jest: sporadic "failed to cache transform results" error

[Stefan-Hanke]

I'm observing sporadic errorneous behaviour when running tests.
janosimas reported the same issue here: #175

Observation: For the last 4 occurrences, the error message is about file random.alea.js.
Not true - sporadic on any test file.

[Stefan-Hanke]

The issue is already reported: jestjs/jest#4444
There is a sort-of fix to use a patched version of graceful-fs.

[Stefan-Hanke]

I've applied patch-1 version of graceful-fs and it looks like it's working fine.

Would you mind a PR for this? We could leave this issue open to be reminded about jest behaviour, and eventually undo it should there ever be an official fix. Spoiler: It does not look like being fixed anytime soon, if ever.

Maybe I can apply that line at my machine locally only, so no source change is necessary. Is there a way to perform that, other than myself being really careful about package.json modifications?

[nicolodavis]

Let's go with patch-1 if you think it will fix the problem. This just involves adding:

"graceful-fs": "https://github.com/mekwall/node-graceful-fs.git#patch-1"

to package.json, correct?

Maybe I can apply that line at my machine locally only, so no source change is necessary. Is there a way to perform that, other than myself being really careful about package.json modifications?

I think this fix will benefit other developers here (including reducing the flakiness on the CI, although I think I've seen this error exactly once, so I wouldn't say it's a very prevalent problem), so I'm in favor of getting it in.

[Stefan-Hanke]

I witness this error on a regular basis, in case of PR #252 , I had a streak of 4-5 times where that error occurred.

[nicolodavis]

Hmm, I just ran npm installon a clean version of the repo and I see:

+        "graceful-fs": {
+         "version": "4.1.11",
+          "resolved": "https://registry.npmjs.org/graceful-fs/-/graceful-fs-4.1.11.tgz",
+          "integrity": "sha1-Dovf5NHduIVNZOBOp8AOKgJuVlg=",
+          "dev": true
+        },

in the diff of package-lock.json (under the dependencies section of jest).

I'm wondering if merely adding the patch to graceful-fs at the top level actually fixes it as a dependency for Jest, i.e. does Jest now use the patched version or does it continue to use the unpatched version?

[nicolodavis]

There is a separate question about committing this package-lock.json diff. Ideally running an npm install on a clean repo should result in no diffs.

[Stefan-Hanke]

I don't know. Searching for graceful-fs yields that all sorts of different versions are requested... (4.1.2, 4.1.4, 4.1.6, 4.1.11).

Looks like npm writes dependency information inside the package.json of the module itself, in case of graceful-js it looks OK though:

"_resolved": "git+https://github.com/mekwall/node-graceful-js.git#a10aa576f771d7cf3dfaee523f2e02d6eb11a89f",

, which is exactly HEAD of the patch-1 branch.

---

Unfortunately I continue to observe the error. Because of above I think npm resolved to the patch-1 version; if so, I'll just have to accept jest behaviour.

[Stefan-Hanke]

So I performed a fresch clone, run npm i, and there are a lot of diffs inside file package.lock. I'm not sure but looks like this is dependend on the npm version? I'm on npm version 6.4.0, node version 10.5.0.

Unfortunately the package.lock now looks a bit different, there is no mention of the patch-1 branch anymore, but only to the commit hash (albeit the right one).

[ksjogo]

Is this still needed? Having this as dependency breaks things with pnpm.

[nicolodavis]

Perhaps it is indeed time to evaluate if this can be removed. Thanks for looking into this @ksjogo!