diff mercurial/patch.py @ 10135:9a4034b630c4 stable

patch: better handling of sequence of offset patch hunks (issue1941)

The built-in patch implementation applied the hunks to the wrong lines of the
file if the file in the repo has been modified to skew the patch line numbers
and the file contains repetitive sequences of lines.

--- a/mercurial/patch.py	Wed Dec 23 20:31:35 2009 +0100
+++ b/mercurial/patch.py	Wed Dec 09 16:56:00 2009 -0800
@@ -286,6 +286,7 @@
         self.hash = {}
         self.dirty = 0
         self.offset = 0
+        self.skew = 0
         self.rej = []
         self.fileprinted = False
         self.printfile(False)
@@ -423,7 +424,10 @@
         else:
             start = h.starta + self.offset - 1
         orig_start = start
-        if diffhelpers.testhunk(old, self.lines, start) == 0:
+        # if there's skew we want to emit the "(offset %d lines)" even
+        # when the hunk cleanly applies at start + skew, so skip the
+        # fast case code
+        if self.skew == 0 and diffhelpers.testhunk(old, self.lines, start) == 0:
             if h.rmfile():
                 self.unlink(self.fname)
             else:
@@ -439,7 +443,7 @@
             # override the start line and use eof here
             search_start = len(self.lines)
         else:
-            search_start = orig_start
+            search_start = orig_start + self.skew
 
         for fuzzlen in xrange(3):
             for toponly in [ True, False ]:
@@ -451,6 +455,7 @@
                         newlines = h.new(fuzzlen, toponly)
                         self.lines[l : l + len(old)] = newlines
                         self.offset += len(newlines) - len(old)
+                        self.skew = l - orig_start
                         self.dirty = 1
                         if fuzzlen:
                             fuzzstr = "with fuzz %d " % fuzzlen