.exp new file mode 100644 index 000000000..d21e6db6b --- /dev/null +++ b/tests/functional/lang/eval-okay-repeated-empty-attrs.exp @@ -0,0 +1 @@ +[ { } { } ] diff --git a/tests/functional/lang/eval-okay-repeated-empty-attrs.nix b/tests/functional/lang/eval-okay-repeated-empty-attrs.nix new file mode 100644 index 000000000..030a3b85c --- /dev/null +++ b/tests/functional/lang/eval-okay-repeated-empty-attrs.nix @@ -0,0 +1,2 @@ +# Tests that empty attribute sets are not printed as `«repeated»`. +[ {} {} ] diff --git a/tests/functional/lang/eval-okay-repeated-empty-list.exp b/tests/functional/lang/eval-okay-repeated-empty-list.exp new file mode 100644 index 000000000..701fc7e20 --- /dev/null +++ b/tests/functional/lang/eval-okay-repeated-empty-list.exp @@ -0,0 +1 @@ +[ [ ] [ ] ] diff --git a/tests/functional/lang/eval-okay-repeated-empty-list.nix b/tests/functional/lang/eval-okay-repeated-empty-list.nix new file mode 100644 index 000000000..376c51be8 --- /dev/null +++ b/tests/functional/lang/eval-okay-repeated-empty-list.nix @@ -0,0 +1 @@ +[ [] [] ] diff --git a/tests/unit/libexpr/value/print.cc b/tests/unit/libexpr/value/print.cc index a4f6fc014..98131112e 100644 --- a/tests/unit/libexpr/value/print.cc +++ b/tests/unit/libexpr/value/print.cc @@ -1,6 +1,7 @@ #include "tests/libexpr.hh" #include "value.hh" +#include "print.hh" namespace nix { @@ -12,7 +13,7 @@ struct ValuePrintingTests : LibExprTest void test(Value v, std::string_view expected, A... args) { std::stringstream out; - v.print(state.symbols, out, args...); + v.print(state, out, args...); ASSERT_EQ(out.str(), expected); } }; @@ -84,7 +85,7 @@ TEST_F(ValuePrintingTests, tList) vList.bigList.elems[1] = &vTwo; vList.bigList.size = 3; - test(vList, "[ 1 2 (nullptr) ]"); + test(vList, "[ 1 2 «nullptr» ]"); } TEST_F(ValuePrintingTests, vThunk) @@ -92,7 +93,7 @@ TEST_F(ValuePrintingTests, vThunk) Value vThunk; vThunk.mkThunk(nullptr, nullptr); - test(vThunk, ""); + test(vThunk, "«thunk»"); } TEST_F(ValuePrintingTests, vApp) @@ -100,32 +101,55 @@ TEST_F(ValuePrintingTests, vApp) Value vApp; vApp.mkApp(nullptr, nullptr); - test(vApp, ""); + test(vApp, "«thunk»"); } TEST_F(ValuePrintingTests, vLambda) { - Value vLambda; - vLambda.mkLambda(nullptr, nullptr); + Env env { + .up = nullptr, + .values = { } + }; + PosTable::Origin origin((std::monostate())); + auto posIdx = state.positions.add(origin, 1, 1); + auto body = ExprInt(0); + auto formals = Formals {}; - test(vLambda, ""); + ExprLambda eLambda(posIdx, createSymbol("a"), &formals, &body); + + Value vLambda; + vLambda.mkLambda(&env, &eLambda); + + test(vLambda, "«lambda @ «none»:1:1»"); + + eLambda.setName(createSymbol("puppy")); + + test(vLambda, "«lambda puppy @ «none»:1:1»"); } TEST_F(ValuePrintingTests, vPrimOp) { Value vPrimOp; - PrimOp primOp{}; + PrimOp primOp{ + .name = "puppy" + }; vPrimOp.mkPrimOp(&primOp); - test(vPrimOp, ""); + test(vPrimOp, "«primop puppy»"); } TEST_F(ValuePrintingTests, vPrimOpApp) { - Value vPrimOpApp; - vPrimOpApp.mkPrimOpApp(nullptr, nullptr); + PrimOp primOp{ + .name = "puppy" + }; + Value vPrimOp; + vPrimOp.mkPrimOp(&primOp); - test(vPrimOpApp, ""); + Value vPrimOpApp; + vPrimOpApp.mkPrimOpApp(&vPrimOp, nullptr); + + test(vPrimOpApp, "«partially applied primop puppy»"); } TEST_F(ValuePrintingTests, vExternal) @@ -176,9 +200,14 @@ TEST_F(ValuePrintingTests, depthAttrs) Value vTwo; vTwo.mkInt(2); + BindingsBuilder builderEmpty(state, state.allocBindings(0)); + Value vAttrsEmpty; + vAttrsEmpty.mkAttrs(builderEmpty.finish()); + BindingsBuilder builder(state, state.allocBindings(10)); builder.insert(state.symbols.create("one"), &vOne); builder.insert(state.symbols.create("two"), &vTwo); + builder.insert(state.symbols.create("nested"), &vAttrsEmpty); Value vAttrs; vAttrs.mkAttrs(builder.finish()); @@ -191,10 +220,10 @@ TEST_F(ValuePrintingTests, depthAttrs) Value vNested; vNested.mkAttrs(builder2.finish()); - test(vNested, "{ nested = «too deep»; one = «too deep»; two = «too deep»; }", false, 1); - test(vNested, "{ nested = { one = «too deep»; two = «too deep»; }; one = 1; two = 2; }", false, 2); - test(vNested, "{ nested = { one = 1; two = 2; }; one = 1; two = 2; }", false, 3); - test(vNested, "{ nested = { one = 1; two = 2; }; one = 1; two = 2; }", false, 4); + test(vNested, "{ nested = { ... }; one = 1; two = 2; }", PrintOptions { .maxDepth = 1 }); + test(vNested, "{ nested = { nested = { ... }; one = 1; two = 2; }; one = 1; two = 2; }", PrintOptions { .maxDepth = 2 }); + test(vNested, "{ nested = { nested = { }; one = 1; two = 2; }; one = 1; two = 2; }", PrintOptions { .maxDepth = 3 }); + test(vNested, "{ nested = { nested = { }; one = 1; two = 2; }; one = 1; two = 2; }", PrintOptions { .maxDepth = 4 }); } TEST_F(ValuePrintingTests, depthList) @@ -227,11 +256,561 @@ TEST_F(ValuePrintingTests, depthList) vList.bigList.elems[2] = &vNested; vList.bigList.size = 3; - test(vList, "[ «too deep» «too deep» «too deep» ]", false, 1); - test(vList, "[ 1 2 { nested = «too deep»; one = «too deep»; two = «too deep»; } ]", false, 2); - test(vList, "[ 1 2 { nested = { one = «too deep»; two = «too deep»; }; one = 1; two = 2; } ]", false, 3); - test(vList, "[ 1 2 { nested = { one = 1; two = 2; }; one = 1; two = 2; } ]", false, 4); - test(vList, "[ 1 2 { nested = { one = 1; two = 2; }; one = 1; two = 2; } ]", false, 5); + test(vList, "[ 1 2 { ... } ]", PrintOptions { .maxDepth = 1 }); + test(vList, "[ 1 2 { nested = { ... }; one = 1; two = 2; } ]", PrintOptions { .maxDepth = 2 }); + test(vList, "[ 1 2 { nested = { one = 1; two = 2; }; one = 1; two = 2; } ]", PrintOptions { .maxDepth = 3 }); + test(vList, "[ 1 2 { nested = { one = 1; two = 2; }; one = 1; two = 2; } ]", PrintOptions { .maxDepth = 4 }); + test(vList, "[ 1 2 { nested = { one = 1; two = 2; }; one = 1; two = 2; } ]", PrintOptions { .maxDepth = 5 }); +} + +struct StringPrintingTests : LibExprTest +{ + template + void test(std::string_view literal, std::string_view expected, unsigned int maxLength, A... args) + { + Value v; + v.mkString(literal); + + std::stringstream out; + printValue(state, out, v, PrintOptions { + .maxStringLength = maxLength + }); + ASSERT_EQ(out.str(), expected); + } +}; + +TEST_F(StringPrintingTests, maxLengthTruncation) +{ + test("abcdefghi", "\"abcdefghi\"", 10); + test("abcdefghij", "\"abcdefghij\"", 10); + test("abcdefghijk", "\"abcdefghij\" «1 byte elided»", 10); + test("abcdefghijkl", "\"abcdefghij\" «2 bytes elided»", 10); + test("abcdefghijklm", "\"abcdefghij\" «3 bytes elided»", 10); +} + +// Check that printing an attrset shows 'important' attributes like `type` +// first, but only reorder the attrs when we have a maxAttrs budget. +TEST_F(ValuePrintingTests, attrsTypeFirst) +{ + Value vType; + vType.mkString("puppy"); + + Value vApple; + vApple.mkString("apple"); + + BindingsBuilder builder(state, state.allocBindings(10)); + builder.insert(state.symbols.create("type"), &vType); + builder.insert(state.symbols.create("apple"), &vApple); + + Value vAttrs; + vAttrs.mkAttrs(builder.finish()); + + test(vAttrs, + "{ type = \"puppy\"; apple = \"apple\"; }", + PrintOptions { + .maxAttrs = 100 + }); + + test(vAttrs, + "{ apple = \"apple\"; type = \"puppy\"; }", + PrintOptions { }); +} + +TEST_F(ValuePrintingTests, ansiColorsInt) +{ + Value v; + v.mkInt(10); + + test(v, + ANSI_CYAN "10" ANSI_NORMAL, + PrintOptions { + .ansiColors = true + }); +} + +TEST_F(ValuePrintingTests, ansiColorsFloat) +{ + Value v; + v.mkFloat(1.6); + + test(v, + ANSI_CYAN "1.6" ANSI_NORMAL, + PrintOptions { + .ansiColors = true + }); +} + +TEST_F(ValuePrintingTests, ansiColorsBool) +{ + Value v; + v.mkBool(true); + + test(v, + ANSI_CYAN "true" ANSI_NORMAL, + PrintOptions { + .ansiColors = true + }); +} + +TEST_F(ValuePrintingTests, ansiColorsString) +{ + Value v; + v.mkString("puppy"); + + test(v, + ANSI_MAGENTA "\"puppy\"" ANSI_NORMAL, + PrintOptions { + .ansiColors = true + }); +} + +TEST_F(ValuePrintingTests, ansiColorsStringElided) +{ + Value v; + v.mkString("puppy"); + + test(v, + ANSI_MAGENTA "\"pup\"" ANSI_FAINT " «2 bytes elided»" ANSI_NORMAL, + PrintOptions { + .ansiColors = true, + .maxStringLength = 3 + }); +} + +TEST_F(ValuePrintingTests, ansiColorsPath) +{ + Value v; + v.mkPath(state.rootPath(CanonPath("puppy"))); + + test(v, + ANSI_GREEN "/puppy" ANSI_NORMAL, + PrintOptions { + .ansiColors = true + }); +} + +TEST_F(ValuePrintingTests, ansiColorsNull) +{ + Value v; + v.mkNull(); + + test(v, + ANSI_CYAN "null" ANSI_NORMAL, + PrintOptions { + .ansiColors = true + }); +} + +TEST_F(ValuePrintingTests, ansiColorsAttrs) +{ + Value vOne; + vOne.mkInt(1); + + Value vTwo; + vTwo.mkInt(2); + + BindingsBuilder builder(state, state.allocBindings(10)); + builder.insert(state.symbols.create("one"), &vOne); + builder.insert(state.symbols.create("two"), &vTwo); + + Value vAttrs; + vAttrs.mkAttrs(builder.finish()); + + test(vAttrs, + "{ one = " ANSI_CYAN "1" ANSI_NORMAL "; two = " ANSI_CYAN "2" ANSI_NORMAL "; }", + PrintOptions { + .ansiColors = true + }); +} + +TEST_F(ValuePrintingTests, ansiColorsDerivation) +{ + Value vDerivation; + vDerivation.mkString("derivation"); + + BindingsBuilder builder(state, state.allocBindings(10)); + builder.insert(state.sType, &vDerivation); + + Value vAttrs; + vAttrs.mkAttrs(builder.finish()); + + test(vAttrs, + ANSI_GREEN "«derivation»" ANSI_NORMAL, + PrintOptions { + .ansiColors = true, + .force = true, + .derivationPaths = true + }); + + test(vAttrs, + "{ type = " ANSI_MAGENTA "\"derivation\"" ANSI_NORMAL "; }", + PrintOptions { + .ansiColors = true, + .force = true + }); +} + +TEST_F(ValuePrintingTests, ansiColorsError) +{ + Value throw_ = state.getBuiltin("throw"); + Value message; + message.mkString("uh oh!"); + Value vError; + vError.mkApp(&throw_, &message); + + test(vError, + ANSI_RED + "«" + ANSI_RED + "error:" + ANSI_NORMAL + "\n … while calling the '" + ANSI_MAGENTA + "throw" + ANSI_NORMAL + "' builtin\n\n " + ANSI_RED + "error:" + ANSI_NORMAL + " uh oh!»" + ANSI_NORMAL, + PrintOptions { + .ansiColors = true, + .force = true, + }); +} + +TEST_F(ValuePrintingTests, ansiColorsDerivationError) +{ + Value throw_ = state.getBuiltin("throw"); + Value message; + message.mkString("uh oh!"); + Value vError; + vError.mkApp(&throw_, &message); + + Value vDerivation; + vDerivation.mkString("derivation"); + + BindingsBuilder builder(state, state.allocBindings(10)); + builder.insert(state.sType, &vDerivation); + builder.insert(state.sDrvPath, &vError); + + Value vAttrs; + vAttrs.mkAttrs(builder.finish()); + + test(vAttrs, + "{ drvPath = " + ANSI_RED + "«" + ANSI_RED + "error:" + ANSI_NORMAL + "\n … while calling the '" + ANSI_MAGENTA + "throw" + ANSI_NORMAL + "' builtin\n\n " + ANSI_RED + "error:" + ANSI_NORMAL + " uh oh!»" + ANSI_NORMAL + "; type = " + ANSI_MAGENTA + "\"derivation\"" + ANSI_NORMAL + "; }", + PrintOptions { + .ansiColors = true, + .force = true + }); + + test(vAttrs, + ANSI_RED + "«" + ANSI_RED + "error:" + ANSI_NORMAL + "\n … while calling the '" + ANSI_MAGENTA + "throw" + ANSI_NORMAL + "' builtin\n\n " + ANSI_RED + "error:" + ANSI_NORMAL + " uh oh!»" + ANSI_NORMAL, + PrintOptions { + .ansiColors = true, + .force = true, + .derivationPaths = true, + }); +} + +TEST_F(ValuePrintingTests, ansiColorsAssert) +{ + ExprVar eFalse(state.symbols.create("false")); + eFalse.bindVars(state, state.staticBaseEnv); + ExprInt eInt(1); + + ExprAssert expr(noPos, &eFalse, &eInt); + + Value v; + state.mkThunk_(v, &expr); + + test(v, + ANSI_RED "«" ANSI_RED "error:" ANSI_NORMAL " assertion '" ANSI_MAGENTA "false" ANSI_NORMAL "' failed»" ANSI_NORMAL, + PrintOptions { + .ansiColors = true, + .force = true + }); +} + +TEST_F(ValuePrintingTests, ansiColorsList) +{ + Value vOne; + vOne.mkInt(1); + + Value vTwo; + vTwo.mkInt(2); + + Value vList; + state.mkList(vList, 5); + vList.bigList.elems[0] = &vOne; + vList.bigList.elems[1] = &vTwo; + vList.bigList.size = 3; + + test(vList, + "[ " ANSI_CYAN "1" ANSI_NORMAL " " ANSI_CYAN "2" ANSI_NORMAL " " ANSI_MAGENTA "«nullptr»" ANSI_NORMAL " ]", + PrintOptions { + .ansiColors = true + }); +} + +TEST_F(ValuePrintingTests, ansiColorsLambda) +{ + Env env { + .up = nullptr, + .values = { } + }; + PosTable::Origin origin((std::monostate())); + auto posIdx = state.positions.add(origin, 1, 1); + auto body = ExprInt(0); + auto formals = Formals {}; + + ExprLambda eLambda(posIdx, createSymbol("a"), &formals, &body); + + Value vLambda; + vLambda.mkLambda(&env, &eLambda); + + test(vLambda, + ANSI_BLUE "«lambda @ «none»:1:1»" ANSI_NORMAL, + PrintOptions { + .ansiColors = true, + .force = true + }); + + eLambda.setName(createSymbol("puppy")); + + test(vLambda, + ANSI_BLUE "«lambda puppy @ «none»:1:1»" ANSI_NORMAL, + PrintOptions { + .ansiColors = true, + .force = true + }); +} + +TEST_F(ValuePrintingTests, ansiColorsPrimOp) +{ + PrimOp primOp{ + .name = "puppy" + }; + Value v; + v.mkPrimOp(&primOp); + + test(v, + ANSI_BLUE "«primop puppy»" ANSI_NORMAL, + PrintOptions { + .ansiColors = true + }); +} + +TEST_F(ValuePrintingTests, ansiColorsPrimOpApp) +{ + PrimOp primOp{ + .name = "puppy" + }; + Value vPrimOp; + vPrimOp.mkPrimOp(&primOp); + + Value v; + v.mkPrimOpApp(&vPrimOp, nullptr); + + test(v, + ANSI_BLUE "«partially applied primop puppy»" ANSI_NORMAL, + PrintOptions { + .ansiColors = true + }); +} + +TEST_F(ValuePrintingTests, ansiColorsThunk) +{ + Value v; + v.mkThunk(nullptr, nullptr); + + test(v, + ANSI_MAGENTA "«thunk»" ANSI_NORMAL, + PrintOptions { + .ansiColors = true + }); +} + +TEST_F(ValuePrintingTests, ansiColorsBlackhole) +{ + Value v; + v.mkBlackhole(); + + test(v, + ANSI_RED "«potential infinite recursion»" ANSI_NORMAL, + PrintOptions { + .ansiColors = true + }); +} + +TEST_F(ValuePrintingTests, ansiColorsAttrsRepeated) +{ + BindingsBuilder emptyBuilder(state, state.allocBindings(1)); + + Value vEmpty; + vEmpty.mkAttrs(emptyBuilder.finish()); + + BindingsBuilder builder(state, state.allocBindings(10)); + builder.insert(state.symbols.create("a"), &vEmpty); + builder.insert(state.symbols.create("b"), &vEmpty); + + Value vAttrs; + vAttrs.mkAttrs(builder.finish()); + + test(vAttrs, + "{ a = { }; b = " ANSI_MAGENTA "«repeated»" ANSI_NORMAL "; }", + PrintOptions { + .ansiColors = true + }); +} + +TEST_F(ValuePrintingTests, ansiColorsListRepeated) +{ + BindingsBuilder emptyBuilder(state, state.allocBindings(1)); + + Value vEmpty; + vEmpty.mkAttrs(emptyBuilder.finish()); + + Value vList; + state.mkList(vList, 3); + vList.bigList.elems[0] = &vEmpty; + vList.bigList.elems[1] = &vEmpty; + vList.bigList.size = 2; + + test(vList, + "[ { } " ANSI_MAGENTA "«repeated»" ANSI_NORMAL " ]", + PrintOptions { + .ansiColors = true + }); +} + +TEST_F(ValuePrintingTests, listRepeated) +{ + BindingsBuilder emptyBuilder(state, state.allocBindings(1)); + + Value vEmpty; + vEmpty.mkAttrs(emptyBuilder.finish()); + + Value vList; + state.mkList(vList, 3); + vList.bigList.elems[0] = &vEmpty; + vList.bigList.elems[1] = &vEmpty; + vList.bigList.size = 2; + + test(vList, "[ { } «repeated» ]", PrintOptions { }); + test(vList, + "[ { } { } ]", + PrintOptions { + .trackRepeated = false + }); +} + +TEST_F(ValuePrintingTests, ansiColorsAttrsElided) +{ + Value vOne; + vOne.mkInt(1); + + Value vTwo; + vTwo.mkInt(2); + + BindingsBuilder builder(state, state.allocBindings(10)); + builder.insert(state.symbols.create("one"), &vOne); + builder.insert(state.symbols.create("two"), &vTwo); + + Value vAttrs; + vAttrs.mkAttrs(builder.finish()); + + test(vAttrs, + "{ one = " ANSI_CYAN "1" ANSI_NORMAL "; " ANSI_FAINT " «1 attribute elided»" ANSI_NORMAL "}", + PrintOptions { + .ansiColors = true, + .maxAttrs = 1 + }); + + Value vThree; + vThree.mkInt(3); + + builder.insert(state.symbols.create("three"), &vThree); + vAttrs.mkAttrs(builder.finish()); + + test(vAttrs, + "{ one = " ANSI_CYAN "1" ANSI_NORMAL "; " ANSI_FAINT " «2 attributes elided»" ANSI_NORMAL "}", + PrintOptions { + .ansiColors = true, + .maxAttrs = 1 + }); +} + +TEST_F(ValuePrintingTests, ansiColorsListElided) +{ + BindingsBuilder emptyBuilder(state, state.allocBindings(1)); + + Value vOne; + vOne.mkInt(1); + + Value vTwo; + vTwo.mkInt(2); + + Value vList; + state.mkList(vList, 4); + vList.bigList.elems[0] = &vOne; + vList.bigList.elems[1] = &vTwo; + vList.bigList.size = 2; + + test(vList, + "[ " ANSI_CYAN "1" ANSI_NORMAL " " ANSI_FAINT " «1 item elided»" ANSI_NORMAL "]", + PrintOptions { + .ansiColors = true, + .maxListItems = 1 + }); + + Value vThree; + vThree.mkInt(3); + + vList.bigList.elems[2] = &vThree; + vList.bigList.size = 3; + + test(vList, + "[ " ANSI_CYAN "1" ANSI_NORMAL " " ANSI_FAINT " «2 items elided»" ANSI_NORMAL "]", + PrintOptions { + .ansiColors = true, + .maxListItems = 1 + }); } } // namespace nix From df84dd4d8dd3fd6381ac2ca3064432ab31a16b79 Mon Sep 17 00:00:00 2001 From: Rebecca Turner Date: Tue, 9 Jan 2024 11:13:45 -0800 Subject: [PATCH 3/3] Restore ambiguous value printer for `nix-instantiate` The Nix team has requested that this output format remain unchanged. I've added a warning to the man page explaining that `nix-instantiate --eval` output will not parse correctly in many situations. --- doc/manual/src/command-ref/nix-instantiate.md | 80 ++++++++++---- src/libexpr/print-ambiguous.cc | 100 ++++++++++++++++++ src/libexpr/print-ambiguous.hh | 24 +++++ src/nix-env/user-env.cc | 3 +- src/nix-instantiate/nix-instantiate.cc | 6 +- tests/functional/lang/eval-okay-print.exp | 2 +- 6 files changed, 189 insertions(+), 26 deletions(-) create mode 100644 src/libexpr/print-ambiguous.cc create mode 100644 src/libexpr/print-ambiguous.hh diff --git a/doc/manual/src/command-ref/nix-instantiate.md b/doc/manual/src/command-ref/nix-instantiate.md index e1b4a3e80..483150aa8 100644 --- a/doc/manual/src/command-ref/nix-instantiate.md +++ b/doc/manual/src/command-ref/nix-instantiate.md @@ -35,13 +35,50 @@ standard input. - `--parse`\ Just parse the input files, and print their abstract syntax trees on - standard output in ATerm format. + standard output as a Nix expression. - `--eval`\ Just parse and evaluate the input files, and print the resulting values on standard output. No instantiation of store derivations takes place. + > **Warning** + > + > This option produces ambiguous output which is not suitable for machine + > consumption. For example, these two Nix expressions print the same result + > despite having different types: + > + > ```console + > $ nix-instantiate --eval --expr '{ a = {}; }' + > { a = ; } + > $ nix-instantiate --eval --expr '{ a = ; }' + > { a = ; } + > ``` + > + > For human-readable output, `nix eval` (experimental) is more informative: + > + > ```console + > $ nix-instantiate --eval --expr 'a: a' + > + > $ nix eval --expr 'a: a' + > «lambda @ «string»:1:1» + > ``` + > + > For machine-readable output, the `--xml` option produces unambiguous + > output: + > + > ```console + > $ nix-instantiate --eval --xml --expr '{ foo = ; }' + > + > + > + > + > + > + > + > + > ``` + - `--find-file`\ Look up the given files in Nix’s search path (as specified by the `NIX_PATH` environment variable). If found, print the corresponding @@ -61,11 +98,11 @@ standard input. - `--json`\ When used with `--eval`, print the resulting value as an JSON - representation of the abstract syntax tree rather than as an ATerm. + representation of the abstract syntax tree rather than as a Nix expression. - `--xml`\ When used with `--eval`, print the resulting value as an XML - representation of the abstract syntax tree rather than as an ATerm. + representation of the abstract syntax tree rather than as a Nix expression. The schema is the same as that used by the [`toXML` built-in](../language/builtins.md). @@ -133,28 +170,29 @@ $ nix-instantiate --eval --xml --expr '1 + 2' The difference between non-strict and strict evaluation: ```console -$ nix-instantiate --eval --xml --expr 'rec { x = "foo"; y = x; }' -... - - - - - - -... +$ nix-instantiate --eval --xml --expr '{ x = {}; }' + + + + + + + + ``` Note that `y` is left unevaluated (the XML representation doesn’t attempt to show non-normal forms). ```console -$ nix-instantiate --eval --xml --strict --expr 'rec { x = "foo"; y = x; }' -... - - - - - - -... +$ nix-instantiate --eval --xml --strict --expr '{ x = {}; }' + + + + + + + + + ``` diff --git a/src/libexpr/print-ambiguous.cc b/src/libexpr/print-ambiguous.cc new file mode 100644 index 000000000..07c398dd2 --- /dev/null +++ b/src/libexpr/print-ambiguous.cc @@ -0,0 +1,100 @@ +#include "print-ambiguous.hh" +#include "print.hh" +#include "signals.hh" + +namespace nix { + +// See: https://github.com/NixOS/nix/issues/9730 +void printAmbiguous( + Value &v, + const SymbolTable &symbols, + std::ostream &str, + std::set *seen, + int depth) +{ + checkInterrupt(); + + if (depth <= 0) { + str << "«too deep»"; + return; + } + switch (v.type()) { + case nInt: + str << v.integer; + break; + case nBool: + printLiteralBool(str, v.boolean); + break; + case nString: + printLiteralString(str, v.string_view()); + break; + case nPath: + str << v.path().to_string(); // !!! escaping? + break; + case nNull: + str << "null"; + break; + case nAttrs: { + if (seen && !v.attrs->empty() && !seen->insert(v.attrs).second) + str << "«repeated»"; + else { + str << "{ "; + for (auto & i : v.attrs->lexicographicOrder(symbols)) { + str << symbols[i->name] << " = "; + printAmbiguous(*i->value, symbols, str, seen, depth - 1); + str << "; "; + } + str << "}"; + } + break; + } + case nList: + if (seen && v.listSize() && !seen->insert(v.listElems()).second) + str << "«repeated»"; + else { + str << "[ "; + for (auto v2 : v.listItems()) { + if (v2) + printAmbiguous(*v2, symbols, str, seen, depth - 1); + else + str << "(nullptr)"; + str << " "; + } + str << "]"; + } + break; + case nThunk: + if (!v.isBlackhole()) { + str << ""; + } else { + // Although we know for sure that it's going to be an infinite recursion + // when this value is accessed _in the current context_, it's likely + // that the user will misinterpret a simpler «infinite recursion» output + // as a definitive statement about the value, while in fact it may be + // a valid value after `builtins.trace` and perhaps some other steps + // have completed. + str << "«potential infinite recursion»"; + } + break; + case nFunction: + if (v.isLambda()) { + str << ""; + } else if (v.isPrimOp()) { + str << ""; + } else if (v.isPrimOpApp()) { + str << ""; + } + break; + case nExternal: + str << *v.external; + break; + case nFloat: + str << v.fpoint; + break; + default: + printError("Nix evaluator internal error: printAmbiguous: invalid value type"); + abort(); + } +} + +} diff --git a/src/libexpr/print-ambiguous.hh b/src/libexpr/print-ambiguous.hh new file mode 100644 index 000000000..50c260a9b --- /dev/null +++ b/src/libexpr/print-ambiguous.hh @@ -0,0 +1,24 @@ +#pragma once + +#include "value.hh" + +namespace nix { + +/** + * Print a value in the deprecated format used by `nix-instantiate --eval` and + * `nix-env` (for manifests). + * + * This output can't be changed because it's part of the `nix-instantiate` API, + * but it produces ambiguous output; unevaluated thunks and lambdas (and a few + * other types) are printed as Nix path syntax like ``. + * + * See: https://github.com/NixOS/nix/issues/9730 + */ +void printAmbiguous( + Value &v, + const SymbolTable &symbols, + std::ostream &str, + std::set *seen, + int depth); + +} diff --git a/src/nix-env/user-env.cc b/src/nix-env/user-env.cc index 3d07cab7a..973b6ee2b 100644 --- a/src/nix-env/user-env.cc +++ b/src/nix-env/user-env.cc @@ -108,8 +108,7 @@ bool createUserEnv(EvalState & state, DrvInfos & elems, environment. */ auto manifestFile = ({ std::ostringstream str; - std::set seen; - printAmbiguous(manifest, state.symbols, str, &seen, std::numeric_limits::max()); + printAmbiguous(manifest, state.symbols, str, nullptr, std::numeric_limits::max()); // TODO with C++20 we can use str.view() instead and avoid copy. std::string str2 = str.str(); StringSource source { str2 }; diff --git a/src/nix-instantiate/nix-instantiate.cc b/src/nix-instantiate/nix-instantiate.cc index 9b36dccc6..87bc986e8 100644 --- a/src/nix-instantiate/nix-instantiate.cc +++ b/src/nix-instantiate/nix-instantiate.cc @@ -1,9 +1,11 @@ #include "globals.hh" +#include "print-ambiguous.hh" #include "shared.hh" #include "eval.hh" #include "eval-inline.hh" #include "get-drvs.hh" #include "attr-path.hh" +#include "signals.hh" #include "value-to-xml.hh" #include "value-to-json.hh" #include "store-api.hh" @@ -24,7 +26,6 @@ static int rootNr = 0; enum OutputKind { okPlain, okXML, okJSON }; - void processExpr(EvalState & state, const Strings & attrPaths, bool parseOnly, bool strict, Bindings & autoArgs, bool evalOnly, OutputKind output, bool location, Expr * e) @@ -56,7 +57,8 @@ void processExpr(EvalState & state, const Strings & attrPaths, std::cout << std::endl; } else { if (strict) state.forceValueDeep(vRes); - vRes.print(state, std::cout); + std::set seen; + printAmbiguous(vRes, state.symbols, std::cout, &seen, std::numeric_limits::max()); std::cout << std::endl; } } else { diff --git a/tests/functional/lang/eval-okay-print.exp b/tests/functional/lang/eval-okay-print.exp index aa1b2379e..0d960fb70 100644 --- a/tests/functional/lang/eval-okay-print.exp +++ b/tests/functional/lang/eval-okay-print.exp @@ -1 +1 @@ -[ null «primop toString» «partially applied primop deepSeq» «lambda @ /pwd/lang/eval-okay-print.nix:1:61» [ [ «repeated» ] ] ] +[ null [ [ «repeated» ] ] ]