cached task overwrites modified top level files (that are outside of `src/`)

[harunurhan]

Describe the bug

To Reproduce
Steps to reproduce the behavior:

1. Define a package with a target and no inputs and outputs specified, and package needs to have some files under src/ folder and top level like jest.config.js
2. Run the task once (so it's cached)
3. Make a change to a top-level file
4. Re-run the same task (it should be skipped)
5. You will see that changes you made to the top level file are reverted after the cached/skipped task run. Observe that this isn't valid for files that starts with . like .eslintrc.js

Expected behavior

Cached task runs should not revert any changes by default. Although it can be worked around using inputs and outputs, it's a strange default behaviour.

Environment/Troubleshooting

[harunurhan]

Strange thing is that if I specify input: ["*"], everything works correctly but I don't understand how * glob could be the fix here.

• if <package>/src/foo.js changes, cache is invalidated (but HOW?)
• if <package>/.foorc.js changes, cache is invalidated
• if <package>/foo.js changes, cache is invalidated
• If <packages>/dist/foo.js changes, cache is NOT invalidated (which is what I want but still strange)

[kenotron]

I think the default behavior can be tweaked - I think in this case, output should subtract inputs from its tracking by default. I'm going to put a high priority label on this issue.

[kenotron]

I really would appreciate a small mini-repro-repo that I can use to target a fix here.

[kenotron]

https://github.com/kenotron/lage-bug-766

I cannot repro this issue...

[dobesv]

I was just seeing this as well, I ran lage and it undid changes to my source files. It doesn't seem like it has to be a top-level file, just some tasks are seemingly restoring old versions of source files from the cache.

[dobesv]

I think the problem is with this line of code here:

lage/packages/cache/src/providers/BackfillCacheProvider.ts

Line 79 in a2996cd

await cacheStorage.put(hash, target.outputs ?? this.options.cacheOptions.outputGlob ?? ["**/*"]);

It assumes that if ouputs is not set, it should treat everything in the folder as an output. This seems like a faulty assumption. Probably by default outputs should be considered empty, or possibly it could default to some "typical" outputs like ["dist/**", "build/**"]. However, empty seems like a better default to me.

[dobesv]

Possible fix over here:

#878