[rush] dependsOnAdditionalFiles with multiple entries gives inconsistent hashing

[ericprestemon]

Summary

dependsOnAdditionalFiles with multiple globs does not give consistent caching behavior

Repro steps

Putting 8 lines into dependsOnAdditionalFiles in our rush-project.common.json, our various projects would randomly get cache hits or not.

Expected result:

Consistent caching results.

Actual result:

We'd often see 30-70% caching rather than 100% as expected.

Details

Combining the 8 lines into one glob entry that matches the same files does not have the issue.

So the issue appears to be that the globs are processed (and the results inserted) in effectively random order.

The getAdditionalFilesFromRushProjectConfigurationAsync function processing the globs with Async.forEachAsync and inserting in somewhat random order seems like the root cause.

One simple fix (that gets rid of the symptom at least) is to sort the files before hashing.

index 8eeaa5ed22..0568558d01 100644
--- a/libraries/rush-lib/src/logic/incremental/InputsSnapshot.ts
+++ b/libraries/rush-lib/src/logic/incremental/InputsSnapshot.ts
@@ -318,7 +318,9 @@ export class InputsSnapshot implements IInputsSnapshot {
         const additionalFilesForOperation: ReadonlySet<string> | undefined =
           record.additionalFilesByOperationName?.get(operationName);
         if (additionalFilesForOperation) {
-          for (const [filePath, hash] of this._resolveHashes(additionalFilesForOperation)) {
+          const sortedAdditionalFiles: string[] = Array.from(additionalFilesForOperation).sort();
+          for (const [filePath, hash] of this._resolveHashes(sortedAdditionalFiles)) {
             hashes.set(filePath, hash);
           }
         }

This doesn't fix the fact that insert order is non-deterministic, it just works around it.

Also it changes the existing hash order unnecessarily. That feels wrong so I didn't just submit the above as a PR.

Making the inserts into the list of files be deterministically ordered would be a more complex change.

Standard questions

Please answer these questions to help us investigate your issue more quickly:

Question	Answer
@microsoft/rush globally installed version?	5.153.1
rushVersion from rush.json?	5.153.1
pnpmVersion, npmVersion, or yarnVersion from rush.json?	pnpm@9.15.9
(if pnpm) useWorkspaces from pnpm-config.json?	true
Operating system?	Mac
Would you consider contributing a PR?	Yes
Node.js version (node -v)?	22.17.0