fetchTree: Do not re-fetch paths already present

This commit is contained in:
Robert Hensing 2022-02-27 15:25:22 +01:00
parent 1c985428c4
commit 158280d8e9
3 changed files with 32 additions and 4 deletions

View File

@ -185,6 +185,13 @@ static void prim_fetchTree(EvalState & state, const Pos & pos, Value * * args, V
// FIXME: document
static RegisterPrimOp primop_fetchTree("fetchTree", 1, prim_fetchTree);
static void setStorePath(EvalState &state, const StorePath &storePath, Value &v) {
state.allowPath(storePath);
auto path = state.store->printStorePath(storePath);
v.mkString(path, PathSet({path}));
}
static void fetch(EvalState & state, const Pos & pos, Value * * args, Value & v,
const std::string & who, bool unpack, std::string name)
{
@ -203,6 +210,8 @@ static void fetch(EvalState & state, const Pos & pos, Value * * args, Value & v,
url = state.forceStringNoCtx(*attr.value, *attr.pos);
else if (n == "sha256")
expectedHash = newHashAllowEmpty(state.forceStringNoCtx(*attr.value, *attr.pos), htSHA256);
else if (n == "narHash")
expectedHash = newHashAllowEmpty(state.forceStringNoCtx(*attr.value, *attr.pos), htSHA256);
else if (n == "name")
name = state.forceStringNoCtx(*attr.value, *attr.pos);
else
@ -230,6 +239,20 @@ static void fetch(EvalState & state, const Pos & pos, Value * * args, Value & v,
if (evalSettings.pureEval && !expectedHash)
throw Error("in pure evaluation mode, '%s' requires a 'sha256' argument", who);
// early exit if pinned and already in the store
if (expectedHash && expectedHash->type == htSHA256) {
auto expectedPath =
unpack
? state.store->makeFixedOutputPath(FileIngestionMethod::Recursive, *expectedHash, name, {})
: state.store->makeFixedOutputPath(FileIngestionMethod::Flat, *expectedHash, name, {});
auto validPaths = state.store->queryValidPaths({expectedPath}, NoSubstitute);
if (!validPaths.empty()) {
setStorePath(state, expectedPath, v);
return;
}
}
auto storePath =
unpack
? fetchers::downloadTarball(state.store, *url, name, (bool) expectedHash).first.storePath
@ -244,10 +267,7 @@ static void fetch(EvalState & state, const Pos & pos, Value * * args, Value & v,
*url, expectedHash->to_string(Base32, true), hash.to_string(Base32, true));
}
state.allowPath(storePath);
auto path = state.store->printStorePath(storePath);
v.mkString(path, PathSet({path}));
setStorePath(state, storePath, v);
}
static void prim_fetchurl(EvalState & state, const Pos & pos, Value * * args, Value & v)

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@ -9,6 +9,10 @@ outPath=$(nix-build -vvvvv --expr 'import <nix/fetchurl.nix>' --argstr url file:
cmp $outPath fetchurl.sh
# Do not re-fetch paths already present.
outPath2=$(nix-build -vvvvv --expr 'import <nix/fetchurl.nix>' --argstr url file:///does-not-exist/must-remain-unused/fetchurl.sh --argstr sha256 $hash --no-out-link)
test "$outPath" == "$outPath2"
# Now using a base-64 hash.
clearStore

View File

@ -26,10 +26,14 @@ test_tarball() {
nix-build -o $TEST_ROOT/result '<foo>' -I foo=file://$tarball
nix-build -o $TEST_ROOT/result -E "import (fetchTarball file://$tarball)"
# Do not re-fetch paths already present
nix-build -o $TEST_ROOT/result -E "import (fetchTarball { url = file:///does-not-exist/must-remain-unused/$tarball; sha256 = \"$hash\"; })"
nix-build -o $TEST_ROOT/result -E "import (fetchTree file://$tarball)"
nix-build -o $TEST_ROOT/result -E "import (fetchTree { type = \"tarball\"; url = file://$tarball; })"
nix-build -o $TEST_ROOT/result -E "import (fetchTree { type = \"tarball\"; url = file://$tarball; narHash = \"$hash\"; })"
# Do not re-fetch paths already present
nix-build -o $TEST_ROOT/result -E "import (fetchTree { type = \"tarball\"; url = file:///does-not-exist/must-remain-unused/$tarball; narHash = \"$hash\"; })"
nix-build -o $TEST_ROOT/result -E "import (fetchTree { type = \"tarball\"; url = file://$tarball; narHash = \"sha256-xdKv2pq/IiwLSnBBJXW8hNowI4MrdZfW+SYqDQs7Tzc=\"; })" 2>&1 | grep 'NAR hash mismatch in input'
nix-instantiate --strict --eval -E "!((import (fetchTree { type = \"tarball\"; url = file://$tarball; narHash = \"$hash\"; })) ? submodules)" >&2