Flaky Windows error when running multiple rattler-build runs in parallel

[traversaro]

I am running multiple rattler-build invocation at the same time, and some time the build fails with:

Error:
  × Failed to resolve dependencies: failed to persist temporary repodata.json file
  ├─▶ failed to persist temporary repodata.json file
  ├─▶ failed to persist temporary file: Access is denied. (os error 5)
  ╰─▶ Access is denied. (os error 5)

restarting both rattler-build invocations at different times tipically solves this.

[wolfv]

Yes, I think the problem is the indexing in rattler-build. We should use the same file-locking mechanisms that we use e.g. in the repodata cache to make sure only one of the two processes writes a new repodata.json file.