From 5cbb618bb034ff24c85cdebd3860a50b366b1f11 Mon Sep 17 00:00:00 2001
From: Michael Bishop <cleverca22@gmail.com>
Date: Wed, 4 Mar 2020 22:22:20 -0400
Subject: [PATCH] log all ifd

---
 src/libexpr/eval.hh    |  5 ++++-
 src/libexpr/primops.cc | 19 +++++++++++--------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index e3eaed6d3be5..594ca455a271 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -308,7 +308,7 @@ public:
     /* Print statistics. */
     void printStats();
 
-    void realiseContext(const PathSet & context);
+    void realiseContext(const PathSet & context, const Pos &pos, const string & reason);
 
 private:
 
@@ -428,6 +428,9 @@ struct EvalSettings : Config
 
     Setting<bool> useEvalCache{this, true, "eval-cache",
         "Whether to use the flake evaluation cache."};
+
+    Setting<bool> logAllIFD{this, false, "log-all-ifd",
+        "Emit log messages for all imports from derivation at the 'info' log level"};
 };
 
 extern EvalSettings evalSettings;
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index 647b66ef660c..7a27c2a79b6f 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -33,7 +33,7 @@ namespace nix {
 InvalidPathError::InvalidPathError(const Path & path) :
     EvalError("path '%s' is not valid", path), path(path) {}
 
-void EvalState::realiseContext(const PathSet & context)
+void EvalState::realiseContext(const PathSet & context, const Pos &pos, const string & reason)
 {
     std::vector<DerivedPath::Built> drvs;
 
@@ -44,6 +44,9 @@ void EvalState::realiseContext(const PathSet & context)
             throw InvalidPathError(store->printStorePath(ctx));
         if (!outputName.empty() && ctx.isDerivation()) {
             drvs.push_back({ctx, {outputName}});
+            if (evalSettings.logAllIFD) {
+              printInfo("%1% importing from derivation %2% via %3%", pos, decoded.first, reason);
+            }
         }
     }
 
@@ -114,7 +117,7 @@ static void import(EvalState & state, const Pos & pos, Value & vPath, Value * vS
     Path path = state.coerceToPath(pos, vPath, context);
 
     try {
-        state.realiseContext(context);
+        state.realiseContext(context, pos, "scopedImport");
     } catch (InvalidPathError & e) {
         throw EvalError({
             .msg = hintfmt("cannot import '%1%', since path '%2%' is not valid", path, e.path),
@@ -284,7 +287,7 @@ void prim_importNative(EvalState & state, const Pos & pos, Value * * args, Value
     Path path = state.coerceToPath(pos, *args[0], context);
 
     try {
-        state.realiseContext(context);
+        state.realiseContext(context, pos, "importNative");
     } catch (InvalidPathError & e) {
         throw EvalError({
             .msg = hintfmt(
@@ -338,7 +341,7 @@ void prim_exec(EvalState & state, const Pos & pos, Value * * args, Value & v)
         commandArgs.emplace_back(state.coerceToString(pos, *elems[i], context, false, false));
     }
     try {
-        state.realiseContext(context);
+        state.realiseContext(context, pos, "exec");
     } catch (InvalidPathError & e) {
         throw EvalError({
             .msg = hintfmt("cannot execute '%1%', since path '%2%' is not valid",
@@ -1294,7 +1297,7 @@ static void prim_pathExists(EvalState & state, const Pos & pos, Value * * args,
     PathSet context;
     Path path = state.coerceToPath(pos, *args[0], context);
     try {
-        state.realiseContext(context);
+        state.realiseContext(context, pos, "pathExists");
     } catch (InvalidPathError & e) {
         throw EvalError({
             .msg = hintfmt(
@@ -1371,7 +1374,7 @@ static void prim_readFile(EvalState & state, const Pos & pos, Value * * args, Va
     PathSet context;
     Path path = state.coerceToPath(pos, *args[0], context);
     try {
-        state.realiseContext(context);
+        state.realiseContext(context, pos, "readFile");
     } catch (InvalidPathError & e) {
         throw EvalError({
             .msg = hintfmt("cannot read '%1%', since path '%2%' is not valid", path, e.path),
@@ -1422,7 +1425,7 @@ static void prim_findFile(EvalState & state, const Pos & pos, Value * * args, Va
         string path = state.coerceToString(pos, *i->value, context, false, false);
 
         try {
-            state.realiseContext(context);
+            state.realiseContext(context, pos, "findFile");
         } catch (InvalidPathError & e) {
             throw EvalError({
                 .msg = hintfmt("cannot find '%1%', since path '%2%' is not valid", path, e.path),
@@ -1478,7 +1481,7 @@ static void prim_readDir(EvalState & state, const Pos & pos, Value * * args, Val
     PathSet ctx;
     Path path = state.coerceToPath(pos, *args[0], ctx);
     try {
-        state.realiseContext(ctx);
+        state.realiseContext(ctx, pos, "readDir");
     } catch (InvalidPathError & e) {
         throw EvalError({
             .msg = hintfmt("cannot read '%1%', since path '%2%' is not valid", path, e.path),