Refactor excessive merge detection, add test

tests/test-excessive-merge

@@ -0,0 +1,46 b''
+#!/bin/sh
+
+hg init
+
+echo foo > a
+echo foo > b
+hg add a b
+
+hg ci -m "test" -d "0 0"
+
+echo blah > a
+
+hg ci -m "branch a" -d "0 0"
+
+hg co 0
+
+echo blah > b
+
+hg ci -m "branch b" -d "0 0"
+HGMERGE=true hg up -m 1
+
+hg ci -m "merge b/a -> blah" -d "0 0"
+
+hg co 1
+HGMERGE=true hg up -m 2
+hg ci -m "merge a/b -> blah" -d "0 0"
+
+hg log
+hg debugindex .hg/00changelog.i
+
+echo
+
+echo 1
+hg manifest 1
+echo 2
+hg manifest 2
+echo 3
+hg manifest 3
+echo 4
+hg manifest 4
+
+echo
+
+hg debugindex .hg/data/a.i
+
+hg verify
  No newline at end of file

tests/test-excessive-merge.out

@@ -0,0 +1,59 b''
+changeset:   4:2ee31f665a86
+tag:         tip
+parent:      1:96155394af80
+parent:      2:92cc4c306b19
+user:        test
+date:        Thu Jan  1 00:00:00 1970 +0000
+summary:     merge a/b -> blah
+
+changeset:   3:e16a66a37edd
+parent:      2:92cc4c306b19
+parent:      1:96155394af80
+user:        test
+date:        Thu Jan  1 00:00:00 1970 +0000
+summary:     merge b/a -> blah
+
+changeset:   2:92cc4c306b19
+parent:      0:5e0375449e74
+user:        test
+date:        Thu Jan  1 00:00:00 1970 +0000
+summary:     branch b
+
+changeset:   1:96155394af80
+user:        test
+date:        Thu Jan  1 00:00:00 1970 +0000
+summary:     branch a
+
+changeset:   0:5e0375449e74
+user:        test
+date:        Thu Jan  1 00:00:00 1970 +0000
+summary:     test
+
+   rev    offset  length   base linkrev nodeid       p1           p2
+     0         0      60      0       0 5e0375449e74 000000000000 000000000000
+     1        60      62      1       1 96155394af80 5e0375449e74 000000000000
+     2       122      62      2       2 92cc4c306b19 5e0375449e74 000000000000
+     3       184      69      3       3 e16a66a37edd 92cc4c306b19 96155394af80
+     4       253      29      3       4 2ee31f665a86 96155394af80 92cc4c306b19
+
+1
+79d7492df40aa0fa093ec4209be78043c181f094 644 a
+2ed2a3912a0b24502043eae84ee4b279c18b90dd 644 b
+2
+2ed2a3912a0b24502043eae84ee4b279c18b90dd 644 a
+79d7492df40aa0fa093ec4209be78043c181f094 644 b
+3
+79d7492df40aa0fa093ec4209be78043c181f094 644 a
+79d7492df40aa0fa093ec4209be78043c181f094 644 b
+4
+79d7492df40aa0fa093ec4209be78043c181f094 644 a
+79d7492df40aa0fa093ec4209be78043c181f094 644 b
+
+   rev    offset  length   base linkrev nodeid       p1           p2
+     0         0       5      0       0 2ed2a3912a0b 000000000000 000000000000
+     1         5       6      1       1 79d7492df40a 2ed2a3912a0b 000000000000
+checking changesets
+checking manifests
+crosschecking files in changesets and manifests
+checking files
+2 files, 5 changesets, 4 total revisions

mercurial/localrepo.py

@@ -268,6 +268,25 b' class localrepository(object):'
         self.dirstate.read()
         return wlock
 
+    def checkfilemerge(self, filename, text, filelog, manifest1, manifest2):
+        "determine whether a new filenode is needed"
+        fp1 = manifest1.get(filename, nullid)
+        fp2 = manifest2.get(filename, nullid)
+
+        if fp2 != nullid:
+            # is one parent an ancestor of the other?
+            fpa = filelog.ancestor(fp1, fp2)
+            if fpa == fp1:
+                fp1, fp2 = fp2, nullid
+            elif fpa == fp2:
+                fp2 = nullid
+
+            # is the file unmodified from the parent? report existing entry
+            if fp2 == nullid and text == filelog.read(fp1):
+                return (fp1, None, None)
+
+        return (None, fp1, fp2)
+
     def rawcommit(self, files, text, user, date, p1=None, p2=None, wlock=None):
         orig_parent = self.dirstate.parents()[0] or nullid
         p1 = p1 or self.dirstate.parents()[0] or nullid
@@ -298,27 +317,10 b' class localrepository(object):'
                 r = self.file(f)
                 mfm[f] = tm
 
-                fp1 = m1.get(f, nullid)
-                fp2 = m2.get(f, nullid)
-
-                # is the same revision on two branches of a merge?
-                if fp2 == fp1:
-                    fp2 = nullid
-
-                if fp2 != nullid:
-                    # is one parent an ancestor of the other?
-                    fpa = r.ancestor(fp1, fp2)
-                    if fpa == fp1:
-                        fp1, fp2 = fp2, nullid
-                    elif fpa == fp2:
-                        fp2 = nullid
-
-                    # is the file unmodified from the parent?
-                    if t == r.read(fp1):
-                        # record the proper existing parent in manifest
-                        # no need to add a revision
-                        mm[f] = fp1
-                        continue
+                (entry, fp1, fp2) = self.checkfilemerge(f, t, r, m1, m2)
+                if entry:
+                    mm[f] = entry
+                    continue
 
                 mm[f] = r.add(t, {}, tr, linkrev, fp1, fp2)
                 changed.append(f)
@@ -403,22 +405,9 b' class localrepository(object):'
                 self.ui.debug(_(" %s: copy %s:%s\n") % (f, cp, meta["copyrev"]))
                 fp1, fp2 = nullid, nullid
             else:
-                fp1 = m1.get(f, nullid)
-                fp2 = m2.get(f, nullid)
-
-            if fp2 != nullid:
-                # is one parent an ancestor of the other?
-                fpa = r.ancestor(fp1, fp2)
-                if fpa == fp1:
-                    fp1, fp2 = fp2, nullid
-                elif fpa == fp2:
-                    fp2 = nullid
-
-                # is the file unmodified from the parent?
-                if not meta and t == r.read(fp1) and fp2 == nullid:
-                    # record the proper existing parent in manifest
-                    # no need to add a revision
-                    new[f] = fp1
+                entry, fp1, fp2 = self.checkfilemerge(f, t, r, m1, m2)
+                if entry:
+                    new[f] = entry
                     continue
 
             new[f] = r.add(t, meta, tr, linkrev, fp1, fp2)