From 087be7281a02a6d0e548ae56b910771837023d21 Mon Sep 17 00:00:00 2001
From: Shea Levy <shea@shealevy.com>
Date: Sun, 13 Jan 2019 10:33:15 -0500
Subject: [PATCH] Treat plain derivation paths in context as normal paths.

Previously, plain derivation paths in the string context (e.g. those
that arose from builtins.storePath on a drv file, not those that arose
from accessing .drvPath of a derivation) were treated somewhat like
derivaiton paths derived from .drvPath, except their dependencies
weren't recursively added to the input set. With this change, such
plain derivation paths are simply treated as paths and added to the
source inputs set accordingly, simplifying context handling code and
removing the inconsistency. If drvPath-like behavior is desired, the
.drv file can be imported and then .drvPath can be accessed.

This is a backwards-incompatibility, but storePath is never used on
drv files within nixpkgs and almost never used elsewhere.
---
 .gitignore             |  3 +++
 src/libexpr/primops.cc | 20 +++-----------------
 2 files changed, 6 insertions(+), 17 deletions(-)

diff --git a/.gitignore b/.gitignore
index 0f2f3dde..b75c5d48 100644
--- a/.gitignore
+++ b/.gitignore
@@ -81,6 +81,9 @@ perl/Makefile.config
 /tests/common.sh
 /tests/dummy
 /tests/result*
+/tests/restricted-innocent
+/tests/shell
+/tests/shell.drv
 
 # /tests/lang/
 /tests/lang/*.out
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index 60698f74..113ceaf2 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -687,21 +687,12 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
             }
         }
 
-        /* See prim_unsafeDiscardOutputDependency. */
-        else if (path.at(0) == '~')
-            drv.inputSrcs.insert(string(path, 1));
-
         /* Handle derivation outputs of the form ‘!<name>!<path>’. */
         else if (path.at(0) == '!') {
             std::pair<string, string> ctx = decodeContext(path);
             drv.inputDrvs[ctx.first].insert(ctx.second);
         }
 
-        /* Handle derivation contexts returned by
-           ‘builtins.storePath’. */
-        else if (isDerivation(path))
-            drv.inputDrvs[path] = state.store->queryDerivationOutputNames(path);
-
         /* Otherwise it's a source file. */
         else
             drv.inputSrcs.insert(path);
@@ -1004,13 +995,8 @@ static void prim_toFile(EvalState & state, const Pos & pos, Value * * args, Valu
     PathSet refs;
 
     for (auto path : context) {
-        if (path.at(0) == '=') path = string(path, 1);
-        if (isDerivation(path)) {
-            /* See prim_unsafeDiscardOutputDependency. */
-            if (path.at(0) != '~')
-                throw EvalError(format("in 'toFile': the file '%1%' cannot refer to derivation outputs, at %2%") % name % pos);
-            path = string(path, 1);
-        }
+        if (path.at(0) != '/')
+            throw EvalError(format("in 'toFile': the file '%1%' cannot refer to derivation outputs, at %2%") % name % pos);
         refs.insert(path);
     }
 
@@ -1823,7 +1809,7 @@ static void prim_unsafeDiscardOutputDependency(EvalState & state, const Pos & po
 
     PathSet context2;
     for (auto & p : context)
-        context2.insert(p.at(0) == '=' ? "~" + string(p, 1) : p);
+        context2.insert(p.at(0) == '=' ? string(p, 1) : p);
 
     mkString(v, s, context2);
 }