CMP0026: Fix OLD behavior with file written during configure step

Refactoring in commit 60307c5056 (cmGeneratorTarget: Replace source
classifier implementation, 2017-04-07) accidentally regressed support
for CMP0026's OLD behavior in the case of a source file written by
project code during the configure step after getting a LOCATION.  We
should not perform full source classification until the generate step
because files written by the project's configure step may not exist yet.

Add special logic to support this case.  Add a test case for it.

Reported-by: David Stoup <david.stoup@kitware.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/Source/cmGeneratorTarget.cxx b/Source/cmGeneratorTarget.cxx
index 6779641..e84bf4e 100644
--- a/Source/cmGeneratorTarget.cxx
+++ b/Source/cmGeneratorTarget.cxx
@@ -947,6 +947,26 @@ void cmGeneratorTarget::GetSourceFiles(std::vector<std::string>& files,
 void cmGeneratorTarget::GetSourceFiles(std::vector<cmSourceFile*>& files,
                                        const std::string& config) const
 {
+  if (!this->GlobalGenerator->GetConfigureDoneCMP0026()) {
+    // Since we are still configuring not all sources may exist yet,
+    // so we need to avoid full source classification because that
+    // requires the absolute paths to all sources to be determined.
+    // Since this is only for compatibility with old policies that
+    // projects should not depend on anymore, just compute the files
+    // without memoizing them.
+    std::vector<std::string> srcs;
+    this->GetSourceFiles(srcs, config);
+    std::set<cmSourceFile*> emitted;
+    for (std::vector<std::string>::const_iterator i = srcs.begin();
+         i != srcs.end(); ++i) {
+      cmSourceFile* sf = this->Makefile->GetOrCreateSource(*i);
+      if (emitted.insert(sf).second) {
+        files.push_back(sf);
+      }
+    }
+    return;
+  }
+
   KindedSources const& kinded = this->GetKindedSources(config);
   files.reserve(kinded.Sources.size());
   for (std::vector<SourceAndKind>::const_iterator si = kinded.Sources.begin();