previous compilation was not self-contained

[Hixie]

While I was running flutter tests for the first time after merging my branch to tip of tree:

Compiler message:
Warning: Tried to initialize from a previous compilation (file:///usr/local/google/home/ianh/dev/flutter/packages/flutter/build/testfile.dill), but the file was not self-contained. This might be a bug.

The Dart team would greatly appreciate it if you would take a moment to report this problem at http://dartbug.com/new.
If you are comfortable with it, it would improve the chances of fixing any bug if you included the file file:///tmp/initialize_from.dillSZCOAG/initialize_from.dill.gz in your error report, but be aware that this file includes your source code.
Either way, you should probably delete the file so it doesn't use unnecessary disk space.

-> initialize_from.dill.gz

Compiler message:
01:03 +853 ~9: /usr/local/google/home/ianh/dev/flutter/packages/flutter/test/widgets/fade_transition_test.dart: FadeTransition Warning: Tried to initialize from a previous compilation (file:///usr/local/google/home/ianh/dev/flutter/packages/flutter/build/testfile.dill.track.dill), but the file was not self-contained. This might be a bug.

The Dart team would greatly appreciate it if you would take a moment to report this problem at http://dartbug.com/new.
If you are comfortable with it, it would improve the chances of fixing any bug if you included the file file:///tmp/initialize_from.dillTBDGNU/initialize_from.dill.gz in your error report, but be aware that this file includes your source code.
Either way, you should probably delete the file so it doesn't use unnecessary disk space.

-> initialize_from.dill.gz

[Hixie]

See also: #35129 #33760 #35476

[Hixie]

It happened a bunch more times for me in the same run of tests.

[jensjoha]

Looking at the first one only, it references "HttpStatus" in library "_http" which was moved in edca616#diff-9ca40264a25fa53a371cd7144bd23532.

So what happened was probably this: The dill file that was attempted initialized from was build on a platform before that commt, you then ran tests on a platform after that commit, where the class couldn't be found (in the expected place).

We certainly need a mechanism to catch stuff like this. I created #36032 for that.