[PATCH 2 of 7 STABLE] merge: check collision between files and directories before updating (issue29)

[FUJIWARA Katsunori]

# HG changeset patch
# User FUJIWARA Katsunori <foozy at lares.dti.ne.jp>
# Date 1367870651 -32400
#      Tue May 07 05:04:11 2013 +0900
# Branch stable
# Node ID 1bede396d3f4dfd7763e214befd12fea9df63130
# Parent  127d7233b406699617f6dbcbc34e5ea00c2aa223
merge: check collision between files and directories before updating (issue29)

For example, it is assumed that the revision X consists file 'A', and
the revision Y consists of file 'A/A'. Merging between X and Y causes
collision between file 'A' (on X) and directory 'A' of 'A/A' (on Y).

Before this patch, such collision is detected via failure of "mkdir()"
on existing file 'A' (merging Y into X) or "unlink()" on directory 'A'
of 'A/A' (merging X into Y) while updating working directory.

This causes incomplete working directory status.

This patch checks collision between files and directories before
updating working directory.

Collision check logic is a little redundant to fix collision problem
with largefiles extension easily in succeeding patch.

This patch skips collision check only for clean updating on case
sensitive filesystem, because the files and the directories in the
merged manifest may collide each other, even on case sensitive
filesystem.

This patch also adds "no-icasefs" to "#if" directive in
test-audit-path.t, because collision between symbolic-link 'back' and
directory 'back' of 'back/test' is detected before check by
pathauditor on case insensitive filesystem, and this changes detail
of abort message.

diff --git a/mercurial/merge.py b/mercurial/merge.py
--- a/mercurial/merge.py
+++ b/mercurial/merge.py
@@ -8,7 +8,7 @@
 from node import nullid, nullrev, hex, bin
 from i18n import _
 from mercurial import obsolete
-import error, util, filemerge, copies, subrepo, worker, dicthelpers
+import error, util, filemerge, copies, subrepo, worker, dicthelpers, scmutil
 import errno, os, shutil
 
 class mergestate(object):
@@ -138,7 +138,7 @@
 
     return actions
 
-def _checkcollision(repo, wmf, actions, prompts):
+def _checkcollision(repo, wmf, actions, prompts, casesensitive):
     # build provisional merged manifest up
     pmmf = set(wmf)
 
@@ -185,14 +185,36 @@
         assert op, m
         op(f, None)
 
-    # check case-folding collision in provisional merged manifest
-    foldmap = {}
-    for f in sorted(pmmf):
-        fold = util.normcase(f)
-        if fold in foldmap:
-            raise util.Abort(_("case-folding collision between %s and %s")
-                             % (f, foldmap[fold]))
-        foldmap[fold] = f
+    if casesensitive:
+        normcase = None
+        def check(f, nf):
+            if nf in dirs:
+                raise util.Abort(_("collision between file %s and "
+                                   "other directory") % (f))
+    else:
+        normcase = util.normcase
+        foldmap = {}
+        def check(f, nf):
+            if nf in dirs:
+                raise util.Abort(_("collision between file %s and "
+                                   "other directory") % (f))
+            if nf in foldmap:
+                raise util.Abort(_("case-folding collision between %s and %s")
+                                 % (f, foldmap[nf]))
+            foldmap[nf] = f
+
+    # check collision in provisional merged manifest
+    if normcase:
+        def normiter():
+            for f in pmmf:
+                yield normcase(f)
+        dirs = scmutil.dirs(normiter())
+        for f in sorted(pmmf):
+            check(f, normcase(f))
+    else:
+        dirs = scmutil.dirs(pmmf)
+        for f in sorted(pmmf):
+            check(f, f)
 
 def manifestmerge(repo, wctx, p2, pa, branchmerge, force, partial,
                   acceptremote=False):
@@ -350,13 +372,15 @@
         raise util.Abort(_("untracked files in working directory differ "
                            "from files in requested revision"))
 
-    if not util.checkcase(repo.path):
-        # check collision between files only in p2 for clean update
-        if (not branchmerge and
-            (force or not wctx.dirty(missing=True, branch=False))):
-            _checkcollision(repo, m2, [], [])
-        else:
-            _checkcollision(repo, m1, actions, prompts)
+    checkcase = util.checkcase(repo.path)
+    if (not branchmerge and
+        (force or not wctx.dirty(missing=True, branch=False))):
+        if not checkcase:
+            # check is not needed on case sensitive filesystem,
+            # because clean updating should not cause collision
+            _checkcollision(repo, m2, [], [], checkcase)
+    else:
+        _checkcollision(repo, m1, actions, prompts, checkcase)
 
     for f, m in sorted(prompts):
         if m == "cd":
diff --git a/tests/test-audit-path.t b/tests/test-audit-path.t
--- a/tests/test-audit-path.t
+++ b/tests/test-audit-path.t
@@ -62,7 +62,7 @@
   $ hg manifest -r2
   back
   back/test
-#if symlink
+#if symlink no-icasefs
   $ hg update -Cr2
   abort: path 'back/test' traverses symbolic link 'back'
   [255]
diff --git a/tests/test-casecollision-merge.t b/tests/test-casecollision-merge.t
--- a/tests/test-casecollision-merge.t
+++ b/tests/test-casecollision-merge.t
@@ -191,6 +191,29 @@
   M x
   C A
 
+Test for issue29: collision between file and directory, of which names
+are different from each other only in the letter case, should be
+detected on case insensitive filesystem.
+
+  $ hg update -q --clean 2
+  $ mkdir X
+  $ echo X/X > X/X
+  $ hg add X/X
+  $ hg commit -m '#5'
+  $ hg manifest -r 5
+  A
+  X/X
+  $ hg manifest -r 3
+  a
+  x
+  $ hg merge 3
+  abort: collision between file x and other directory
+  [255]
+  $ hg update -q --clean 3
+  $ hg merge 5
+  abort: collision between file x and other directory
+  [255]
+
   $ cd ..
 
 
diff --git a/tests/test-merge1.t b/tests/test-merge1.t
--- a/tests/test-merge1.t
+++ b/tests/test-merge1.t
@@ -173,4 +173,27 @@
   $ hg revert -r -2 b
   $ hg up -q -- -2
 
+Test for issue29
+
+  $ hg update -q -C 2
+  $ mkdir c
+  $ echo c/c > c/c
+  $ hg add c/c
+  $ hg ci -m "add c/c"
+  $ hg manifest -r 5
+  a
+  b
+  c/c
+  $ hg manifest -r 3
+  a
+  b
+  c
+  $ hg merge 3
+  abort: collision between file c and other directory
+  [255]
+  $ hg update -q -C 3
+  $ hg merge 5
+  abort: collision between file c and other directory
+  [255]
+
   $ cd ..