( )⚙ D12187 filemerge: when using in-memory merge, always put backup files in temp dir

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Differential D12187

filemerge: when using in-memory merge, always put backup files in temp dir
ClosedPublic

Authored by martinvonz on Feb 15 2022, 11:09 PM.

Details

Reviewers
Alphare
Group Reviewers
hg-reviewers
Commits
rHGc7dbfc363655: filemerge: when using in-memory merge, always put backup files in temp dir
Summary

Before calling a merge tool, we create a backup of the local side of
the merge. That file can be put in the working copy or in a temporary
directory, depending on the user's config. When we're merging in
memory, we don't want to write to the actual, on-disk working copy, so
we write the file to the in-memory working copy instead. However,
since we don't support external merge tools with in-memory merge, it
makes no difference where the file is actually stored (and if we ever
do add support for external merge tools, then the file clearly can't
live in the in-memory working-copy object anyway). So, since it
doesn't matter where the file is stored, we can simplify by always
putting them in the system's temp directory.

Diff Detail

Repository
rHG Mercurial
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default
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Revision Contents
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PathPackages
Mmercurial/filemerge.py (37 lines)

Diff 32225

mercurial/filemerge.py

} }
return { return {
b"l": b" [%s]" % labels[0], b"l": b" [%s]" % labels[0],
b"o": b" [%s]" % labels[1], b"o": b" [%s]" % labels[1],
} }
def _makebackup(repo, ui, wctx, fcd): def _makebackup(repo, ui, fcd):
"""Makes and returns a filectx-like object for ``fcd``'s backup file. """Makes and returns a filectx-like object for ``fcd``'s backup file.
In addition to preserving the user's pre-existing modifications to `fcd` In addition to preserving the user's pre-existing modifications to `fcd`
(if any), the backup is used to undo certain premerges, confirm whether a (if any), the backup is used to undo certain premerges, confirm whether a
merge changed anything, and determine what line endings the new file should merge changed anything, and determine what line endings the new file should
have. have.
Backups only need to be written once since their content doesn't change Backups only need to be written once since their content doesn't change
afterwards. afterwards.
""" """
if fcd.isabsent(): if fcd.isabsent():
return None return None
# TODO: Break this import cycle somehow. (filectx -> ctx -> fileset -> # TODO: Break this import cycle somehow. (filectx -> ctx -> fileset ->
# merge -> filemerge). (I suspect the fileset import is the weakest link) # merge -> filemerge). (I suspect the fileset import is the weakest link)
from . import context from . import context
backup = scmutil.backuppath(ui, repo, fcd.path())
inworkingdir = backup.startswith(repo.wvfs.base) and not backup.startswith(
repo.vfs.base
)
if isinstance(fcd, context.overlayworkingfilectx) and inworkingdir:
# If the backup file is to be in the working directory, and we're
# merging in-memory, we must redirect the backup to the memory context
# so we don't disturb the working directory.
relpath = backup[len(repo.wvfs.base) + 1 :]
wctx[relpath].write(fcd.data(), fcd.flags())
return wctx[relpath]
else:
# Otherwise, write to wherever path the user specified the backups
# should go. We still need to switch based on whether the source is
# in-memory so we can use the fast path of ``util.copy`` if both are
# on disk.
if isinstance(fcd, context.overlayworkingfilectx): if isinstance(fcd, context.overlayworkingfilectx):
util.writefile(backup, fcd.data()) # If we're merging in-memory, we're free to put the backup anywhere.
fd, backup = pycompat.mkstemp(b'hg-merge-backup')
with os.fdopen(fd, 'wb') as f:
f.write(fcd.data())
else: else:
backup = scmutil.backuppath(ui, repo, fcd.path())
a = _workingpath(repo, fcd) a = _workingpath(repo, fcd)
util.copyfile(a, backup) util.copyfile(a, backup)
# A arbitraryfilectx is returned, so we can run the same functions on
# the backup context regardless of where it lives.
return context.arbitraryfilectx(backup, repo=repo) return context.arbitraryfilectx(backup, repo=repo)
@contextlib.contextmanager @contextlib.contextmanager
def _maketempfiles(fco, fca, localpath, uselocalpath): def _maketempfiles(fco, fca, localpath, uselocalpath):
"""Writes out `fco` and `fca` as temporary files, and (if uselocalpath) """Writes out `fco` and `fca` as temporary files, and (if uselocalpath)
copies `localpath` to another temporary file, so an external merge tool may copies `localpath` to another temporary file, so an external merge tool may
use them. use them.
""" """
if onfailure: if onfailure:
if wctx.isinmemory(): if wctx.isinmemory():
raise error.InMemoryMergeConflictsError( raise error.InMemoryMergeConflictsError(
b'in-memory merge does not support merge conflicts' b'in-memory merge does not support merge conflicts'
) )
ui.warn(onfailure % fduipath) ui.warn(onfailure % fduipath)
return 1, False return 1, False
backup = _makebackup(repo, ui, wctx, fcd) backup = _makebackup(repo, ui, fcd)
r = 1 r = 1
try: try:
internalmarkerstyle = ui.config(b'ui', b'mergemarkers') internalmarkerstyle = ui.config(b'ui', b'mergemarkers')
if isexternal: if isexternal:
markerstyle = _toolstr(ui, tool, b'mergemarkers') markerstyle = _toolstr(ui, tool, b'mergemarkers')
else: else:
markerstyle = internalmarkerstyle markerstyle = internalmarkerstyle