* fix(tools): say when format-on-write ran out of time
The 10s bound exists so a wedged formatter cannot hang a tool call, which
is right, and on expiry the unformatted write stood with nothing said. Every
other fallback here is a standing fact about the environment (toggle off, no
formatter for the extension, binary not installed) and is silent because
nothing is wrong. A deadline firing is not that: formatting was configured,
available and expected, and the file was written unformatted because the
machine was slow. Left silent, the caller believes it wrote canonical style
and finds out from a CI format check it cannot see, which is the failure
this feature exists to prevent.
The timeout is now reported on the write and edit summaries, naming the file
and the formatter. The caller cancelling and the formatter exiting non-zero
are deliberately not reported: the first is already surfaced as a cancelled
run, and the second usually means content the formatter could not parse,
which a write does not promise to fix.
The bound stays 10s rather than being raised. Raising it makes a wedged
formatter block longer, which is the thing the bound is for; what was
missing was knowing when it fired.
Closes#1022
* fix(tools): put the written bytes back when the formatter fails
These formatters edit in place, so one killed by the deadline, killed by
the caller, or exiting partway through its own rewrite can leave the target
truncated: neither the input nor the output. Returning the written bytes on
top of that left the tracker baseline and the diff preview describing a
file that is not on disk, so the next edit would compare against content the
file does not have. That is a worse failure than the missing formatting the
previous commit set out to disclose.
The failure paths write the bytes back, and when even that fails the user
hears about it, since it is their file. Written back unconditionally on that
path rather than only when the bytes differ: comparing first means reading
the file to find out, and a read that fails leaves the same ambiguity this
exists to remove.
The fixture is proven to damage the file on a throwaway copy, because a
successful restore erases the evidence from the real one. My first attempt
asserted that on the target itself, where it could only pass vacuously or
report the opposite of what it saw.
