patch = subprocess misses .coverage datafiles when subprocess is in another directory

[marcelotduarte]

Describe the bug
When the subprocess is in another directory (using cwd), patch = subprocess misses the coverage.

To Reproduce

1. Using Python 3.9 to 3.13
2. Using coverage 7.10.2 and 7.10.3a0.dev1 (from git+https://github.com/nedbat/coveragepy.git@d9683239c9ede7e292eb3d58e6051b184a5dcbf2)
3. commit to check: marcelotduarte/cx_Freeze@c5e210e
4. commit that fix: marcelotduarte/cx_Freeze@86913f5

Expected behavior
The .coverage data files must be stored together in the main directory.

Additional context
I'm replacing pytest-cov with pure coverage now that it supports patching in the subprocess. Previously, this wasn't possible. The change is quite simple (see 3), but I ran into this issue. I made the commits into my project separately to make it easier to show this bug.

In local testing on Linux, I was getting 56.36% coverage, but after the change, this coverage dropped to 47.03% (on GitHub, the coverage is 83% and then dropped to 62%).

After much testing, I discovered the problem and resolved it by copying the data files.

[nedbat]

This is fixed in commit 958e30e

[nedbat]

This is now released as part of coverage 7.10.3.

[marcelotduarte]

Thank you very much. I'll tell you what, it looks even better than expected. My tests are a bit complex, and I use venv in some of them. In conda-forge on Windows, these tests were showing some errors, whether due to disk usage, timeouts, or random errors. Now everything runs fine.