Merge pull request #8762 from obsidiansystems/split-out-eval-settings

Move evaluator settings (type and global) to separate file/header

1 files changed, 98 insertions, 0 deletions

diff --git a/src/libexpr/eval-settings.hh b/src/libexpr/eval-settings.hh
new file mode 100644
index 000000000..043af6cab
--- /dev/null
+++ b/src/libexpr/eval-settings.hh
@@ -0,0 +1,98 @@
+#pragma once
+#include "config.hh"
+
+namespace nix {
+
+struct EvalSettings : Config
+{
+    EvalSettings();
+
+    static Strings getDefaultNixPath();
+
+    static bool isPseudoUrl(std::string_view s);
+
+    static std::string resolvePseudoUrl(std::string_view url);
+
+    Setting<bool> enableNativeCode{this, false, "allow-unsafe-native-code-during-evaluation",
+        "Whether builtin functions that allow executing native code should be enabled."};
+
+    Setting<Strings> nixPath{
+        this, getDefaultNixPath(), "nix-path",
+        R"(
+          List of directories to be searched for `<...>` file references
+
+          In particular, outside of [pure evaluation mode](#conf-pure-evaluation), this determines the value of
+          [`builtins.nixPath`](@docroot@/language/builtin-constants.md#builtins-nixPath).
+        )"};
+
+    Setting<bool> restrictEval{
+        this, false, "restrict-eval",
+        R"(
+          If set to `true`, the Nix evaluator will not allow access to any
+          files outside of the Nix search path (as set via the `NIX_PATH`
+          environment variable or the `-I` option), or to URIs outside of
+          [`allowed-uris`](../command-ref/conf-file.md#conf-allowed-uris).
+          The default is `false`.
+        )"};
+
+    Setting<bool> pureEval{this, false, "pure-eval",
+        R"(
+          Pure evaluation mode ensures that the result of Nix expressions is fully determined by explicitly declared inputs, and not influenced by external state:
+
+          - Restrict file system and network access to files specified by cryptographic hash
+          - Disable [`bultins.currentSystem`](@docroot@/language/builtin-constants.md#builtins-currentSystem) and [`builtins.currentTime`](@docroot@/language/builtin-constants.md#builtins-currentTime)
+        )"
+        };
+
+    Setting<bool> enableImportFromDerivation{
+        this, true, "allow-import-from-derivation",
+        R"(
+          By default, Nix allows you to `import` from a derivation, allowing
+          building at evaluation time. With this option set to false, Nix will
+          throw an error when evaluating an expression that uses this feature,
+          allowing users to ensure their evaluation will not require any
+          builds to take place.
+        )"};
+
+    Setting<Strings> allowedUris{this, {}, "allowed-uris",
+        R"(
+          A list of URI prefixes to which access is allowed in restricted
+          evaluation mode. For example, when set to
+          `https://github.com/NixOS`, builtin functions such as `fetchGit` are
+          allowed to access `https://github.com/NixOS/patchelf.git`.
+        )"};
+
+    Setting<bool> traceFunctionCalls{this, false, "trace-function-calls",
+        R"(
+          If set to `true`, the Nix evaluator will trace every function call.
+          Nix will print a log message at the "vomit" level for every function
+          entrance and function exit.
+
+              function-trace entered undefined position at 1565795816999559622
+              function-trace exited undefined position at 1565795816999581277
+              function-trace entered /nix/store/.../example.nix:226:41 at 1565795253249935150
+              function-trace exited /nix/store/.../example.nix:226:41 at 1565795253249941684
+
+          The `undefined position` means the function call is a builtin.
+
+          Use the `contrib/stack-collapse.py` script distributed with the Nix
+          source code to convert the trace logs in to a format suitable for
+          `flamegraph.pl`.
+        )"};
+
+    Setting<bool> useEvalCache{this, true, "eval-cache",
+        "Whether to use the flake evaluation cache."};
+
+    Setting<bool> ignoreExceptionsDuringTry{this, false, "ignore-try",
+        R"(
+          If set to true, ignore exceptions inside 'tryEval' calls when evaluating nix expressions in
+          debug mode (using the --debugger flag). By default the debugger will pause on all exceptions.
+        )"};
+
+    Setting<bool> traceVerbose{this, false, "trace-verbose",
+        "Whether `builtins.traceVerbose` should trace its first argument when evaluated."};
+};
+
+extern EvalSettings evalSettings;
+
+}