icasefs: make case-folding collision detection as rename aware (issue3370)

if the file in target context causes case-folding collision against
one in working context, current implementation aborts merging with it,
even thouhg collding one (in target) is the file renamed from collided
one (in working).

this patch uses file copy information to know whether colliding file
is renamed from collided one or not: if so, collision between them is
ignored.

this patch also avoids collision detection between current context and
target context, if working context is clean (with --check/-c) or will
be clean (with --clean/-C).

mercurial/merge.py

@@ -110,10 +110,18 b' def _checkcollision(mctx, wctx):'
         folded[fold] = fn
 
     if wctx:
+        # class to delay looking up copy mapping
+        class pathcopies(object):
+            @util.propertycache
+            def map(self):
+                # {dst@mctx: src@wctx} copy mapping
+                return copies.pathcopies(wctx, mctx)
+        pc = pathcopies()
+
         for fn in wctx:
             fold = util.normcase(fn)
             mfn = folded.get(fold, None)
-            if mfn and (mfn != fn):
+            if mfn and mfn != fn and pc.map.get(mfn) != fn:
                 raise util.Abort(_("case-folding collision between %s and %s")
                                  % (mfn, fn))
 
@@ -568,7 +576,11 b' def update(repo, node, branchmerge, forc'
         action = []
         folding = not util.checkcase(repo.path)
         if folding:
-            _checkcollision(p2, branchmerge and p1)
+            # collision check is not needed for clean update
+            if not branchmerge and force:
+                _checkcollision(p2, None)
+            else:
+                _checkcollision(p2, wc)
         if not force:
             _checkunknown(repo, wc, p2)
         action += _forgetremoved(wc, p2, branchmerge)

tests/test-casecollision-merge.t

@@ -6,104 +6,204 b' run only on case-insensitive filesystems'
 test for branch merging
 ################################
 
-  $ hg init repo1
-  $ cd repo1
-
-create base revision
+test for rename awareness of case-folding collision check:
 
-  $ echo base > base.txt
-  $ hg add base.txt
-  $ hg commit -m 'base'
+(1) colliding file is one renamed from collided file:
+this is also case for issue3370.
 
-add same file in different case on both heads
+  $ hg init merge_renameaware_1
+  $ cd merge_renameaware_1
 
-  $ echo a > a.txt
-  $ hg add a.txt
-  $ hg commit -m 'add a.txt'
-
+  $ echo a > a
+  $ hg add a
+  $ hg commit -m '#0'
+  $ hg rename a tmp
+  $ hg rename tmp A
+  $ hg commit -m '#1'
   $ hg update 0
-  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
-
-  $ echo A > A.TXT
-  $ hg add A.TXT
-  $ hg commit -m 'add A.TXT'
+  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ echo 'modified at #2' > a
+  $ hg commit -m '#2'
   created new head
 
-merge another, and fail with case-folding collision
+  $ hg merge
+  merging a and A to A
+  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
+  (branch merge, don't forget to commit)
+  $ hg status -A
+  M A
+    a
+  R a
+  $ cat A
+  modified at #2
+
+  $ hg update --clean 1
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg merge
+  merging A and a to A
+  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
+  (branch merge, don't forget to commit)
+  $ hg status -A
+  M A
+    a
+  $ cat A
+  modified at #2
+
+  $ cd ..
+
+(2) colliding file is not related to collided file
+
+  $ hg init merge_renameaware_2
+  $ cd merge_renameaware_2
+
+  $ echo a > a
+  $ hg add a
+  $ hg commit -m '#0'
+  $ hg remove a
+  $ hg commit -m '#1'
+  $ echo A > A
+  $ hg add A
+  $ hg commit -m '#2'
+  $ hg update --clean 0
+  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ echo 'modified at #3' > a
+  $ hg commit -m '#3'
+  created new head
 
   $ hg merge
-  abort: case-folding collision between a.txt and A.TXT
+  abort: case-folding collision between A and a
   [255]
+  $ hg parents --template '{rev}\n'
+  3
+  $ hg status -A
+  C a
+  $ cat a
+  modified at #3
 
-check clean-ness of working directory
-
-  $ hg status
+  $ hg update --clean 2
+  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ hg merge
+  abort: case-folding collision between a and A
+  [255]
   $ hg parents --template '{rev}\n'
   2
+  $ hg status -A
+  C A
+  $ cat A
+  A
+
   $ cd ..
 
+
 ################################
 test for linear updates
 ################################
 
-  $ hg init repo2
-  $ cd repo2
+test for rename awareness of case-folding collision check:
 
-create base revision (rev:0)
+(1) colliding file is one renamed from collided file
+
+  $ hg init linearupdate_renameaware_1
+  $ cd linearupdate_renameaware_1
 
-  $ hg import --bypass --exact - <<EOF
-  > # HG changeset patch
-  > # User null
-  > # Date 1 0
-  > # Node ID e1bdf414b0ea9c831fd3a14e94a0a18e1410f98b
-  > # Parent  0000000000000000000000000000000000000000
-  > add a
-  > 
-  > diff --git a/a b/a
-  > new file mode 100644
-  > --- /dev/null
-  > +++ b/a
-  > @@ -0,0 +1,3 @@
-  > +this is line 1
-  > +this is line 2
-  > +this is line 3
-  > EOF
-  applying patch from stdin
-
-create rename revision (rev:1)
-
-  $ hg import --bypass --exact - <<EOF
-  > # HG changeset patch
-  > # User null
-  > # Date 1 0
-  > # Node ID 9dca9f19bb91851bc693544b598b0740629edfad
-  > # Parent  e1bdf414b0ea9c831fd3a14e94a0a18e1410f98b
-  > rename a to A
-  > 
-  > diff --git a/a b/A
-  > rename from a
-  > rename to A
-  > EOF
-  applying patch from stdin
-
-update to base revision, and modify 'a'
+  $ echo a > a
+  $ hg add a
+  $ hg commit -m '#0'
+  $ hg rename a tmp
+  $ hg rename tmp A
+  $ hg commit -m '#1'
 
   $ hg update 0
-  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
-  $ echo 'this is added line' >> a
+  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
 
-update to current tip linearly
-
+  $ echo 'this is added line' >> a
   $ hg update 1
   merging a and A to A
   0 files updated, 1 files merged, 0 files removed, 0 files unresolved
-
-check status and contents of file
-
   $ hg status -A
   M A
   $ cat A
-  this is line 1
-  this is line 2
-  this is line 3
+  a
   this is added line
+
+  $ cd ..
+
+(2) colliding file is not related to collided file
+
+  $ hg init linearupdate_renameaware_2
+  $ cd linearupdate_renameaware_2
+
+  $ echo a > a
+  $ hg add a
+  $ hg commit -m '#0'
+  $ hg remove a
+  $ hg commit -m '#1'
+  $ echo A > A
+  $ hg add A
+  $ hg commit -m '#2'
+
+  $ hg update 0
+  abort: case-folding collision between a and A
+  [255]
+  $ hg parents --template '{rev}\n'
+  2
+  $ hg status -A
+  C A
+  $ cat A
+  A
+
+  $ hg update --check 0
+  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ hg parents --template '{rev}\n'
+  0
+  $ hg status -A
+  C a
+  $ cat a
+  a
+
+  $ hg update --clean 2
+  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ hg parents --template '{rev}\n'
+  2
+  $ hg status -A
+  C A
+  $ cat A
+  A
+
+  $ cd ..
+
+(3) colliding file is not related to collided file: added in working dir
+
+  $ hg init linearupdate_renameaware_3
+  $ cd linearupdate_renameaware_3
+
+  $ echo a > a
+  $ hg add a
+  $ hg commit -m '#0'
+  $ hg rename a b
+  $ hg commit -m '#1'
+  $ hg update 0
+  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
+
+  $ echo B > B
+  $ hg add B
+  $ hg status
+  A B
+  $ hg update
+  abort: case-folding collision between b and B
+  [255]
+
+  $ hg update --check
+  abort: uncommitted local changes
+  [255]
+
+  $ hg update --clean
+  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ hg parents --template '{rev}\n'
+  1
+  $ hg status -A
+  C b
+  $ cat b
+  a
+
+  $ cd ..