Webpack skips changes to files when compilation is suspended

[vladar]

Bug report

What is the current behavior?

This is an issue with suspend and resume flow of Watching. The second and subsequent aggregated changes that occur after suspend are dismissed by webpack.

If the current behavior is a bug, please provide the steps to reproduce.

1. Call suspend.
2. Edit file1
3. Wait when aggregation timeout passes (and aggregated watchpack event fires)
4. Edit file2
5. Call resume.

What is the expected behavior?

The compilation contains changes from both file1 and file2

Actual result: only changes from file1 are applied. Changes to file2 are skipped by webpack.

I've opened a PR with a failing test that demonstrates the problem (and suggested fix): #12897

Other relevant information:
webpack version: latest (but also exists in v4 latest)
Node.js version: 12
Operating System: Windows
Additional tools: no

[alexander-akait]

Please prefer to use the one issue (#12882) to track all problems with suspend and resume, looks it is side effects of the one problem

[vladar]

No, those are actually different bugs (they hit different codepaths). Fixing one won't fix the other. That's why I've opened two issues. Also, they have quite different steps to reproduce.

[alexander-akait]

Fixed by #13399