D6643: convert: add a config option to help doing identity hg->hg conversion

valentin.gatienbaron (Valentin Gatien-Baron) phabricator at mercurial-scm.org
Sun Jul 14 15:17:01 EDT 2019


valentin.gatienbaron created this revision.
Herald added subscribers: mercurial-devel, mjpieters.
Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  I want to change the computation of the list of files modified by a
  commit. In principle, this would simply change a cache. But since this
  information is stored in commits rather than a cache, changing it
  means changing commit hashes (going forward).
  
  Some users rely on the convert extension from hg to hg not changing
  hashes when nothing changes (usually). Allow these users to preserve
  hashes despite changes to the changelog files computation by reusing
  these files lists when the manifest is unchanged (since these files
  list are derived from the manifest).

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D6643

AFFECTED FILES
  hgext/convert/__init__.py
  hgext/convert/common.py
  hgext/convert/hg.py
  hgext/lfs/__init__.py
  mercurial/configitems.py
  mercurial/localrepo.py
  tests/test-convert-identity.t
  tests/test-convert.t

CHANGE DETAILS

diff --git a/tests/test-convert.t b/tests/test-convert.t
--- a/tests/test-convert.t
+++ b/tests/test-convert.t
@@ -373,6 +373,11 @@
                     records the given string as a 'convert_source' extra value
                     on each commit made in the target repository. The default is
                     None.
+      convert.hg.preserve-hash
+                    only works with mercurial sources. Make convert prevent
+                    performance improvement to the list of modified files in
+                    commits when such an improvement would cause the hash of a
+                    commit to change. The default is False.
   
       All Destinations
       ################
diff --git a/tests/test-convert-identity.t b/tests/test-convert-identity.t
new file mode 100644
--- /dev/null
+++ b/tests/test-convert-identity.t
@@ -0,0 +1,40 @@
+Testing that convert.hg.preserve-hash=true can be used to make hg
+convert from hg repo to hg repo preserve hashes, even if the
+computation of the files list in commits change slightly between hg
+versions.
+
+  $ cat <<'EOF' >> "$HGRCPATH"
+  > [extensions]
+  > convert =
+  > EOF
+  $ cat <<'EOF' > changefileslist.py
+  > from mercurial import (changelog, extensions)
+  > def wrap(orig, clog, manifest, files, *args, **kwargs):
+  >   return orig(clog, manifest, ["a"], *args, **kwargs)
+  > def extsetup(ui):
+  >   extensions.wrapfunction(changelog.changelog, 'add', wrap)
+  > EOF
+
+  $ hg init repo
+  $ cd repo
+  $ echo a > a; hg commit -qAm a
+  $ echo b > a; hg commit -qAm b
+  $ hg up -qr 0; echo c > c; hg commit -qAm c
+  $ hg merge -qr 1
+  $ hg commit -m_ --config extensions.x=../changefileslist.py
+  $ hg log -r . -T '{node|short} {files|json}\n'
+  c085bbe93d59 ["a"]
+
+Now that we have a commit with a files list that's not what the
+current hg version would create, check that convert either fixes it or
+keeps it depending on config:
+
+  $ hg convert -q . ../convert
+  $ hg --cwd ../convert log -r tip -T '{node|short} {files|json}\n'
+  b7c4d4bbacd3 []
+  $ rm -rf ../convert
+
+  $ hg convert -q . ../convert --config convert.hg.preserve-hash=true
+  $ hg --cwd ../convert log -r tip -T '{node|short} {files|json}\n'
+  c085bbe93d59 ["a"]
+  $ rm -rf ../convert
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -2578,7 +2578,7 @@
         return ret
 
     @unfilteredmethod
-    def commitctx(self, ctx, error=False):
+    def commitctx(self, ctx, error=False, origctx=None):
         """Add a new revision to current repository.
         Revision information is passed via the context argument.
 
@@ -2586,6 +2586,12 @@
         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.
         """
 
         p1, p2 = ctx.p1(), ctx.p2()
@@ -2701,6 +2707,9 @@
                 filesadded = filesadded or None
                 filesremoved = filesremoved or None
 
+            if origctx and origctx.manifestnode() == mn:
+                files = origctx.files()
+
             # update changelog
             self.ui.note(_("committing changelog\n"))
             self.changelog.delayupdate(tr)
diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -291,6 +291,9 @@
 coreconfigitem('convert', 'hg.ignoreerrors',
     default=False,
 )
+coreconfigitem('convert', 'hg.preserve-hash',
+    default=False,
+)
 coreconfigitem('convert', 'hg.revs',
     default=None,
 )
diff --git a/hgext/lfs/__init__.py b/hgext/lfs/__init__.py
--- a/hgext/lfs/__init__.py
+++ b/hgext/lfs/__init__.py
@@ -227,9 +227,9 @@
 
     class lfsrepo(repo.__class__):
         @localrepo.unfilteredmethod
-        def commitctx(self, ctx, error=False):
+        def commitctx(self, ctx, error=False, origctx=None):
             repo.svfs.options['lfstrack'] = _trackedmatcher(self)
-            return super(lfsrepo, self).commitctx(ctx, error)
+            return super(lfsrepo, self).commitctx(ctx, error, origctx=origctx)
 
     repo.__class__ = lfsrepo
 
diff --git a/hgext/convert/hg.py b/hgext/convert/hg.py
--- a/hgext/convert/hg.py
+++ b/hgext/convert/hg.py
@@ -339,7 +339,11 @@
                                    phases.phasenames[commit.phase], 'convert')
 
             with self.repo.transaction("convert") as tr:
-                node = nodemod.hex(self.repo.commitctx(ctx))
+                if self.repo.ui.config('convert', 'hg.preserve-hash'):
+                    origctx = commit.ctx
+                else:
+                    origctx = None
+                node = nodemod.hex(self.repo.commitctx(ctx, origctx=origctx))
 
                 # If the node value has changed, but the phase is lower than
                 # draft, set it back to draft since it hasn't been exposed
@@ -591,7 +595,8 @@
                              extra=ctx.extra(),
                              sortkey=ctx.rev(),
                              saverev=self.saverev,
-                             phase=ctx.phase())
+                             phase=ctx.phase(),
+                             ctx=ctx)
 
     def numcommits(self):
         return len(self.repo)
diff --git a/hgext/convert/common.py b/hgext/convert/common.py
--- a/hgext/convert/common.py
+++ b/hgext/convert/common.py
@@ -114,7 +114,7 @@
 class commit(object):
     def __init__(self, author, date, desc, parents, branch=None, rev=None,
                  extra=None, sortkey=None, saverev=True, phase=phases.draft,
-                 optparents=None):
+                 optparents=None, ctx=None):
         self.author = author or 'unknown'
         self.date = date or '0 0'
         self.desc = desc
@@ -126,6 +126,7 @@
         self.sortkey = sortkey
         self.saverev = saverev
         self.phase = phase
+        self.ctx = ctx # for hg to hg conversions
 
 class converter_source(object):
     """Conversion source interface"""
diff --git a/hgext/convert/__init__.py b/hgext/convert/__init__.py
--- a/hgext/convert/__init__.py
+++ b/hgext/convert/__init__.py
@@ -439,6 +439,11 @@
     :convert.hg.sourcename: records the given string as a 'convert_source' extra
         value on each commit made in the target repository. The default is None.
 
+    :convert.hg.preserve-hash: only works with mercurial sources. Make convert
+        prevent performance improvement to the list of modified files in commits
+        when such an improvement would cause the hash of a commit to change.
+        The default is False.
+
     All Destinations
     ################
 



To: valentin.gatienbaron, #hg-reviewers
Cc: mjpieters, mercurial-devel


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