Autogen: Ignore not existing source files in cmMakefile

Until CMake 3.10 a list of source files that had the AUTOUIC_OPTIONS property
populated was kept in `cmMakefile::QtUiFilesWithOptions`.  In the process to
remove all AUTOUIC related code from `cmMakefile` for CMake 3.10, the pre
filtered list was replaced by a loop in `cmQtAutoGeneratorInitializer` over
all source files in the `cmMakefile`.  This loop introduced the problem that
file paths were computed for source files that weren't in the target's sources
and that might not even have existed.  If the path for an unused and not
existing file was computed a `cmake::FATAL_ERROR` with the error message
"Cannot find source file:" was thrown nevertheless.
This caused some projects to fail in CMake 3.10.

This patch adds a test for path errors in the loops in
`cmQtAutoGeneratorInitializer` that iterate over all source files in a
`cmMakefile`. If a path error appears, the file is silently ignored.
If the file is part of the target's sources, the path error will still be
caught in the loop over all the target's sources.

This is the fix for CMake 3.10.1.

1 files changed, 17 insertions, 5 deletions

diff --git a/Source/cmQtAutoGeneratorInitializer.cxx b/Source/cmQtAutoGeneratorInitializer.cxx
index b02d872a42..89568c3879 100644
--- a/Source/cmQtAutoGeneratorInitializer.cxx
+++ b/Source/cmQtAutoGeneratorInitializer.cxx
@@ -361,11 +361,16 @@ static void SetupAcquireSkipFiles(cmQtAutoGenDigest const& digest,
 {
   // Read skip files from makefile sources
   {
-    const std::vector<cmSourceFile*>& allSources =
-      digest.Target->Makefile->GetSourceFiles();
-    for (cmSourceFile* sf : allSources) {
+    std::string pathError;
+    for (cmSourceFile* sf : digest.Target->Makefile->GetSourceFiles()) {
       // sf->GetExtension() is only valid after sf->GetFullPath() ...
-      std::string const& fPath = sf->GetFullPath();
+      // Since we're iterating over source files that might be not in the
+      // target we need to check for path errors (not existing files).
+      std::string const& fPath = sf->GetFullPath(&pathError);
+      if (!pathError.empty()) {
+        pathError.clear();
+        continue;
+      }
       cmSystemTools::FileFormat const fileType =
         cmSystemTools::GetFileFormat(sf->GetExtension().c_str());
       if (!(fileType == cmSystemTools::CXX_FILE_FORMAT) &&
@@ -540,9 +545,16 @@ static void SetupAutoTargetUic(cmQtAutoGenDigest const& digest,
     std::vector<std::vector<std::string>> uiFileOptions;
     {
       std::string const uiExt = "ui";
+      std::string pathError;
       for (cmSourceFile* sf : makefile->GetSourceFiles()) {
         // sf->GetExtension() is only valid after sf->GetFullPath() ...
-        std::string const& fPath = sf->GetFullPath();
+        // Since we're iterating over source files that might be not in the
+        // target we need to check for path errors (not existing files).
+        std::string const& fPath = sf->GetFullPath(&pathError);
+        if (!pathError.empty()) {
+          pathError.clear();
+          continue;
+        }
         if (sf->GetExtension() == uiExt) {
           std::string const absFile = cmSystemTools::GetRealPath(fPath);
           // Check if the file should be skipped