Fix zombie files in merge

# HG changeset patch
# User [e-mail]
# Node ID 57667c9b93a5a743e4629d15a0e6bd76699130c3
# Parent  d2994b5298fb20f87dc1d4747635b280db3c0526

Fix zombie files in merge

Keir Fraser observed the following:

> I made a small test case that illustrates the bug in merging changesets 
> with 'hg remove's in them:
> 
> 1. Create a repository A containing files foo & bar.
> 2. Create clone called B.
> 3. A removes file bar, and commits this removal.
> 4. B edits file foo, and commits this edit.
> 
> Now, if B:
>   # hg pull ../A; hg update -m; hg commit
> Then bar remains deleted.
> 
> If A:
>   # hg pull ../B; hg update -m; hg commit
> Then bar is resurrected!
> 
> It looks as though, when you merge across a branch, any deletions in 
> your own branch are forgotten.
> ...
> Fixing this is a must, as zombie files are a real pain. :-)

Keir later patched our local copy of hg as shown below, which fixes
the problem.  I've also enclosed a test which captures the test Keir
outlined...

Files deleted on a branch should not automatically reappear in a merge

Patch notes:
 1. The first chunk does not change behaviour, but cleans up the code
    to more closely match check of 'force' in the second chunk. I
    think it makes the code clearer.
 2. The second chunk fixes two bugs --
    i.  If we choose to keep a remotely-changed locally-deleted file,
        then we need to 'get' that file. If we choose to delete it
        then no action need be taken (it is already deleted in the
        working manifest). Without this fix, choosing to delete would
        get a Python traceback.
    ii. The test for whether the file was remotely-created is
        insufficient. It is only true if f is not in the common
        ancestor. Otherwise the file was deleted locally, and should
        remain deleted. (this is the most important fix!)


Index: hg/tests/test-merge6
===================================================================

tests/test-merge6

@@ -0,0 +1,46 b''
+#!/bin/sh -x
+
+cat <<'EOF' > merge
+#!/bin/sh
+echo merging for `basename $1`
+EOF
+chmod +x merge
+export HGMERGE=./merge
+
+mkdir A1
+cd A1
+hg init
+echo This is file foo1 > foo
+echo This is file bar1 > bar
+hg add foo bar
+hg commit -t "commit text" -d "0 0" -u user
+
+cd ..
+hg clone A1 B1
+
+cd A1
+rm bar
+hg remove bar
+hg commit -t "commit test" -d "0 0" -u user
+
+cd ../B1
+echo This is file foo22 > foo
+hg commit -t "commit test" -d "0 0" -u user
+
+cd ..
+hg clone A1 A2
+hg clone B1 B2
+
+cd A1
+hg pull ../B1
+hg update -m
+hg commit -t "commit test" -d "0 0" -u user
+echo bar should remain deleted.
+hg manifest
+
+cd ../B2
+hg pull ../A2
+hg update -m
+hg commit -t "commit test" -d "0 0" -u user
+echo bar should remain deleted.
+hg manifest

tests/test-merge6.out

@@ -0,0 +1,53 b''
++ cat
++ chmod +x merge
++ export HGMERGE=./merge
++ HGMERGE=./merge
++ mkdir A1
++ cd A1
++ hg init
++ echo This is file foo1
++ echo This is file bar1
++ hg add foo bar
++ hg commit -t 'commit text' -d '0 0' -u user
++ cd ..
++ hg clone A1 B1
++ cd A1
++ rm bar
++ hg remove bar
++ hg commit -t 'commit test' -d '0 0' -u user
++ cd ../B1
++ echo This is file foo22
++ hg commit -t 'commit test' -d '0 0' -u user
++ cd ..
++ hg clone A1 A2
++ hg clone B1 B2
++ cd A1
++ hg pull ../B1
+pulling from ../B1
+searching for changes
+adding changesets
+adding manifests
+adding file revisions
+modified 1 files, added 1 changesets and 1 new revisions
+(run 'hg update' to get a working copy)
++ hg update -m
++ hg commit -t 'commit test' -d '0 0' -u user
++ echo bar should remain deleted.
+bar should remain deleted.
++ hg manifest
+6b70e9e451a5a33faad7bbebe627e46b937b7364 644 foo
++ cd ../B2
++ hg pull ../A2
+pulling from ../A2
+searching for changes
+adding changesets
+adding manifests
+adding file revisions
+modified 0 files, added 1 changesets and 0 new revisions
+(run 'hg update' to get a working copy)
++ hg update -m
++ hg commit -t 'commit test' -d '0 0' -u user
++ echo bar should remain deleted.
+bar should remain deleted.
++ hg manifest
+6b70e9e451a5a33faad7bbebe627e46b937b7364 644 foo

mercurial/hg.py

@@ -1179,9 +1179,9 b' class localrepository:'
                             mark[f] = 1
                 del m2[f]
             elif f in ma:
-                if not force and n != ma[f]:
-                    r = ""
-                    if linear_path or allow:
+                if n != ma[f]:
+                    r = "d"
+                    if not force and (linear_path or allow):
                         r = self.ui.prompt(
                             (" local changed %s which remote deleted\n" % f) +
                             "(k)eep or (d)elete?", "[kd]", "k")
@@ -1203,16 +1203,18 b' class localrepository:'
         for f, n in m2.iteritems():
             if choose and not choose(f): continue
             if f[0] == "/": continue
-            if not force and f in ma and n != ma[f]:
-                r = ""
-                if linear_path or allow:
+            if f in ma and n != ma[f]:
+                r = "k"
+                if not force and (linear_path or allow):
                     r = self.ui.prompt(
                         ("remote changed %s which local deleted\n" % f) +
                         "(k)eep or (d)elete?", "[kd]", "k")
-                if r == "d": remove.append(f)
-            else:
+                if r == "k": get[f] = n
+            elif f not in ma:
                 self.ui.debug("remote created %s\n" % f)
                 get[f] = n
+            else:
+                self.ui.debug("local deleted %s\n" % f)
 
         del mw, m1, m2, ma
 

tests/test-merge5.out

@@ -13,6 +13,7 b''
 + yes k
 + hg update 1
 this update spans a branch affecting the following files:
+ b
 aborting update spanning branches!
 (use update -m to perform a branch merge)
 + exit 0