Mercurial > hg
view mercurial/minifileset.py @ 50316:87f0155d68aa stable
revlog: improve the robustness of the splitting process
The previous "in-place" splitting, preserving the splitting on transaction
failure had a couple of issue in case of transaction rollback:
- a race windows that could still lead to a crash and data loss
- it corrupted the `fncache`.
So instead, we use a new approach that we summarized as "we do a backup of the
inline revlog pre-split, and we restore this in case of failure".
To make readers live easier, we don't overwrite the inline index file until
transaction finalization. (once the transaction get into its finalization phase,
it is not expected to rollback, unless some crash happens).
To do so, we write the index of the split index in a temporary file that we use
until transaction finalization. We also keep a backup of the initial inline file
to be able to rollback the split if needed.
As a result, transaction rollback cancel the split and no longer corrupt
fncache. We also no longer have a small inconsistency windows where the
transaction could be unrecoverable.
author | Pierre-Yves David <pierre-yves.david@octobus.net> |
---|---|
date | Mon, 20 Mar 2023 11:52:17 +0100 |
parents | 6000f5b25c9b |
children |
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# minifileset.py - a simple language to select files # # Copyright 2017 Facebook, Inc. # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from .i18n import _ from . import ( error, fileset, filesetlang, pycompat, ) def _sizep(x): # i18n: "size" is a keyword expr = filesetlang.getstring(x, _(b"size requires an expression")) return fileset.sizematcher(expr) def _compile(tree): if not tree: raise error.ParseError(_(b"missing argument")) op = tree[0] if op == b'withstatus': return _compile(tree[1]) elif op in {b'symbol', b'string', b'kindpat'}: name = filesetlang.getpattern( tree, {b'path'}, _(b'invalid file pattern') ) if name.startswith(b'**'): # file extension test, ex. "**.tar.gz" ext = name[2:] for c in pycompat.bytestr(ext): if c in b'*{}[]?/\\': raise error.ParseError(_(b'reserved character: %s') % c) return lambda n, s: n.endswith(ext) elif name.startswith(b'path:'): # directory or full path test p = name[5:] # prefix pl = len(p) f = lambda n, s: n.startswith(p) and ( len(n) == pl or n[pl : pl + 1] == b'/' ) return f raise error.ParseError( _(b"unsupported file pattern: %s") % name, hint=_(b'paths must be prefixed with "path:"'), ) elif op in {b'or', b'patterns'}: funcs = [_compile(x) for x in tree[1:]] return lambda n, s: any(f(n, s) for f in funcs) elif op == b'and': func1 = _compile(tree[1]) func2 = _compile(tree[2]) return lambda n, s: func1(n, s) and func2(n, s) elif op == b'not': return lambda n, s: not _compile(tree[1])(n, s) elif op == b'func': symbols = { b'all': lambda n, s: True, b'none': lambda n, s: False, b'size': lambda n, s: _sizep(tree[2])(s), } name = filesetlang.getsymbol(tree[1]) if name in symbols: return symbols[name] raise error.UnknownIdentifier(name, symbols.keys()) elif op == b'minus': # equivalent to 'x and not y' func1 = _compile(tree[1]) func2 = _compile(tree[2]) return lambda n, s: func1(n, s) and not func2(n, s) elif op == b'list': raise error.ParseError( _(b"can't use a list in this context"), hint=_(b'see \'hg help "filesets.x or y"\''), ) raise error.ProgrammingError(b'illegal tree: %r' % (tree,)) def compile(text): """generate a function (path, size) -> bool from filter specification. "text" could contain the operators defined by the fileset language for common logic operations, and parenthesis for grouping. The supported path tests are '**.extname' for file extension test, and '"path:dir/subdir"' for prefix test. The ``size()`` predicate is borrowed from filesets to test file size. The predicates ``all()`` and ``none()`` are also supported. '(**.php & size(">10MB")) | **.zip | (path:bin & !path:bin/README)' for example, will catch all php files whose size is greater than 10 MB, all files whose name ends with ".zip", and all files under "bin" in the repo root except for "bin/README". """ tree = filesetlang.parse(text) tree = filesetlang.analyze(tree) tree = filesetlang.optimize(tree) return _compile(tree)