Mercurial > hg
view mercurial/revlogutils/concurrency_checker.py @ 47294:93a0abe098e7
revlog: avoid raising no-arg RevlogError for internal flow control
I'm about to make RevlogError require a `message` argument and this
code was failing. This patch refactors it to not raise an exception
for intra-function flow control.
Differential Revision: https://phab.mercurial-scm.org/D10740
author | Martin von Zweigbergk <martinvonz@google.com> |
---|---|
date | Tue, 18 May 2021 19:33:09 -0700 |
parents | e9901d01d135 |
children | 1c5810ce737e |
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from ..i18n import _ from .. import error def get_checker(ui, revlog_name=b'changelog'): """Get a function that checks file handle position is as expected. This is used to ensure that files haven't been modified outside of our knowledge (such as on a networked filesystem, if `hg debuglocks` was used, or writes to .hg that ignored locks happened). Due to revlogs supporting a concept of buffered, delayed, or diverted writes, we're allowing the files to be shorter than expected (the data may not have been written yet), but they can't be longer. Please note that this check is not perfect; it can't detect all cases (there may be false-negatives/false-OKs), but it should never claim there's an issue when there isn't (false-positives/false-failures). """ vpos = ui.config(b'debug', b'revlog.verifyposition.' + revlog_name) # Avoid any `fh.tell` cost if this isn't enabled. if not vpos or vpos not in [b'log', b'warn', b'fail']: return None def _checker(fh, fn, expected): if fh.tell() <= expected: return msg = _(b'%s: file cursor at position %d, expected %d') # Always log if we're going to warn or fail. ui.log(b'debug', msg + b'\n', fn, fh.tell(), expected) if vpos == b'warn': ui.warn((msg + b'\n') % (fn, fh.tell(), expected)) elif vpos == b'fail': raise error.RevlogError(msg % (fn, fh.tell(), expected)) return _checker