[PATCH] commit: abort on merge with missing files

[Patrick Mezard]

# HG changeset patch
# User Patrick Mezard <patrick at mezard.eu>
# Date 1335618117 -7200
# Branch stable
# Node ID 63c817ea4a70a977a212cb01c8ec13a7e1ee59a2
# Parent  39d1f83eb05d424fc467d2e0eece8c4a8cefd35a
commit: abort on merge with missing files

Here is a script illustrating the previous behaviour:

The merge brings a new file 'b' from remote
  $ hg merge 1 --debug
    searching for copies back to rev 1
    unmatched files in other:
     b
  resolving manifests
   overwrite: False, partial: False
   ancestor: 07f494440405, local: 540395c44225+, remote: 102a90ea7b4a
   b: remote created -> g
  updating: b 1/1 files (100.00%)
  getting b
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

Delete but do not remove b
  $ rm b
  $ hg st
  ! b

The commit succeeds
  $ hg commit -m merge
  $ hg parents --template "{rev} {desc|firstline} files: {files}\n"
  3 merge files:
  $ hg st
  ! b

b changes were ignored, but even b existence was ignored
  $ hg manifest
  a

This happens because localrepo.commitctx() checks the input ctx.files(), which
is empty for workingctx.files() only returns added, modified or removed
entries, and bypass files/manifest updates completely. So the committed
revision manifest is the same as its first parent one, not containing the 'b'
file.

This patch forces the commit to abort in presence of a merge and missing files.
test-merge4.t is modified accordingly as it was introduced to check hg was not
just terminating with a traceback (5e9e8b8d2629).

diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -1147,6 +1147,9 @@
                 and wctx.branch() == wctx.p1().branch()):
                 return None
 
+            if merge and changes[3]:
+                raise util.Abort(_("cannot commit merge with missing files"))
+
             ms = mergemod.mergestate(self)
             for f in changes[0]:
                 if f in ms and ms[f] == 'u':
diff --git a/tests/test-merge4.t b/tests/test-merge4.t
--- a/tests/test-merge4.t
+++ b/tests/test-merge4.t
@@ -16,5 +16,10 @@
   (branch merge, don't forget to commit)
   $ rm b
   $ echo This is file c22 > c
+
+Test hg behaves when committing with a missing file added by a merge
+
   $ hg commit -m "commit #3"
+  abort: cannot commit merge with missing files
+  [255]