[CAS] Improve error message when module cache key is missing

clang/lib/Frontend/CompileJobCacheKey.cpp

@@ -364,12 +364,7 @@ Error clang::printCompileJobCacheKey(ObjectStore &CAS, const CASID &Key,
   if (!H)
     return H.takeError();
   TreeSchema Schema(CAS);
-  if (!Schema.isNode(*H)) {
-    std::string ErrStr;
-    llvm::raw_string_ostream Err(ErrStr);
-    Err << "expected cache key to be a CAS tree; got ";
-    H->getID().print(Err);
-    return createStringError(inconvertibleErrorCode(), Err.str());
-  }
+  if (!Schema.isNode(*H))
+    return createStringError("unexpected cache key schema");
   return ::printCompileJobCacheKey(CAS, *H, OS);
 }

clang/lib/Frontend/CompilerInstance.cpp

@@ -2591,11 +2591,15 @@ static bool addCachedModuleFileToInMemoryCache(
     if (!Value) {
       Diag << Value.takeError();
     } else {
-      std::string ErrStr("no such entry in action cache; expected compile:\n");
+      std::string ErrStr("module file is not available in the CAS; expected to "
+                         "be produced by:\n");
       llvm::raw_string_ostream Err(ErrStr);
-      if (auto E = printCompileJobCacheKey(CAS, *ID, Err))
-        Diag << std::move(E);
-      else
+      if (auto E = printCompileJobCacheKey(CAS, *ID, Err)) {
+        // Ignore the error and skip printing the cache key. The cache key can
+        // be setup by a different compiler that is using an unknown schema.
+        llvm::consumeError(std::move(E));
+        Diag << "module file is not available in the CAS";
+      } else
         Diag << Err.str();
     }
     return true;

clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp

@@ -667,10 +667,11 @@ static void checkCompileCacheKeyMatch(cas::ObjectStore &CAS,
     llvm::report_fatal_error(OldKey.takeError());
   SmallString<256> Err;
   llvm::raw_svector_ostream OS(Err);
-  OS << "Compile cache key for module changed; previously:";
+  OS << "Compile cache key for module changed; previously: "
+     << OldKey->toString() << ": ";
   if (auto E = printCompileJobCacheKey(CAS, *OldKey, OS))
     OS << std::move(E);
-  OS << "\nkey is now:";
+  OS << "\nkey is now: " << NewKey.toString() << ": ";
   if (auto E = printCompileJobCacheKey(CAS, NewKey, OS))
     OS << std::move(E);
   llvm::report_fatal_error(OS.str());

clang/test/CAS/fmodule-file-cache-key-errors.c

@@ -59,7 +59,7 @@
 // RUN:   -fcache-compile-job -Rcompile-job-cache &> %t/bad_key2.txt
 // RUN: cat %t/bad_key2.txt | FileCheck %s -check-prefix=BAD_KEY2
 
-// BAD_KEY2: error: CAS cannot load module with key '{{.*}}' from -fmodule-file-cache-key: cas object is not a valid cache key
+// BAD_KEY2: error: CAS cannot load module with key '{{.*}}' from -fmodule-file-cache-key: module file is not available in the CAS
 
 // == Build A
 
@@ -87,7 +87,7 @@
 // RUN:   -fcache-compile-job -Rcompile-job-cache &> %t/not_in_cache.txt
 // RUN: cat %t/not_in_cache.txt | FileCheck %s -check-prefix=NOT_IN_CACHE -DPREFIX=%/t
 
-// NOT_IN_CACHE: error: CAS cannot load module with key '{{.*}}' from -fmodule-file-cache-key: no such entry in action cache; expected compile:
+// NOT_IN_CACHE: error: CAS cannot load module with key '{{.*}}' from -fmodule-file-cache-key: module file is not available in the CAS; expected to be produced by:
 // NOT_IN_CACHE: command-line:
 // NOT_IN_CACHE:   -cc1
 // NOT_IN_CACHE: filesystem:

clang/test/ClangScanDeps/modules-cas-trees.c

@@ -42,7 +42,7 @@
 // Missing pcm in action cache
 // RUN: not %clang @%t/Left.rsp 2> %t/error.txt
 // RUN: cat %t/error.txt | FileCheck %s -check-prefix=MISSING
-// MISSING: error: CAS cannot load module with key '{{.*}}' from -fmodule-file-cache-key: no such entry in action cache
+// MISSING: error: CAS cannot load module with key '{{.*}}' from -fmodule-file-cache-key: module file is not available in the CAS
 
 // Build everything
 // RUN: %clang @%t/Top.rsp 2>&1 | FileCheck %s -check-prefix=CACHE-MISS