* fix(community): reserve Browserless capture names before publishing
Name selection and publication were two separate operations:
`_dedupe_output_name` probed with `Path.exists()` and then
`publish_bytes_atomically` ran `os.replace`, so two `web_capture` calls in the
same thread outputs directory could both settle on `report.png` before either
wrote, and the second publication replaced the first capture while both reported
success for the same artifact path (#6883). `web_capture_tool` runs the writer
through `asyncio.to_thread`, and same-second default names collide the same way
because the generated stem's timestamp has second resolution.
Claim the name instead of checking for it: an `O_CREAT | O_EXCL` open either
creates an empty placeholder or reports the name held, so the probe walk
(-1, -2, ... then the microsecond timestamp) is race-free. `_write_capture_output`
releases the placeholder when publication fails, catching BaseException so an
interruption also frees the name, and a failing unlink is logged rather than
allowed to mask the original error - the same error-masking family #6871 is
addressing in the shared publisher, which this change deliberately does not
touch.
When even the timestamped names are held, the function now raises instead of
returning a name it cannot own; returning one would reintroduce the silent
overwrite. `tests/test_browser_outputs_atomic.py` pins the publisher call as
source text, so its expectation moved to the new call shape in the same commit.
Refs #6883
* fix(community): open the reserved capture name with new-file permissions
An `os.open` without an explicit mode creates the file with `0o777 & ~umask`, and
`publish_bytes_atomically` preserves an existing destination's mode, so the
reservation added in the previous commit made every capture executable (`0o755`
under the usual umask) where main produced `0o666 & ~umask` (`0o644`) through the
publisher's new-file branch. Pass `0o666` explicitly and pin the mode against a
`Path.write_bytes` reference in the same directory, which is the permission the
publisher documents for new files.
Refs #6883
* fix(browserless): warn when capture reservation cleanup fails
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Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
* fix(browser): publish captured screenshots and fetches atomically
_write_screenshot and _write_capture_output wrote the final path with a truncating
write and then returned its name, so a failure part-way through left a partial
capture that the caller reported as saved - and the leftovers then made the dedupe
helper pick a new name for the next capture. Publish through a temporary file plus
os.replace.
* fix(browser): preserve permissions on atomic capture publication
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Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
