rhg: Propagate permission errors when finding a repository
The Rust standard library has a `Path::is_dir` method that returns false
for any I/O error (such as a permission error),
not just "No such file or directory".
Instead add an `is_dir` function that returns false for non-directories
and for "No such file or directory" errors, but propagates other I/O errors.
Differential Revision: https://phab.mercurial-scm.org/D11230
Create a repo, set the username to something more than 255 bytes, then run hg amend on it.
$ unset HGUSER
$ cat >> $HGRCPATH << EOF
> [ui]
> username = aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa <very.long.name@example.com>
> [extensions]
> amend =
> [experimental]
> evolution.createmarkers=True
> evolution.exchange=True
> EOF
$ hg init tmpa
$ cd tmpa
$ echo a > a
$ hg add
adding a
$ hg commit -m "Initial commit"
$ echo a >> a
$ hg amend 2>&1 | egrep -v '^(\*\*| )'
transaction abort!
rollback completed
Traceback (most recent call last):
*ProgrammingError: obsstore metadata value cannot be longer than 255 bytes (value "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa <very.long.name@example.com>" for key "user" is 285 bytes) (glob)