mercurial/commit.py

commitctx: stop using weakref proxy for transaction

This weakref proxy was introduced in 2007 by 30d4d8985dd8.

If I understand it correctly, the logic at that time was relying on the
transaction destructor, triggered at garbage collection time to rollback failed
transaction. passing the object to sub function directly mean it would live in
the function scope and be trapped in the traceback on exception, leading to the
transaction rollback too late in some case.

Modern transaction usage use explicit opening and closing of transaction and no
longer rely on some internal reference counting details. So this weakref proxy
is no longer necessary. Absolutely no test are affected when we drop it.

# commit.py - fonction to perform commit
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import errno

from .i18n import _
from .node import (
    hex,
    nullid,
    nullrev,
)

from . import (
    context,
    mergestate,
    metadata,
    phases,
    scmutil,
    subrepoutil,
)


def commitctx(repo, ctx, error=False, origctx=None):
    """Add a new revision to the target repository.
    Revision information is passed via the context argument.

    ctx.files() should list all files involved in this commit, i.e.
    modified/added/removed files. On merge, it may be wider than the
    ctx.files() to be committed, since any file nodes derived directly
    from p1 or p2 are excluded from the committed ctx.files().

    origctx is for convert to work around the problem that bug
    fixes to the files list in changesets change hashes. For
    convert to be the identity, it can pass an origctx and this
    function will use the same files list when it makes sense to
    do so.
    """
    repo = repo.unfiltered()

    p1, p2 = ctx.p1(), ctx.p2()
    user = ctx.user()

    if repo.filecopiesmode == b'changeset-sidedata':
        writechangesetcopy = True
        writefilecopymeta = True
        writecopiesto = None
    else:
        writecopiesto = repo.ui.config(b'experimental', b'copies.write-to')
        writefilecopymeta = writecopiesto != b'changeset-only'
        writechangesetcopy = writecopiesto in (
            b'changeset-only',
            b'compatibility',
        )
    p1copies, p2copies = None, None
    if writechangesetcopy:
        p1copies = ctx.p1copies()
        p2copies = ctx.p2copies()
    filesadded, filesremoved = None, None
    with repo.lock(), repo.transaction(b"commit") as tr:
        if ctx.manifestnode():
            # reuse an existing manifest revision
            repo.ui.debug(b'reusing known manifest\n')
            mn = ctx.manifestnode()
            files = ctx.files()
            if writechangesetcopy:
                filesadded = ctx.filesadded()
                filesremoved = ctx.filesremoved()
        elif not ctx.files():
            repo.ui.debug(b'reusing manifest from p1 (no file change)\n')
            mn = p1.manifestnode()
            files = []
        else:
            m1ctx = p1.manifestctx()
            m2ctx = p2.manifestctx()
            mctx = m1ctx.copy()

            m = mctx.read()
            m1 = m1ctx.read()
            m2 = m2ctx.read()

            # check in files
            added = []
            filesadded = []
            removed = list(ctx.removed())
            touched = []
            linkrev = len(repo)
            repo.ui.note(_(b"committing files:\n"))
            uipathfn = scmutil.getuipathfn(repo)
            for f in sorted(ctx.modified() + ctx.added()):
                repo.ui.note(uipathfn(f) + b"\n")
                try:
                    fctx = ctx[f]
                    if fctx is None:
                        removed.append(f)
                    else:
                        added.append(f)
                        m[f], is_touched = _filecommit(
                            repo, fctx, m1, m2, linkrev, tr, writefilecopymeta,
                        )
                        if is_touched:
                            touched.append(f)
                            if writechangesetcopy and is_touched == 'added':
                                filesadded.append(f)
                        m.setflag(f, fctx.flags())
                except OSError:
                    repo.ui.warn(_(b"trouble committing %s!\n") % uipathfn(f))
                    raise
                except IOError as inst:
                    errcode = getattr(inst, 'errno', errno.ENOENT)
                    if error or errcode and errcode != errno.ENOENT:
                        repo.ui.warn(
                            _(b"trouble committing %s!\n") % uipathfn(f)
                        )
                    raise

            # update manifest
            removed = [f for f in removed if f in m1 or f in m2]
            drop = sorted([f for f in removed if f in m])
            for f in drop:
                del m[f]
            if p2.rev() != nullrev:
                rf = metadata.get_removal_filter(ctx, (p1, p2, m1, m2))
                removed = [f for f in removed if not rf(f)]

            touched.extend(removed)

            if writechangesetcopy:
                filesremoved = removed

            files = touched
            md = None
            if not files:
                # if no "files" actually changed in terms of the changelog,
                # try hard to detect unmodified manifest entry so that the
                # exact same commit can be reproduced later on convert.
                md = m1.diff(m, scmutil.matchfiles(repo, ctx.files()))
            if not files and md:
                repo.ui.debug(
                    b'not reusing manifest (no file change in '
                    b'changelog, but manifest differs)\n'
                )
            if files or md:
                repo.ui.note(_(b"committing manifest\n"))
                # we're using narrowmatch here since it's already applied at
                # other stages (such as dirstate.walk), so we're already
                # ignoring things outside of narrowspec in most cases. The
                # one case where we might have files outside the narrowspec
                # at this point is merges, and we already error out in the
                # case where the merge has files outside of the narrowspec,
                # so this is safe.
                mn = mctx.write(
                    tr,
                    linkrev,
                    p1.manifestnode(),
                    p2.manifestnode(),
                    added,
                    drop,
                    match=repo.narrowmatch(),
                )
            else:
                repo.ui.debug(
                    b'reusing manifest from p1 (listed files '
                    b'actually unchanged)\n'
                )
                mn = p1.manifestnode()

        if writecopiesto == b'changeset-only':
            # If writing only to changeset extras, use None to indicate that
            # no entry should be written. If writing to both, write an empty
            # entry to prevent the reader from falling back to reading
            # filelogs.
            p1copies = p1copies or None
            p2copies = p2copies or None
            filesadded = filesadded or None
            filesremoved = filesremoved or None

        if origctx and origctx.manifestnode() == mn:
            files = origctx.files()

        # update changelog
        repo.ui.note(_(b"committing changelog\n"))
        repo.changelog.delayupdate(tr)
        n = repo.changelog.add(
            mn,
            files,
            ctx.description(),
            tr,
            p1.node(),
            p2.node(),
            user,
            ctx.date(),
            ctx.extra().copy(),
            p1copies,
            p2copies,
            filesadded,
            filesremoved,
        )
        xp1, xp2 = p1.hex(), p2 and p2.hex() or b''
        repo.hook(
            b'pretxncommit', throw=True, node=hex(n), parent1=xp1, parent2=xp2,
        )
        # set the new commit is proper phase
        targetphase = subrepoutil.newcommitphase(repo.ui, ctx)
        if targetphase:
            # retract boundary do not alter parent changeset.
            # if a parent have higher the resulting phase will
            # be compliant anyway
            #
            # if minimal phase was 0 we don't need to retract anything
            phases.registernew(repo, tr, targetphase, [n])
        return n


def _filecommit(
    repo, fctx, manifest1, manifest2, linkrev, tr, includecopymeta,
):
    """
    commit an individual file as part of a larger transaction

    input:

        fctx:       a file context with the content we are trying to commit
        manifest1:  manifest of changeset first parent
        manifest2:  manifest of changeset second parent
        linkrev:    revision number of the changeset being created
        tr:         current transation
        individual: boolean, set to False to skip storing the copy data
                    (only used by the Google specific feature of using
                    changeset extra as copy source of truth).

    output: (filenode, touched)

        filenode: the filenode that should be used by this changeset
        touched:  one of: None (mean untouched), 'added' or 'modified'
    """

    fname = fctx.path()
    fparent1 = manifest1.get(fname, nullid)
    fparent2 = manifest2.get(fname, nullid)
    touched = None
    if fparent1 == fparent2 == nullid:
        touched = 'added'

    if isinstance(fctx, context.filectx):
        # This block fast path most comparisons which are usually done. It
        # assumes that bare filectx is used and no merge happened, hence no
        # need to create a new file revision in this case.
        node = fctx.filenode()
        if node in [fparent1, fparent2]:
            repo.ui.debug(b'reusing %s filelog entry\n' % fname)
            if (
                fparent1 != nullid and manifest1.flags(fname) != fctx.flags()
            ) or (
                fparent2 != nullid and manifest2.flags(fname) != fctx.flags()
            ):
                touched = 'modified'
            return node, touched

    flog = repo.file(fname)
    meta = {}
    cfname = fctx.copysource()
    fnode = None

    if cfname and cfname != fname:
        # Mark the new revision of this file as a copy of another
        # file.  This copy data will effectively act as a parent
        # of this new revision.  If this is a merge, the first
        # parent will be the nullid (meaning "look up the copy data")
        # and the second one will be the other parent.  For example:
        #
        # 0 --- 1 --- 3   rev1 changes file foo
        #   \       /     rev2 renames foo to bar and changes it
        #    \- 2 -/      rev3 should have bar with all changes and
        #                      should record that bar descends from
        #                      bar in rev2 and foo in rev1
        #
        # this allows this merge to succeed:
        #
        # 0 --- 1 --- 3   rev4 reverts the content change from rev2
        #   \       /     merging rev3 and rev4 should use bar@rev2
        #    \- 2 --- 4        as the merge base
        #

        cnode = manifest1.get(cfname)
        newfparent = fparent2

        if manifest2:  # branch merge
            if fparent2 == nullid or cnode is None:  # copied on remote side
                if cfname in manifest2:
                    cnode = manifest2[cfname]
                    newfparent = fparent1

        # Here, we used to search backwards through history to try to find
        # where the file copy came from if the source of a copy was not in
        # the parent directory. However, this doesn't actually make sense to
        # do (what does a copy from something not in your working copy even
        # mean?) and it causes bugs (eg, issue4476). Instead, we will warn
        # the user that copy information was dropped, so if they didn't
        # expect this outcome it can be fixed, but this is the correct
        # behavior in this circumstance.

        if cnode:
            repo.ui.debug(b" %s: copy %s:%s\n" % (fname, cfname, hex(cnode)))
            if includecopymeta:
                meta[b"copy"] = cfname
                meta[b"copyrev"] = hex(cnode)
            fparent1, fparent2 = nullid, newfparent
        else:
            repo.ui.warn(
                _(
                    b"warning: can't find ancestor for '%s' "
                    b"copied from '%s'!\n"
                )
                % (fname, cfname)
            )

    elif fparent1 == nullid:
        fparent1, fparent2 = fparent2, nullid
    elif fparent2 != nullid:
        # is one parent an ancestor of the other?
        fparentancestors = flog.commonancestorsheads(fparent1, fparent2)
        if fparent1 in fparentancestors:
            fparent1, fparent2 = fparent2, nullid
        elif fparent2 in fparentancestors:
            fparent2 = nullid
        elif not fparentancestors:
            # TODO: this whole if-else might be simplified much more
            ms = mergestate.mergestate.read(repo)
            if (
                fname in ms
                and ms[fname] == mergestate.MERGE_RECORD_MERGED_OTHER
            ):
                fparent1, fparent2 = fparent2, nullid

    # is the file changed?
    text = fctx.data()
    if fparent2 != nullid or meta or flog.cmp(fparent1, text):
        if touched is None:  # do not overwrite added
            touched = 'modified'
        fnode = flog.add(text, meta, tr, linkrev, fparent1, fparent2)
    # are just the flags changed during merge?
    elif fname in manifest1 and manifest1.flags(fname) != fctx.flags():
        touched = 'modified'
        fnode = fparent1
    else:
        fnode = fparent1
    return fnode, touched