r367632 - [DirectoryWatcher] Relax assumption to prevent test flakiness

[Jan Korous via cfe-commits]

Author: jkorous
Date: Thu Aug  1 16:24:30 2019
New Revision: 367632

URL: http://llvm.org/viewvc/llvm-project?rev=367632&view=rev
Log:
[DirectoryWatcher] Relax assumption to prevent test flakiness

Modified:
    cfe/trunk/lib/DirectoryWatcher/mac/DirectoryWatcher-mac.cpp
    cfe/trunk/unittests/DirectoryWatcher/DirectoryWatcherTest.cpp

Modified: cfe/trunk/lib/DirectoryWatcher/mac/DirectoryWatcher-mac.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/DirectoryWatcher/mac/DirectoryWatcher-mac.cpp?rev=367632&r1=367631&r2=367632&view=diff
==============================================================================
--- cfe/trunk/lib/DirectoryWatcher/mac/DirectoryWatcher-mac.cpp (original)
+++ cfe/trunk/lib/DirectoryWatcher/mac/DirectoryWatcher-mac.cpp Thu Aug  1 16:24:30 2019
@@ -25,6 +25,24 @@ static void stopFSEventStream(FSEventStr
 
 namespace {
 
+/// This implementation is based on FSEvents API which implementation is
+/// aggressively coallescing events. This can manifest as duplicate events.
+///
+/// For example this scenario has been observed:
+///
+/// create foo/bar
+/// sleep 5 s
+/// create DirectoryWatcherMac for dir foo
+/// receive notification: bar EventKind::Modified
+/// sleep 5 s
+/// modify foo/bar
+/// receive notification: bar EventKind::Modified
+/// receive notification: bar EventKind::Modified
+/// sleep 5 s
+/// delete foo/bar
+/// receive notification: bar EventKind::Modified
+/// receive notification: bar EventKind::Modified
+/// receive notification: bar EventKind::Removed
 class DirectoryWatcherMac : public clang::DirectoryWatcher {
 public:
   DirectoryWatcherMac(

Modified: cfe/trunk/unittests/DirectoryWatcher/DirectoryWatcherTest.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/unittests/DirectoryWatcher/DirectoryWatcherTest.cpp?rev=367632&r1=367631&r2=367632&view=diff
==============================================================================
--- cfe/trunk/unittests/DirectoryWatcher/DirectoryWatcherTest.cpp (original)
+++ cfe/trunk/unittests/DirectoryWatcher/DirectoryWatcherTest.cpp Thu Aug  1 16:24:30 2019
@@ -377,7 +377,7 @@ TEST(DirectoryWatcherTest, DeleteFile) {
   VerifyingConsumer TestConsumer{
       {{EventKind::Modified, "a"}},
       {{EventKind::Removed, "a"}},
-      {{EventKind::Modified, "a"}}};
+      {{EventKind::Modified, "a"}, {EventKind::Removed, "a"}}};
 
   auto DW = DirectoryWatcher::create(
       fixture.TestWatchedDir,