Patchwork D10115: copies: choose target directory based on longest match

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Submitter phabricator
Date March 5, 2021, 12:25 a.m.
Message ID <differential-rev-PHID-DREV-7oedgiegd4aoel7fcrrn-req@mercurial-scm.org>
Download mbox | patch
Permalink /patch/48430/
State Superseded
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phabricator - March 5, 2021, 12:25 a.m.
martinvonz created this revision.
Herald added a reviewer: hg-reviewers.
Herald added a subscriber: mercurial-patches.

REVISION SUMMARY
  If one side of a merge renames `dir1/` to `dir2/` and the subdirectory
  `dir1/subdir1/` to `dir2/subdir2/`, and the other side of the merge
  adds a file in `dir1/subdir1/`, we should clearly move that into
  `dir2/subdir2/`. We already detect the directories correctly before
  this patch, but we iterate over them in arbitrary order. That results
  in the new file sometimes ending up in `dir2/subdir1/` instead. This
  patch fixes it by iterating over the source directories by visiting
  subdirectories first. That's achieved by simply iterating over them in
  reverse lexicographical order.
  
  Without the fix, the test case still passes on Python 2 but fails on
  Python 3. It depends on the iteration order of the dict. I did not
  look into how it's built up and why it behaved differently before the
  fix. I could probably have gotten it to fail on Python 2 as well by
  choosing different directory names.

REPOSITORY
  rHG Mercurial

BRANCH
  default

REVISION DETAIL
  https://phab.mercurial-scm.org/D10115

AFFECTED FILES
  mercurial/copies.py
  tests/test-rename-dir-merge.t

CHANGE DETAILS




To: martinvonz, #hg-reviewers
Cc: mercurial-patches, mercurial-devel

Patch

diff --git a/tests/test-rename-dir-merge.t b/tests/test-rename-dir-merge.t
--- a/tests/test-rename-dir-merge.t
+++ b/tests/test-rename-dir-merge.t
@@ -294,3 +294,45 @@ 
   M t/t
   R a/s
   R a/t
+
+  $ cd ..
+
+
+Test that files are moved to a new directory based on the path prefix that
+matches the most. dir1/ below gets renamed to dir2/, and dir1/subdir1/ gets
+renamed to dir2/subdir2/. We want dir1/subdir1/newfile to move to
+dir2/subdir2/ (not to dir2/subdir1/ as we would infer based on just the rename
+of dir1/ to dir2/).
+
+  $ hg init nested-renames
+  $ cd nested-renames
+  $ mkdir dir1
+  $ echo a > dir1/file1
+  $ echo b > dir1/file2
+  $ mkdir dir1/subdir1
+  $ echo c > dir1/subdir1/file3
+  $ echo d > dir1/subdir1/file4
+  $ hg ci -Aqm initial
+  $ hg mv dir1 dir2
+  moving dir1/file1 to dir2/file1
+  moving dir1/file2 to dir2/file2
+  moving dir1/subdir1/file3 to dir2/subdir1/file3
+  moving dir1/subdir1/file4 to dir2/subdir1/file4
+  $ hg mv dir2/subdir1 dir2/subdir2
+  moving dir2/subdir1/file3 to dir2/subdir2/file3
+  moving dir2/subdir1/file4 to dir2/subdir2/file4
+  $ hg ci -m 'move dir1/ to dir2/ and dir1/subdir1/ to dir2/subdir2/'
+  $ hg co 0
+  4 files updated, 0 files merged, 4 files removed, 0 files unresolved
+  $ echo e > dir1/subdir1/file5
+  $ hg ci -Aqm 'add file in dir1/subdir1/'
+  $ hg merge 1
+  5 files updated, 0 files merged, 4 files removed, 0 files unresolved
+  (branch merge, don't forget to commit)
+  $ hg files
+  dir2/file1
+  dir2/file2
+  dir2/subdir2/file3
+  dir2/subdir2/file4
+  dir2/subdir2/file5
+  $ cd ..
diff --git a/mercurial/copies.py b/mercurial/copies.py
--- a/mercurial/copies.py
+++ b/mercurial/copies.py
@@ -1096,11 +1096,17 @@ 
             b"   discovered dir src: '%s' -> dst: '%s'\n" % (d, dirmove[d])
         )
 
+    # Sort the directories in reverse order, so we find children first
+    # For example, if dir1/ was renamed to dir2/, and dir1/subdir1/
+    # was renamed to dir2/subdir2/, we want to move dir1/subdir1/file
+    # to dir2/subdir2/file (not dir2/subdir1/file)
+    dirmove_children_first = sorted(dirmove, reverse=True)
+
     movewithdir = {}
     # check unaccounted nonoverlapping files against directory moves
     for f in addedfilesfn():
         if f not in fullcopy:
-            for d in dirmove:
+            for d in dirmove_children_first:
                 if f.startswith(d):
                     # new file added in a directory that was moved, move it
                     df = dirmove[d] + f[len(d) :]