972432 - FileCopier creates directories corresponding to optional files

Status: NEW

(Firefox Build System :: General, defect)

Description

[Nick Alexander :nalexander [he/him]]

There is even a test documenting this behaviour in python/mozbuild/mozpack/test/test_copier.py.

The set of directories created is maintained by the base FileRegistry, which by design doesn't know anything about the files created.  One way to fix this ticket would be to have BaseFile declare is_optional, so that FileRegistry can interrogate its targets.

Comment 1

[Gregory Szorc [:gps]]

I'm not convinced this is a bug. "optional exists" really means "we expect it to exist eventually." We need to incur the cost of creating directories sometime. Might as well do it up front. If nothing else, this makes the code path for eventual file creation simpler, as they don't need to be concerned with directory creation.