Buildbot: Only archive core dumps from unexpected crashes.

tools/testing/dart/test_progress.dart

Index: tools/testing/dart/test_progress.dart
diff --git a/tools/testing/dart/test_progress.dart b/tools/testing/dart/test_progress.dart
index d1af50c408c5fd3c8f0af620cdb3b4f9c0feca78..86557937fdaec5f5437607af3908dad2b47d0cf2 100644
--- a/tools/testing/dart/test_progress.dart
+++ b/tools/testing/dart/test_progress.dart
@@ -316,7 +316,7 @@ class TestOutcomeLogWriter extends EventListener {
 }
 
 class UnexpectedCrashDumpArchiver extends EventListener {
-  final archivedBinaries = new Set<String>();
+  final archivedBinaries = <String, String>{};
 
   void done(TestCase test) {
     if (test.unexpectedOutput &&
@@ -335,16 +335,27 @@ class UnexpectedCrashDumpArchiver extends EventListener {
         final binName = lastCommand.executable;
         final binFile = new File(binName);
         final binBaseName = new Path(binName).filename;
-        if (archivedBinaries.contains(binBaseName)) {
-          return;
-        }
-
-        if (binFile.existsSync()) {
+        if (!archivedBinaries.containsKey(binName) &&
+            binFile.existsSync()) {
           final mode = test.configuration['mode'];
           final arch = test.configuration['arch'];
-          TestUtils.copyFile(new Path(binName),
-              new Path("core.${mode}_${arch}_${binBaseName}"));
-          archivedBinaries.add(binBaseName);
+          final archived = "binary.${mode}_${arch}_${binBaseName}";
+          TestUtils.copyFile(new Path(binName), new Path(archived));
+          archivedBinaries[binName] = archived;
+        }
+
+        if (archivedBinaries.containsKey(binName)) {
+          // We have found and copied the binary.
+          var coredumpsList;
+          try {
+            coredumpsList =
+                new File('coredumps').openSync(mode: FileMode.APPEND);

[kustermann, 2017/01/20 14:56:55]

Instead of doing this for every test, how about opening it lazily and adding a
IOSink field.

You can use the 'void allDone() {}' callback to flush the stream and close the
file.

[Vyacheslav Egorov (Google), 2017/01/20 16:44:45]

I wanted to do it for each test so that even if test.dart runner crashes we
still have at least some things logged into the file. 

It's unlikely to matter - because there should be very few crashes anyway.

+            coredumpsList.writeStringSync(
+                "${test.displayName},${name},${archivedBinaries[binName]}\n");
+          } finally {
+            if (coredumpsList != null)

[kustermann, 2017/01/20 14:56:55]

You could as well move the 'new File(...') out of the "try {" and get rid of
this "if (coredumpsList != null)".

[Vyacheslav Egorov (Google), 2017/01/20 16:44:45]

I wanted to catch and ignore exceptions from openSync, but forgot to add that
line.

+              coredumpsList.close();
+          }
         }
       }
     }