--- a/vcssync/mozvcssync/cli.py
+++ b/vcssync/mozvcssync/cli.py
@@ -1,18 +1,24 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 from __future__ import absolute_import, unicode_literals
 
 import argparse
 import logging
+import subprocess
 import sys
 
+import hglib
+
+from .git2hg import (
+    linearize_git_repo_to_hg,
+)
 from .gitrewrite import (
     RewriteError,
 )
 from .gitrewrite.linearize import (
     linearize_git_repo,
 )
 
 
@@ -105,8 +111,64 @@ def linearize_git():
 
     if args.source_repo:
         kwargs['source_repo'] = args.source_repo
 
     try:
         linearize_git_repo(args.git_repo, args.ref, **kwargs)
     except RewriteError as e:
         logger.error('abort: %s' % str(e))
+
+
+def linearize_git_to_hg():
+    parser = argparse.ArgumentParser()
+    for args, kwargs in LINEARIZE_GIT_ARGS:
+        parser.add_argument(*args, **kwargs)
+
+    parser.add_argument('--hg', help='hg executable to use')
+    parser.add_argument('--move-to-subdir',
+                        help='Move the files in the Git repository under a '
+                             'different subdirection in the destination repo')
+    parser.add_argument('--copy-similarity', type=int, default=50,
+                        dest='similarity',
+                        help='File % similarity for it to be identified as a '
+                             'copy')
+    parser.add_argument('--find-copies-harder', action='store_true',
+                        help='Work harder to find file copies')
+    parser.add_argument('--skip-submodules', action='store_true',
+                        help='Skip processing of Git submodules')
+    parser.add_argument('--git-push-url',
+                        help='URL where to push converted Git repo')
+    parser.add_argument('git_repo_url',
+                        help='URL of Git repository to convert')
+    parser.add_argument('git_ref', help='Git ref to convert')
+    parser.add_argument('git_repo_path', help='Local path of where to store '
+                                              'Git repo clone')
+    parser.add_argument('hg_repo_path', help='Local path of where to store '
+                                             'Mercurial conversion of repo')
+
+
+    args = parser.parse_args()
+
+    if args.hg:
+        hglib.HGPATH = args.hg
+
+    configure_logging()
+
+    kwargs = get_git_linearize_kwargs(args)
+    for k in ('similarity', 'find_copies_harder', 'skip_submodules',
+              'move_to_subdir', 'git_push_url'):
+        v = getattr(args, k)
+        if v is not None:
+            kwargs[k] = v
+
+    try:
+        linearize_git_repo_to_hg(
+            args.git_repo_url,
+            args.git_ref,
+            args.git_repo_path,
+            args.hg_repo_path,
+            **kwargs)
+    except RewriteError as e:
+        logger.error('abort: %s' % str(e))
+        sys.exit(1)
+    except subprocess.CalledProcessError:
+        sys.exit(1)

new file mode 100644
--- /dev/null
+++ b/vcssync/mozvcssync/git2hg.py
@@ -0,0 +1,204 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+from __future__ import absolute_import, unicode_literals
+
+import logging
+import os
+import subprocess
+import tempfile
+
+import hglib
+
+from .gitrewrite.linearize import (
+    linearize_git_repo,
+)
+
+
+logger = logging.getLogger(__name__)
+
+
+def linearize_git_repo_to_hg(git_source_url, ref, git_repo, hg_repo,
+                             git_push_url=None,
+                             move_to_subdir=None,
+                             find_copies_harder=False,
+                             skip_submodules=False,
+                             similarity=50,
+                             **kwargs):
+    """Linearize a Git repo to an hg repo by squashing merges.
+
+    Many Git repositories (especially those on GitHub) have an excessive
+    number of merge commits and don't practice "every commit is
+    good/bisectable." When converting these repositories to Mercurial, it is
+    often desirable to ignore the non-first-parent ancestry so the result has
+    more readable history.
+
+    This function will perform such a conversion.
+
+    The source Git repository to convert is specified by ``git_source_url``
+    and ``ref``, where ``git_source_url`` is a URL understood by ``git
+    clone`` and ``ref`` is a Git ref, like ``master``. Only converting
+    a single ref is allowed.
+
+    The source Git repository is locally cloned to the path ``git_repo``.
+    This directory will be created if necessary.
+
+    If ``git_push_url`` is specified, the local clone (including converted
+    commits) will be pushed to that URL.
+
+    The conversion works in phases:
+
+    1) Git commits are rewritten into a new ref.
+    2) ``hg convert`` converts the rewritten Git commits to Mercurial.
+
+    See the docs in ``/docs/vcssync.rst`` for reasons why.
+
+    Returns a dict describing the conversion result. The dict has the following
+    keys:
+
+    git_result
+       This is a dict from ``linearize_git_repo()`` describing its results.
+    rev_map_path
+       Filesystem path to file mapping Git commit to Mercurial commit.
+    hg_before_tip_rev
+       Numeric revision of ``tip`` Mercurial changeset before conversion. ``-1``
+       if the repo was empty.
+    hg_before_tip_node
+       SHA-1 of ``tip`` Mercurial changeset before conversion. 40 0's if the
+       repo was empty.
+    hg_after_tip_rev
+       Numeric revision of ``tip`` Mercurial changeset before conversion.
+    hg_after_tip_node
+       SHA-1 of ``tip`` Mercurial changeset after conversion.
+    """
+    # Many processes execute with cwd=/ so normalize to absolute paths.
+    git_repo = os.path.abspath(git_repo)
+    hg_repo = os.path.abspath(hg_repo)
+
+    # Create Git repo, if necessary.
+    if not os.path.exists(git_repo):
+        subprocess.check_call([b'git', b'init', b'--bare', git_repo])
+        # We don't need to set up a remote because we use an explicit refspec
+        # during fetch.
+
+    subprocess.check_call([b'git', b'fetch', b'--no-tags', git_source_url,
+                           b'heads/%s:heads/%s' % (ref, ref)],
+                          cwd=git_repo)
+
+    if git_push_url:
+        subprocess.check_call([b'git', b'push', b'--mirror', git_push_url],
+                              cwd=git_repo)
+
+    git_state = linearize_git_repo(
+        git_repo,
+        b'heads/%s' % ref,
+        source_repo=git_source_url,
+        **kwargs)
+
+    if git_push_url:
+        subprocess.check_call([b'git', b'push', b'--mirror', git_push_url],
+                              cwd=git_repo)
+
+    rev_map = os.path.join(hg_repo, b'.hg', b'shamap')
+
+    result = {
+        'git_result': git_state,
+        'rev_map_path': rev_map,
+    }
+
+    # If nothing was converted, no-op if the head is already converted
+    # according to the `hg convert` revision map.
+    if not git_state['commit_map']:
+        try:
+            with open(rev_map, 'rb') as fh:
+                for line in fh:
+                    line = line.strip()
+                    if not line:
+                        continue
+                    shas = line.split()
+                    if shas[0] == git_state['dest_commit']:
+                        logger.warn('all Git commits have already been '
+                                    'converted; not doing anything')
+                        return result
+        except IOError:
+            # Fall through to doing the conversion. If it's a file permissions
+            # error, `hg convert` will abort.
+            pass
+
+    logger.warn('converting %d Git commits' % len(git_state['commit_map']))
+
+    hg_config = [
+        b'extensions.convert=',
+        # Make the rename detection limit essentially infinite.
+        b'convert.git.renamelimit=1000000000',
+        # The ``convert_revision`` that would be stored reflects the rewritten
+        # Git commit. This is valuable as a persistent SHA map, but that's it.
+        # We (hopefully) insert the original Git commit via
+        # ``source_revision_key``, so this is of marginal value.
+        b'convert.git.saverev=false',
+        b'convert.git.similarity=%d' % similarity,
+    ]
+
+    if find_copies_harder:
+        hg_config.append(b'convert.git.findcopiesharder=true')
+    if skip_submodules:
+        hg_config.append(b'convert.git.skipsubmodules=true')
+
+    if not os.path.exists(hg_repo):
+        hglib.init(hg_repo)
+
+    with hglib.open(hg_repo) as hrepo:
+        tip = hrepo[b'tip']
+        before_hg_tip_rev = tip.rev()
+        before_hg_tip_node = tip.node()
+
+    args = [hglib.HGPATH]
+    for c in hg_config:
+        args.extend([b'--config', c])
+
+    args.extend([b'convert'])
+    args.extend([b'--rev', b'refs/convert/dest/heads/%s' % ref])
+
+    # `hg convert` needs a filemap to prune empty changesets. So use an
+    # empty file even if we don't have any filemap rules.
+    with tempfile.NamedTemporaryFile('wb') as tf:
+        if move_to_subdir:
+            tf.write(b'rename . %s\n' % move_to_subdir)
+
+        tf.flush()
+
+        args.extend([b'--filemap', tf.name])
+
+        args.extend([git_repo, hg_repo, rev_map])
+
+        # hglib doesn't appear to stream output very well. So just invoke
+        # `hg` directly.
+        env = dict(os.environ)
+        env[b'HGPLAIN'] = b'1'
+        env[b'HGENCODING'] = b'utf-8'
+
+        subprocess.check_call(args, cwd='/', env=env)
+
+    with hglib.open(hg_repo) as hrepo:
+        tip = hrepo[b'tip']
+        after_hg_tip_rev = tip.rev()
+        after_hg_tip_node = tip.node()
+
+    if before_hg_tip_rev == -1:
+        convert_count = after_hg_tip_rev + 1
+    else:
+        convert_count = after_hg_tip_rev - before_hg_tip_rev
+
+    result['hg_before_tip_rev'] = before_hg_tip_rev
+    result['hg_after_tip_rev'] = after_hg_tip_rev
+    result['hg_before_tip_node'] = before_hg_tip_node
+    result['hg_after_tip_node'] = after_hg_tip_node
+    result['hg_convert_count'] = convert_count
+
+    logger.warn('%d Git commits converted to Mercurial; '
+                'previous tip: %d:%s; current tip: %d:%s' % (
+        convert_count, before_hg_tip_rev, before_hg_tip_node,
+        after_hg_tip_rev, after_hg_tip_node))
+
+    return result

--- a/vcssync/setup.py
+++ b/vcssync/setup.py
@@ -12,12 +12,13 @@ setup(
         'Development Status :: 4 - Beta',
         'Intended Audience :: Developers',
         'Programming Language :: Python :: 2.7',
     ],
     packages=find_packages(),
     entry_points={
         'console_scripts': [
             'linearize-git=mozvcssync.cli:linearize_git',
+            'linearize-git-to-hg=mozvcssync.cli:linearize_git_to_hg',
         ],
     },
     install_requires=['dulwich>=0.16', 'github3.py>=0.9.6', 'Mercurial>=4.0'],
 )

--- a/vcssync/tests/helpers.sh
+++ b/vcssync/tests/helpers.sh
@@ -6,8 +6,110 @@
 
 # make git commits deterministic and environment agnostic
 export GIT_AUTHOR_NAME=test
 export GIT_AUTHOR_EMAIL=test@example.com
 export GIT_AUTHOR_DATE='Thu Jan 1 00:00:00 1970 +0000'
 export GIT_COMMITTER_NAME=test
 export GIT_COMMITTER_EMAIL=test@example.com
 export GIT_COMMITTER_DATE='Thu Jan 1 00:00:00 1970 +0000'
+
+standardgitrepo() {
+    here=`pwd`
+    git init $1
+    cd $1
+    echo 0 > foo
+    git add foo
+    git commit -m initial
+    cat > file0 << EOF
+file0 0
+file0 1
+file0 2
+file0 3
+file0 4
+file0 5
+file0 6
+file0 7
+file0 8
+file0 9
+file0 10
+EOF
+    cat > file1 << EOF
+file1 0
+file1 1
+file1 2
+file1 3
+file1 4
+file1 5
+file1 6
+file1 7
+file1 8
+file1 9
+EOF
+
+    git add file0 file1
+    git commit -m 'add file0 and file1'
+    cp file0 file0-copy0
+    git add file0-copy0
+    git commit -m 'copy file0 to file0-copy0'
+    cp file0 file0-copy1
+    cp file0 file0-copy2
+    git add file0-copy1 file0-copy2
+    git commit -m 'copy file0 to file0-copy1 and file0-copy2'
+    git mv file0 file0-moved
+    git commit -m 'move file0 to file0-moved'
+
+    # Make copy then move source so default copy detection kicks in
+    cp file0-moved file0-copied-with-move
+    git mv file0-moved file0-moved-with-copy
+    git add file0-copied-with-move
+    git commit -m 'copy file0-moved and rename source'
+
+    # Create copies of file1 with modifications
+    cat > file1-20 << EOF
+file1 2
+file1 7
+EOF
+
+    cat > file1-50 << EOF
+file1 0
+file1 1
+file1 2
+file1 3
+file1 4
+EOF
+
+   cat > file1-80 << EOF
+file1 0
+file1 1
+file1 2
+file1 3
+file1 5
+file1 6
+file1 7
+file1 9
+EOF
+
+    git add file1-20 file1-50 file1-80
+    git commit -m 'create file1-20, file1-50 and file1-80 as copies with mods'
+
+    git branch head2
+    echo 1 > foo
+    git add foo
+    git commit -m 'dummy commit 1 on master'
+    echo 2 > foo
+    git add foo
+    git commit -m 'dummy commit 2 on master'
+    git checkout head2
+    echo 3 > bar
+    git add bar
+    git commit -m 'dummy commit 1 on head2'
+    echo 4 > bar
+    git add bar
+    git commit -m 'dummy commit 2 on head2'
+    git checkout master
+    git merge head2
+    echo 5 > foo
+    git add foo
+    git commit -m 'dummy commit 1 after merge'
+
+    cd $here
+}

new file mode 100644
--- /dev/null
+++ b/vcssync/tests/test-linearize-git-to-hg-arg-errors.t
@@ -0,0 +1,21 @@
+  $ . $TESTDIR/vcssync/tests/helpers.sh
+  $ standardgitrepo grepo > /dev/null 2>&1
+
+Git source URL does not exist
+
+  $ linearize-git-to-hg file://$TESTTMP/does/not/exist master dummy dummy
+  Initialized empty Git repository in $TESTTMP/dummy/
+  fatal: '$TESTTMP/does/not/exist' does not appear to be a git repository
+  fatal: Could not read from remote repository.
+  
+  Please make sure you have the correct access rights
+  and the repository exists.
+  [1]
+
+Source ref does not exist
+
+  $ linearize-git-to-hg file://$TESTTMP/grepo badref grepo-clone dummy
+  Initialized empty Git repository in $TESTTMP/grepo-clone/
+  fatal: Couldn't find remote ref heads/badref
+  fatal: The remote end hung up unexpectedly
+  [1]

new file mode 100644
--- /dev/null
+++ b/vcssync/tests/test-linearize-git-to-hg-basic.t
@@ -0,0 +1,62 @@
+  $ . $TESTDIR/vcssync/tests/helpers.sh
+
+  $ standardgitrepo grepo > /dev/null 2>&1
+
+  $ git --git-dir grepo/.git log --graph --format=oneline
+  * a447b9b0ff25bf17daab1c7edae4a998eca0adac dummy commit 1 after merge
+  *   fc30a4fbd1fe16d4c84ca50119e0c404c13967a3 Merge branch 'head2'
+  |\  
+  | * 7b4eab003357aaa2873a1976cb86f5c4a70f5f22 dummy commit 2 on head2
+  | * 8b358b77dede1a070e1047874be3679a31a210c9 dummy commit 1 on head2
+  * | 7a13658c4512ce4c99800417db933f4a1d3fdcb3 dummy commit 2 on master
+  * | 85fd94699e69ce4d2d55171078541c1019f111e4 dummy commit 1 on master
+  |/  
+  * ecba8e9490aa2f14345a2da0da62631928ff2968 create file1-20, file1-50 and file1-80 as copies with mods
+  * 2b77427ac0fe55e172d4174530c9bcc4b2544ff6 copy file0-moved and rename source
+  * 9fea386651d90b505d5d1fa2e70c465562b04c7d move file0 to file0-moved
+  * 4d2fb4a1b4defb3cdf7abb52d9d3c91245d26194 copy file0 to file0-copy1 and file0-copy2
+  * 73617395f86af21dde35a52e6149c8e1aac4e68f copy file0 to file0-copy0
+  * 6044be85e82c72f9115362f88c42ce94016e8718 add file0 and file1
+  * dbd62b82aaf0a7a05665d9455a9b4d490d52ddaf initial
+
+Basic git to hg linearize works
+
+  $ linearize-git-to-hg file://$TESTTMP/grepo master grepo-source grepo-dest
+  Initialized empty Git repository in $TESTTMP/grepo-source/
+  From file://$TESTTMP/grepo
+   * [new branch]      master     -> master
+  linearizing 11 commits from heads/master (dbd62b82aaf0a7a05665d9455a9b4d490d52ddaf to a447b9b0ff25bf17daab1c7edae4a998eca0adac)
+  1/11 dbd62b82aaf0a7a05665d9455a9b4d490d52ddaf initial
+  2/11 6044be85e82c72f9115362f88c42ce94016e8718 add file0 and file1
+  3/11 73617395f86af21dde35a52e6149c8e1aac4e68f copy file0 to file0-copy0
+  4/11 4d2fb4a1b4defb3cdf7abb52d9d3c91245d26194 copy file0 to file0-copy1 and file0-copy2
+  5/11 9fea386651d90b505d5d1fa2e70c465562b04c7d move file0 to file0-moved
+  6/11 2b77427ac0fe55e172d4174530c9bcc4b2544ff6 copy file0-moved and rename source
+  7/11 ecba8e9490aa2f14345a2da0da62631928ff2968 create file1-20, file1-50 and file1-80 as copies with mods
+  8/11 85fd94699e69ce4d2d55171078541c1019f111e4 dummy commit 1 on master
+  9/11 7a13658c4512ce4c99800417db933f4a1d3fdcb3 dummy commit 2 on master
+  10/11 fc30a4fbd1fe16d4c84ca50119e0c404c13967a3 Merge branch 'head2'
+  11/11 a447b9b0ff25bf17daab1c7edae4a998eca0adac dummy commit 1 after merge
+  heads/master converted; original: a447b9b0ff25bf17daab1c7edae4a998eca0adac; rewritten: aea30981234cf6848489e0ccf541fbf902b27aca
+  converting 11 Git commits
+  scanning source...
+  sorting...
+  converting...
+  10 initial
+  9 add file0 and file1
+  8 copy file0 to file0-copy0
+  7 copy file0 to file0-copy1 and file0-copy2
+  6 move file0 to file0-moved
+  5 copy file0-moved and rename source
+  4 create file1-20, file1-50 and file1-80 as copies with mods
+  3 dummy commit 1 on master
+  2 dummy commit 2 on master
+  1 Merge branch 'head2'
+  0 dummy commit 1 after merge
+  11 Git commits converted to Mercurial; previous tip: -1:0000000000000000000000000000000000000000; current tip: 10:74b93af557b18fa56b0e9fad513ef9da1a1d950f
+
+Subsequent invocation no-ops
+
+  $ linearize-git-to-hg file://$TESTTMP/grepo master grepo-source grepo-dest
+  no new commits to linearize; not doing anything
+  all Git commits have already been converted; not doing anything

new file mode 100644
--- /dev/null
+++ b/vcssync/tests/test-linearize-git-to-hg-copy-metadata.t
@@ -0,0 +1,214 @@
+  $ . $TESTDIR/vcssync/tests/helpers.sh
+
+  $ cat >> $HGRCPATH << EOF
+  > [diff]
+  > git = true
+  > EOF
+
+  $ standardgitrepo grepo > /dev/null 2>&1
+
+  $ linearize-git-to-hg file://$TESTTMP/grepo master grepo-source grepo-dest-default
+  Initialized empty Git repository in $TESTTMP/grepo-source/
+  From file://$TESTTMP/grepo
+   * [new branch]      master     -> master
+  linearizing 11 commits from heads/master (dbd62b82aaf0a7a05665d9455a9b4d490d52ddaf to a447b9b0ff25bf17daab1c7edae4a998eca0adac)
+  1/11 dbd62b82aaf0a7a05665d9455a9b4d490d52ddaf initial
+  2/11 6044be85e82c72f9115362f88c42ce94016e8718 add file0 and file1
+  3/11 73617395f86af21dde35a52e6149c8e1aac4e68f copy file0 to file0-copy0
+  4/11 4d2fb4a1b4defb3cdf7abb52d9d3c91245d26194 copy file0 to file0-copy1 and file0-copy2
+  5/11 9fea386651d90b505d5d1fa2e70c465562b04c7d move file0 to file0-moved
+  6/11 2b77427ac0fe55e172d4174530c9bcc4b2544ff6 copy file0-moved and rename source
+  7/11 ecba8e9490aa2f14345a2da0da62631928ff2968 create file1-20, file1-50 and file1-80 as copies with mods
+  8/11 85fd94699e69ce4d2d55171078541c1019f111e4 dummy commit 1 on master
+  9/11 7a13658c4512ce4c99800417db933f4a1d3fdcb3 dummy commit 2 on master
+  10/11 fc30a4fbd1fe16d4c84ca50119e0c404c13967a3 Merge branch 'head2'
+  11/11 a447b9b0ff25bf17daab1c7edae4a998eca0adac dummy commit 1 after merge
+  heads/master converted; original: a447b9b0ff25bf17daab1c7edae4a998eca0adac; rewritten: aea30981234cf6848489e0ccf541fbf902b27aca
+  converting 11 Git commits
+  scanning source...
+  sorting...
+  converting...
+  10 initial
+  9 add file0 and file1
+  8 copy file0 to file0-copy0
+  7 copy file0 to file0-copy1 and file0-copy2
+  6 move file0 to file0-moved
+  5 copy file0-moved and rename source
+  4 create file1-20, file1-50 and file1-80 as copies with mods
+  3 dummy commit 1 on master
+  2 dummy commit 2 on master
+  1 Merge branch 'head2'
+  0 dummy commit 1 after merge
+  11 Git commits converted to Mercurial; previous tip: -1:0000000000000000000000000000000000000000; current tip: 10:74b93af557b18fa56b0e9fad513ef9da1a1d950f
+
+Move annotation should be preserved automatically
+
+  $ hg -R grepo-dest-default export 4
+  # HG changeset patch
+  # User test <test@example.com>
+  # Date 0 0
+  #      Thu Jan 01 00:00:00 1970 +0000
+  # Node ID 045473c2b7065422c50de2de883bbfabd42307e9
+  # Parent  4670490276d96d9f5aafbcfba095b94401ce2f7b
+  move file0 to file0-moved
+  
+  diff --git a/file0 b/file0-moved
+  rename from file0
+  rename to file0-moved
+
+Copy annotation should be preserved automatically
+
+  $ hg -R grepo-dest-default export 5
+  # HG changeset patch
+  # User test <test@example.com>
+  # Date 0 0
+  #      Thu Jan 01 00:00:00 1970 +0000
+  # Node ID 2f1c561c2bba03de041ae91b9bd996a8e1592a46
+  # Parent  045473c2b7065422c50de2de883bbfabd42307e9
+  copy file0-moved and rename source
+  
+  diff --git a/file0-moved b/file0-copied-with-move
+  rename from file0-moved
+  rename to file0-copied-with-move
+  diff --git a/file0-moved b/file0-moved-with-copy
+  copy from file0-moved
+  copy to file0-moved-with-copy
+
+Normal copy won't be detected if source not modified
+
+  $ hg -R grepo-dest-default export 2
+  # HG changeset patch
+  # User test <test@example.com>
+  # Date 0 0
+  #      Thu Jan 01 00:00:00 1970 +0000
+  # Node ID ef5cf78e1c5224adea8f6cebba99ed88bed64389
+  # Parent  9b56156dddc3d86f3afaba790ad91260c85c74b2
+  copy file0 to file0-copy0
+  
+  diff --git a/file0-copy0 b/file0-copy0
+  new file mode 100644
+  --- /dev/null
+  +++ b/file0-copy0
+  @@ -0,0 +1,11 @@
+  +file0 0
+  +file0 1
+  +file0 2
+  +file0 3
+  +file0 4
+  +file0 5
+  +file0 6
+  +file0 7
+  +file0 8
+  +file0 9
+  +file0 10
+
+--find-copies-harder will find copies
+
+  $ linearize-git-to-hg --find-copies-harder file://$TESTTMP/grepo master grepo-source grepo-dest-find-copy-harder > /dev/null 2>&1
+
+  $ hg -R grepo-dest-find-copy-harder export 2
+  # HG changeset patch
+  # User test <test@example.com>
+  # Date 0 0
+  #      Thu Jan 01 00:00:00 1970 +0000
+  # Node ID 69b9ae19ba84e5c77b119294715e992a8d7070bf
+  # Parent  9b56156dddc3d86f3afaba790ad91260c85c74b2
+  copy file0 to file0-copy0
+  
+  diff --git a/file0 b/file0-copy0
+  copy from file0
+  copy to file0-copy0
+
+Copy detection similarity is sane
+
+  $ hg -R grepo-dest-find-copy-harder export 6
+  # HG changeset patch
+  # User test <test@example.com>
+  # Date 0 0
+  #      Thu Jan 01 00:00:00 1970 +0000
+  # Node ID b5b3e192ecdecbfc25d1ef6241664db3c63ef4d0
+  # Parent  c1afa6c62b584e017c1a3900055d2eba740092b5
+  create file1-20, file1-50 and file1-80 as copies with mods
+  
+  diff --git a/file1-20 b/file1-20
+  new file mode 100644
+  --- /dev/null
+  +++ b/file1-20
+  @@ -0,0 +1,2 @@
+  +file1 2
+  +file1 7
+  diff --git a/file1 b/file1-50
+  copy from file1
+  copy to file1-50
+  --- a/file1
+  +++ b/file1-50
+  @@ -3,8 +3,3 @@
+   file1 2
+   file1 3
+   file1 4
+  -file1 5
+  -file1 6
+  -file1 7
+  -file1 8
+  -file1 9
+  diff --git a/file1 b/file1-80
+  copy from file1
+  copy to file1-80
+  --- a/file1
+  +++ b/file1-80
+  @@ -2,9 +2,7 @@
+   file1 1
+   file1 2
+   file1 3
+  -file1 4
+   file1 5
+   file1 6
+   file1 7
+  -file1 8
+   file1 9
+
+Increase similarity threshold removes copy annotation from file1-50
+
+  $ linearize-git-to-hg --copy-similarity 70 --find-copies-harder file://$TESTTMP/grepo master grepo-source grepo-dest-similarity-70 > /dev/null 2>&1
+
+  $ hg -R grepo-dest-similarity-70 export 6
+  # HG changeset patch
+  # User test <test@example.com>
+  # Date 0 0
+  #      Thu Jan 01 00:00:00 1970 +0000
+  # Node ID 2cbb8f45b28f77c4b45382629a4b9fa297df0960
+  # Parent  c1afa6c62b584e017c1a3900055d2eba740092b5
+  create file1-20, file1-50 and file1-80 as copies with mods
+  
+  diff --git a/file1-20 b/file1-20
+  new file mode 100644
+  --- /dev/null
+  +++ b/file1-20
+  @@ -0,0 +1,2 @@
+  +file1 2
+  +file1 7
+  diff --git a/file1-50 b/file1-50
+  new file mode 100644
+  --- /dev/null
+  +++ b/file1-50
+  @@ -0,0 +1,5 @@
+  +file1 0
+  +file1 1
+  +file1 2
+  +file1 3
+  +file1 4
+  diff --git a/file1 b/file1-80
+  copy from file1
+  copy to file1-80
+  --- a/file1
+  +++ b/file1-80
+  @@ -2,9 +2,7 @@
+   file1 1
+   file1 2
+   file1 3
+  -file1 4
+   file1 5
+   file1 6
+   file1 7
+  -file1 8
+   file1 9

new file mode 100644
--- /dev/null
+++ b/vcssync/tests/test-linearize-git-to-hg-move-to-subdir.t
@@ -0,0 +1,36 @@
+  $ . $TESTDIR/vcssync/tests/helpers.sh
+  $ standardgitrepo grepo > /dev/null 2>&1
+
+--move-to-subdir will move files in git repo to subdirectory in hg
+
+  $ linearize-git-to-hg --move-to-subdir subdir file://$TESTTMP/grepo master grepo-source grepo-dest-0 > /dev/null 2>&1
+
+  $ hg --cwd grepo-dest-0 files -r tip
+  subdir/bar
+  subdir/file0-copied-with-move
+  subdir/file0-copy0
+  subdir/file0-copy1
+  subdir/file0-copy2
+  subdir/file0-moved-with-copy
+  subdir/file1
+  subdir/file1-20
+  subdir/file1-50
+  subdir/file1-80
+  subdir/foo
+
+Multiple child directories works
+
+  $ linearize-git-to-hg --move-to-subdir dir0/dir1/dir2 file://$TESTTMP/grepo master grepo-source grepo-dest-1 > /dev/null 2>&1
+
+  $ hg --cwd grepo-dest-1 files -r tip
+  dir0/dir1/dir2/bar
+  dir0/dir1/dir2/file0-copied-with-move
+  dir0/dir1/dir2/file0-copy0
+  dir0/dir1/dir2/file0-copy1
+  dir0/dir1/dir2/file0-copy2
+  dir0/dir1/dir2/file0-moved-with-copy
+  dir0/dir1/dir2/file1
+  dir0/dir1/dir2/file1-20
+  dir0/dir1/dir2/file1-50
+  dir0/dir1/dir2/file1-80
+  dir0/dir1/dir2/foo

new file mode 100644
--- /dev/null
+++ b/vcssync/tests/test-linearize-git-to-hg-push-git.t
@@ -0,0 +1,98 @@
+  $ . $TESTDIR/vcssync/tests/helpers.sh
+
+  $ standardgitrepo grepo > /dev/null 2>&1
+
+  $ git init --bare grepo-mirror
+  Initialized empty Git repository in $TESTTMP/grepo-mirror/
+
+--git-push-url will mirror the local Git repo to a remote after changes
+
+  $ linearize-git-to-hg --git-push-url file://$TESTTMP/grepo-mirror file://$TESTTMP/grepo master grepo-source hgrepo-dest
+  Initialized empty Git repository in $TESTTMP/grepo-source/
+  From file://$TESTTMP/grepo
+   * [new branch]      master     -> master
+  To file://$TESTTMP/grepo-mirror
+   * [new branch]      master -> master
+  linearizing 11 commits from heads/master (dbd62b82aaf0a7a05665d9455a9b4d490d52ddaf to a447b9b0ff25bf17daab1c7edae4a998eca0adac)
+  1/11 dbd62b82aaf0a7a05665d9455a9b4d490d52ddaf initial
+  2/11 6044be85e82c72f9115362f88c42ce94016e8718 add file0 and file1
+  3/11 73617395f86af21dde35a52e6149c8e1aac4e68f copy file0 to file0-copy0
+  4/11 4d2fb4a1b4defb3cdf7abb52d9d3c91245d26194 copy file0 to file0-copy1 and file0-copy2
+  5/11 9fea386651d90b505d5d1fa2e70c465562b04c7d move file0 to file0-moved
+  6/11 2b77427ac0fe55e172d4174530c9bcc4b2544ff6 copy file0-moved and rename source
+  7/11 ecba8e9490aa2f14345a2da0da62631928ff2968 create file1-20, file1-50 and file1-80 as copies with mods
+  8/11 85fd94699e69ce4d2d55171078541c1019f111e4 dummy commit 1 on master
+  9/11 7a13658c4512ce4c99800417db933f4a1d3fdcb3 dummy commit 2 on master
+  10/11 fc30a4fbd1fe16d4c84ca50119e0c404c13967a3 Merge branch 'head2'
+  11/11 a447b9b0ff25bf17daab1c7edae4a998eca0adac dummy commit 1 after merge
+  heads/master converted; original: a447b9b0ff25bf17daab1c7edae4a998eca0adac; rewritten: aea30981234cf6848489e0ccf541fbf902b27aca
+  To file://$TESTTMP/grepo-mirror
+   * [new branch]      refs/convert/dest/heads/master -> refs/convert/dest/heads/master
+   * [new branch]      refs/convert/source/heads/master -> refs/convert/source/heads/master
+  converting 11 Git commits
+  scanning source...
+  sorting...
+  converting...
+  10 initial
+  9 add file0 and file1
+  8 copy file0 to file0-copy0
+  7 copy file0 to file0-copy1 and file0-copy2
+  6 move file0 to file0-moved
+  5 copy file0-moved and rename source
+  4 create file1-20, file1-50 and file1-80 as copies with mods
+  3 dummy commit 1 on master
+  2 dummy commit 2 on master
+  1 Merge branch 'head2'
+  0 dummy commit 1 after merge
+  11 Git commits converted to Mercurial; previous tip: -1:0000000000000000000000000000000000000000; current tip: 10:74b93af557b18fa56b0e9fad513ef9da1a1d950f
+
+All refs from local Git repo should be in mirror
+
+  $ git -C grepo-source for-each-ref
+  aea30981234cf6848489e0ccf541fbf902b27aca commit	refs/convert/dest/heads/master
+  a447b9b0ff25bf17daab1c7edae4a998eca0adac commit	refs/convert/source/heads/master
+  a447b9b0ff25bf17daab1c7edae4a998eca0adac commit	refs/heads/master
+
+  $ git -C grepo-mirror for-each-ref
+  aea30981234cf6848489e0ccf541fbf902b27aca commit	refs/convert/dest/heads/master
+  a447b9b0ff25bf17daab1c7edae4a998eca0adac commit	refs/convert/source/heads/master
+  a447b9b0ff25bf17daab1c7edae4a998eca0adac commit	refs/heads/master
+
+Incremental conversion will keep Git repo in sync
+
+  $ cd grepo
+  $ touch incremental
+  $ git add incremental
+  $ git commit -m 'add incremental'
+  [master 4040c16] add incremental
+   1 file changed, 0 insertions(+), 0 deletions(-)
+   create mode 100644 incremental
+  $ cd ..
+
+  $ linearize-git-to-hg --git-push-url file://$TESTTMP/grepo-mirror file://$TESTTMP/grepo master grepo-source hgrepo-dest
+  From file://$TESTTMP/grepo
+     a447b9b..4040c16  master     -> master
+  To file://$TESTTMP/grepo-mirror
+     a447b9b..4040c16  master -> master
+  linearizing 1 commits from heads/master (4040c1631489c25dd4e0fd1606c4a065e1a24194 to 4040c1631489c25dd4e0fd1606c4a065e1a24194)
+  1/1 4040c1631489c25dd4e0fd1606c4a065e1a24194 add incremental
+  heads/master converted; original: 4040c1631489c25dd4e0fd1606c4a065e1a24194; rewritten: d6ec61184bff36a58159341c2584f3cda9dd0b58
+  To file://$TESTTMP/grepo-mirror
+     aea3098..d6ec611  refs/convert/dest/heads/master -> refs/convert/dest/heads/master
+     a447b9b..4040c16  refs/convert/source/heads/master -> refs/convert/source/heads/master
+  converting 1 Git commits
+  scanning source...
+  sorting...
+  converting...
+  0 add incremental
+  1 Git commits converted to Mercurial; previous tip: 10:74b93af557b18fa56b0e9fad513ef9da1a1d950f; current tip: 11:b53d6fba975e3face586964aace142716b2191a7
+
+  $ git -C grepo-source for-each-ref
+  d6ec61184bff36a58159341c2584f3cda9dd0b58 commit	refs/convert/dest/heads/master
+  4040c1631489c25dd4e0fd1606c4a065e1a24194 commit	refs/convert/source/heads/master
+  4040c1631489c25dd4e0fd1606c4a065e1a24194 commit	refs/heads/master
+
+  $ git -C grepo-mirror for-each-ref
+  d6ec61184bff36a58159341c2584f3cda9dd0b58 commit	refs/convert/dest/heads/master
+  4040c1631489c25dd4e0fd1606c4a065e1a24194 commit	refs/convert/source/heads/master
+  4040c1631489c25dd4e0fd1606c4a065e1a24194 commit	refs/heads/master

new file mode 100644
--- /dev/null
+++ b/vcssync/tests/test-linearize-git-to-hg-source-annotations.t
@@ -0,0 +1,61 @@
+  $ . $TESTDIR/vcssync/tests/helpers.sh
+  $ standardgitrepo grepo > /dev/null 2>&1
+
+Note: since source repo is in $TESTTMP which is dynamic, commit SHA-1s aren't stable!
+
+  $ linearize-git-to-hg --source-repo-key Source-Repo --source-revision-key Source-Revision file://$TESTTMP/grepo master grepo-source grepo-dest
+  Initialized empty Git repository in $TESTTMP/grepo-source/
+  From file://$TESTTMP/grepo
+   * [new branch]      master     -> master
+  linearizing 11 commits from heads/master (dbd62b82aaf0a7a05665d9455a9b4d490d52ddaf to a447b9b0ff25bf17daab1c7edae4a998eca0adac)
+  1/11 dbd62b82aaf0a7a05665d9455a9b4d490d52ddaf initial
+  2/11 6044be85e82c72f9115362f88c42ce94016e8718 add file0 and file1
+  3/11 73617395f86af21dde35a52e6149c8e1aac4e68f copy file0 to file0-copy0
+  4/11 4d2fb4a1b4defb3cdf7abb52d9d3c91245d26194 copy file0 to file0-copy1 and file0-copy2
+  5/11 9fea386651d90b505d5d1fa2e70c465562b04c7d move file0 to file0-moved
+  6/11 2b77427ac0fe55e172d4174530c9bcc4b2544ff6 copy file0-moved and rename source
+  7/11 ecba8e9490aa2f14345a2da0da62631928ff2968 create file1-20, file1-50 and file1-80 as copies with mods
+  8/11 85fd94699e69ce4d2d55171078541c1019f111e4 dummy commit 1 on master
+  9/11 7a13658c4512ce4c99800417db933f4a1d3fdcb3 dummy commit 2 on master
+  10/11 fc30a4fbd1fe16d4c84ca50119e0c404c13967a3 Merge branch 'head2'
+  11/11 a447b9b0ff25bf17daab1c7edae4a998eca0adac dummy commit 1 after merge
+  heads/master converted; original: a447b9b0ff25bf17daab1c7edae4a998eca0adac; rewritten: * (glob)
+  converting 11 Git commits
+  scanning source...
+  sorting...
+  converting...
+  10 initial
+  9 add file0 and file1
+  8 copy file0 to file0-copy0
+  7 copy file0 to file0-copy1 and file0-copy2
+  6 move file0 to file0-moved
+  5 copy file0-moved and rename source
+  4 create file1-20, file1-50 and file1-80 as copies with mods
+  3 dummy commit 1 on master
+  2 dummy commit 2 on master
+  1 Merge branch 'head2'
+  0 dummy commit 1 after merge
+  11 Git commits converted to Mercurial; previous tip: -1:0000000000000000000000000000000000000000; current tip: 10:* (glob)
+
+Key: Value metadata identifying source should appear in commit message
+TODO Mercurial 4.1 will remove convert_revision from extra, which is wanted
+
+  $ hg -R grepo-dest log --debug -r 0
+  changeset:   0:* (glob)
+  phase:       draft
+  parent:      -1:0000000000000000000000000000000000000000
+  parent:      -1:0000000000000000000000000000000000000000
+  manifest:    0:cba485ca3678256e044428f70f58291196f6e9de
+  user:        test <test@example.com>
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  files+:      foo
+  extra:       branch=default
+  extra:       convert_revision=* (glob)
+  description:
+  initial
+  
+  Source-Repo: file://$TESTTMP/grepo
+  Source-Revision: dbd62b82aaf0a7a05665d9455a9b4d490d52ddaf
+  
+  
+