Reject TARGET_PDB_FILE for imported targets instead of crashing

Reported-by: Justin Borodinsky <[email protected]>

Source/cmGeneratorExpressionNode.cxx

@@ -1600,6 +1600,13 @@ struct TargetFilesystemArtifactResultCreator<ArtifactPdbTag>
                             cmGeneratorExpressionContext *context,
                             const GeneratorExpressionContent *content)
   {
+    if (target->IsImported())
+      {
+      ::reportError(context, content->GetOriginalExpression(),
+                    "TARGET_PDB_FILE not allowed for IMPORTED targets.");
+      return std::string();
+      }
+
     std::string language = target->GetLinkerLanguage(context->Config);
 
     std::string pdbSupportVar = "CMAKE_" + language + "_LINKER_SUPPORTS_PDB";

Source/cmGeneratorTarget.cxx

@@ -1248,6 +1248,7 @@ void cmGeneratorTarget::ComputeLinkClosure(const std::string& config,
   UNORDERED_SET<std::string> languages;
   cmTarget::LinkImplementation const* impl =
                             this->Target->GetLinkImplementation(config);
+  assert(impl);
   for(std::vector<std::string>::const_iterator li = impl->Languages.begin();
       li != impl->Languages.end(); ++li)
     {

Tests/RunCMake/GeneratorExpression/ImportedTarget-TARGET_PDB_FILE-result.txt

@@ -0,0 +1 @@
+1

Tests/RunCMake/GeneratorExpression/ImportedTarget-TARGET_PDB_FILE-stderr.txt

@@ -0,0 +1,8 @@
+CMake Error at ImportedTarget-TARGET_PDB_FILE.cmake:2 \(add_custom_target\):
+  Error evaluating generator expression:
+
+    \$<TARGET_PDB_FILE:empty>
+
+  TARGET_PDB_FILE not allowed for IMPORTED targets.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)

Tests/RunCMake/GeneratorExpression/ImportedTarget-TARGET_PDB_FILE.cmake

@@ -0,0 +1,2 @@
+add_library(empty UNKNOWN IMPORTED)
+add_custom_target(custom COMMAND echo $<TARGET_PDB_FILE:empty>)

Tests/RunCMake/GeneratorExpression/RunCMakeTest.cmake

@@ -26,6 +26,7 @@ run_cmake(COMPILE_LANGUAGE-add_library)
 run_cmake(COMPILE_LANGUAGE-add_test)
 run_cmake(COMPILE_LANGUAGE-unknown-lang)
 
+run_cmake(ImportedTarget-TARGET_PDB_FILE)
 if(LINKER_SUPPORTS_PDB)
   run_cmake(NonValidTarget-TARGET_PDB_FILE)
   run_cmake(ValidTarget-TARGET_PDB_FILE)