amend: do not drop missing files (issue5732)

samefile() can be wrong since wctx.manifest() does not include missing files,
whereas missing files should be preserved on commit.

mercurial/cmdutil.py

@@ -3166,9 +3166,11 b' def amend(ui, repo, old, extra, pats, op'
             # introduced file X and the file was renamed in the working
             # copy, then those two files are the same and
             # we can discard X from our list of files. Likewise if X
-            # was deleted, it's no longer relevant
+            # was removed, it's no longer relevant. If X is missing (aka
+            # deleted), old X must be preserved.
             files.update(filestoamend)
-            files = [f for f in files if not samefile(f, wctx, base)]
+            files = [f for f in files if (not samefile(f, wctx, base)
+                                          or f in wctx.deleted())]
 
             def filectxfn(repo, ctx_, path):
                 try:

tests/test-amend.t

@@ -268,8 +268,6 b' amend r1 to include wc changes'
 
 clean/modified/removed/added states of the amended revision
 
-BROKEN: missing files are removed
-
   $ hg status --all --change . 'glob:content1_*_content1-tracked'
   C content1_content1_content1-tracked
   C content1_content2_content1-tracked
@@ -297,7 +295,7 b' BROKEN: missing files are removed'
   $ hg status --all --change . 'glob:missing_content2_*'
   A missing_content2_content2-tracked
   A missing_content2_content3-tracked
-  A missing_content2_missing-tracked (false !)
+  A missing_content2_missing-tracked
   $ hg status --all --change . 'glob:missing_missing_*'
   A missing_missing_content3-tracked