Incompatibility with hg-git 0.8 version due to rename detection

[fingolfin]

[ see also felipec/git#35 ]

hg-git recently added file rename detection. In particular, they add a mercurial "extra" field where they record the "source" of renames, and this new field ("hg-git-rename-source=git") break things.

Note that Mercurial 3.3 is incompatible with hg-git 0.7.0, and so once hg 3.3 is out, one will have to use it with hg-git newer than 0.7.0, which in turn means git-remote-hg users may run into this issue.

Relevant hg-git commit:
https://bitbucket.org/durin42/hg-git/commits/fffe8883960b7c45e0dfe597f3b79bd1f4824cbe

Typical diff (from first hg-git test, "executable bit")

--- output-hg   2015-01-13 15:46:17.000000000 +0000
+++ output-git  2015-01-13 15:46:18.000000000 +0000
@@ -1,8 +1,8 @@
-@  changeset:   2:04585efb2d7e9262381ab791282b68ceb33398d0
+@  changeset:   2:1efb93106a36bf71352ab04e769a3422522cf946
 |  bookmark:    master
 |  tag:         tip
 |  phase:       draft
-|  parent:      1:9d3aaf34d914c50354fbcca3a0c309351f159546
+|  parent:      1:d7cae8b1fdab97568ba5eca44ca2bf5a44d7c394
 |  parent:      -1:0000000000000000000000000000000000000000
 |  manifest:    2:51e6255d794f794a8c4e0f03edf264444e3c5ce7
 |  user:        A U Thor <[email protected]>
@@ -10,14 +10,13 @@
 |  files:       alpha
 |  extra:       branch=default
 |  extra:       committer=C O Mitter <[email protected]> 1167600600 -9000
-|  extra:       hg-git-rename-source=git
 |  description:
 |  clear executable bit
 |
 |
-o  changeset:   1:9d3aaf34d914c50354fbcca3a0c309351f159546
+o  changeset:   1:d7cae8b1fdab97568ba5eca44ca2bf5a44d7c394
 |  phase:       draft
-|  parent:      0:97e0f86af84c927e56ac1e6159b5b2386ac3e110
+|  parent:      0:362b656574c3c9e89fa7f2d7a943091dc93bce4d
 |  parent:      -1:0000000000000000000000000000000000000000
 |  manifest:    1:e4bf4ef5e9aea7a6a57573e533a5519bd062f144
 |  user:        A U Thor <[email protected]>
@@ -25,12 +24,11 @@
 |  files:       alpha
 |  extra:       branch=default
 |  extra:       committer=C O Mitter <[email protected]> 1167600600 -9000
-|  extra:       hg-git-rename-source=git
 |  description:
 |  set executable bit
 |
 |
-o  changeset:   0:97e0f86af84c927e56ac1e6159b5b2386ac3e110
+o  changeset:   0:362b656574c3c9e89fa7f2d7a943091dc93bce4d
    phase:       draft
    parent:      -1:0000000000000000000000000000000000000000
    parent:      -1:0000000000000000000000000000000000000000
@@ -40,7 +38,6 @@
    files+:      alpha
    extra:       branch=default
    extra:       committer=C O Mitter <[email protected]> 1167600600 -9000
-   extra:       hg-git-rename-source=git
    description:
    add alpha

In case it helps (probably not): The following naive and brainless patch (i.e. made without actually thinking about the issue) is, not surprisingly, not helping much. It causes some tests to pass, but causes issues in others.

diff --git a/git-remote-hg b/git-remote-hg
index 0d903e3..6900499 100755
--- a/git-remote-hg
+++ b/git-remote-hg
@@ -538,7 +538,8 @@ def export_ref(repo, name, kind, head):
                 extra_msg += "rename : %s => %s\n" % e

             for key, value in extra.iteritems():
-                if key in ('author', 'committer', 'encoding', 'message', 'branch', 'hg-git'):
+                if key in ('author', 'committer', 'encoding', 'message', 'branch',
+                           'hg-git', 'hg-git-rename-source'):
                     continue
                 else:
                     extra_msg += "extra : %s : %s\n" % (key, urllib.quote(value))
@@ -870,6 +871,9 @@ def parse_commit(parser):
                     extra[ek] = urllib.unquote(ev)
             data = data[:i]

+    if 'hg-git-rename-source' not in extra:
+        extra['hg-git-rename-source'] = 'git'   # HACK
+
     ctx = context.memctx(repo, (p1, p2), data,
             files.keys(), getfilectx,
             user, (date, tz), extra)