Merge pull request #7911 from edolstra/revert-7689

Revert #7689

2 files changed, 18 insertions, 31 deletions

diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 3e37c7f60..21fc4d0fe 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -519,7 +519,6 @@ EvalState::EvalState(
     static_assert(sizeof(Env) <= 16, "environment must be <= 16 bytes");
 
     /* Initialise the Nix expression search path. */
-    evalSettings.nixPath.setDefault(evalSettings.getDefaultNixPath());
     if (!evalSettings.pureEval) {
         for (auto & i : _searchPath) addToSearchPath(i);
         for (auto & i : evalSettings.nixPath.get()) addToSearchPath(i);
@@ -2473,35 +2472,30 @@ std::ostream & operator << (std::ostream & str, const ExternalValueBase & v) {
 
 EvalSettings::EvalSettings()
 {
+    auto var = getEnv("NIX_PATH");
+    if (var) nixPath = parseNixPath(*var);
 }
 
-/* impure => NIX_PATH or a default path
- * restrict-eval => NIX_PATH
- * pure-eval => empty
- */
 Strings EvalSettings::getDefaultNixPath()
 {
-    if (pureEval)
-        return {};
-
-    auto var = getEnv("NIX_PATH");
-    if (var) {
-        return parseNixPath(*var);
-    } else if (restrictEval) {
-        return {};
-    } else {
-        Strings res;
-        auto add = [&](const Path & p, const std::optional<std::string> & s = std::nullopt) {
-            if (pathExists(p))
-                res.push_back(s ? *s + "=" + p : p);
-        };
+    Strings res;
+    auto add = [&](const Path & p, const std::string & s = std::string()) {
+        if (pathExists(p)) {
+            if (s.empty()) {
+                res.push_back(p);
+            } else {
+                res.push_back(s + "=" + p);
+            }
+        }
+    };
 
+    if (!evalSettings.restrictEval && !evalSettings.pureEval) {
         add(settings.useXDGBaseDirectories ? getStateDir() + "/nix/defexpr/channels" : getHome() + "/.nix-defexpr/channels");
         add(settings.nixStateDir + "/profiles/per-user/root/channels/nixpkgs", "nixpkgs");
         add(settings.nixStateDir + "/profiles/per-user/root/channels");
-
-        return res;
     }
+
+    return res;
 }
 
 bool EvalSettings::isPseudoUrl(std::string_view s)
diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index 2340ef67b..e4d5906bd 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -570,7 +570,7 @@ struct EvalSettings : Config
 {
     EvalSettings();
 
-    Strings getDefaultNixPath();
+    static Strings getDefaultNixPath();
 
     static bool isPseudoUrl(std::string_view s);
 
@@ -580,15 +580,8 @@ struct EvalSettings : Config
         "Whether builtin functions that allow executing native code should be enabled."};
 
     Setting<Strings> nixPath{
-        this, {}, "nix-path",
-        R"(
-          List of directories to be searched for `<...>` file references.
-
-          If [pure evaluation](#conf-pure-eval) is disabled,
-          this is initialised using the [`NIX_PATH`](@docroot@/command-ref/env-common.md#env-NIX_PATH)
-          environment variable, or, if it is unset and [restricted evaluation](#conf-restrict-eval)
-          is disabled, a default search path including the user's and `root`'s channels.
-        )"};
+        this, getDefaultNixPath(), "nix-path",
+        "List of directories to be searched for `<...>` file references."};
 
     Setting<bool> restrictEval{
         this, false, "restrict-eval",