Merge pull request #11194 from NixOS/backport-11086-to-2.23-maintenance

[Backport 2.23-maintenance] Eval cache: fix cache regressions

src/libcmd/installable-value.hh

@@ -66,7 +66,7 @@ struct ExtraPathInfoValue : ExtraPathInfo
 };
 
 /**
- * An Installable which corresponds a Nix langauge value, in addition to
+ * An Installable which corresponds a Nix language value, in addition to
  * a collection of \ref DerivedPath "derived paths".
  */
 struct InstallableValue : Installable

src/libexpr/eval-cache.cc

@@ -95,7 +95,7 @@ struct AttrDb
     {
         try {
             auto state(_state->lock());
-            if (!failed)
+            if (!failed && state->txn->active)
                 state->txn->commit();
             state->txn.reset();
         } catch (...) {

src/nix/develop.cc

@@ -696,7 +696,11 @@ struct CmdDevelop : Common, MixEnvironment
             }
         }
 
-        runProgramInStore(store, UseLookupPath::Use, shell, args, buildEnvironment.getSystem());
+        // Release our references to eval caches to ensure they are persisted to disk, because
+        // we are about to exec out of this process without running C++ destructors.
+        getEvalState()->evalCaches.clear();
+
+        execProgramInStore(store, UseLookupPath::Use, shell, args, buildEnvironment.getSystem());
 #endif
     }
 };

src/nix/env.cc

@@ -1,4 +1,5 @@
 #include "command.hh"
+#include "eval.hh"
 #include "run.hh"
 #include <queue>
 
@@ -99,7 +100,11 @@ struct CmdShell : InstallablesCommand, MixEnvironment
         for (auto & arg : command)
             args.push_back(arg);
 
-        runProgramInStore(store, UseLookupPath::Use, *command.begin(), args);
+        // Release our references to eval caches to ensure they are persisted to disk, because
+        // we are about to exec out of this process without running C++ destructors.
+        getEvalState()->evalCaches.clear();
+
+        execProgramInStore(store, UseLookupPath::Use, *command.begin(), args);
     }
 };
 

src/nix/fmt.cc

@@ -1,5 +1,6 @@
 #include "command.hh"
 #include "installable-value.hh"
+#include "eval.hh"
 #include "run.hh"
 
 using namespace nix;
@@ -49,7 +50,11 @@ struct CmdFmt : SourceExprCommand {
             }
         }
 
-        runProgramInStore(store, UseLookupPath::DontUse, app.program, programArgs);
+        // Release our references to eval caches to ensure they are persisted to disk, because
+        // we are about to exec out of this process without running C++ destructors.
+        evalState->evalCaches.clear();
+
+        execProgramInStore(store, UseLookupPath::DontUse, app.program, programArgs);
     };
 };
 

src/nix/run.cc

@@ -25,7 +25,7 @@ std::string chrootHelperName = "__run_in_chroot";
 
 namespace nix {
 
-void runProgramInStore(ref<Store> store,
+void execProgramInStore(ref<Store> store,
     UseLookupPath useLookupPath,
     const std::string & program,
     const Strings & args,
@@ -128,7 +128,11 @@ struct CmdRun : InstallableValueCommand
         Strings allArgs{app.program};
         for (auto & i : args) allArgs.push_back(i);
 
-        runProgramInStore(store, UseLookupPath::DontUse, app.program, allArgs);
+        // Release our references to eval caches to ensure they are persisted to disk, because
+        // we are about to exec out of this process without running C++ destructors.
+        state->evalCaches.clear();
+
+        execProgramInStore(store, UseLookupPath::DontUse, app.program, allArgs);
     }
 };
 

src/nix/run.hh

@@ -10,7 +10,7 @@ enum struct UseLookupPath {
     DontUse
 };
 
-void runProgramInStore(ref<Store> store,
+void execProgramInStore(ref<Store> store,
     UseLookupPath useLookupPath,
     const std::string & program,
     const Strings & args,