mdiff: adjust hunk offsets with --ignore-blank-lines (issue3234)

When diffing the following documents with --ignore-blank-lines (-B):

  $ cat > a <<EOF
  >
  >
  >
  > b
  > x
  > d
  > EOF

and:

  $ cat > b <<EOF
  > b
  > y
  > d
  > EOF

the context lines are taken from the first document, even if the lines differ
(with -w or -b) or if the number of lines differ (with -B). In the second case,
we have to adjust the hunk new lines offsets or we end with inconsistent diffs
like (see the @@ offsets):

  diff -r 0e66aa54f318 a
  --- a/a
  +++ b/a
  @@ -1,4 +1,3 @@

   b
  -x
  +y
   d

Note that having different context lines in a and b means the diff can be
applied but is not invertible.

Reported by Nicholas Riley <[e-mail]>

mercurial/mdiff.py

@@ -1,333 +1,342 b''
 # mdiff.py - diff and patch routines for mercurial
 #
 # Copyright 2005, 2006 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from i18n import _
 import bdiff, mpatch, util
 import re, struct
 
 def splitnewlines(text):
     '''like str.splitlines, but only split on newlines.'''
     lines = [l + '\n' for l in text.split('\n')]
     if lines:
         if lines[-1] == '\n':
             lines.pop()
         else:
             lines[-1] = lines[-1][:-1]
     return lines
 
 class diffopts(object):
     '''context is the number of context lines
     text treats all files as text
     showfunc enables diff -p output
     git enables the git extended patch format
     nodates removes dates from diff headers
     ignorews ignores all whitespace changes in the diff
     ignorewsamount ignores changes in the amount of whitespace
     ignoreblanklines ignores changes whose lines are all blank
     upgrade generates git diffs to avoid data loss
     '''
 
     defaults = {
         'context': 3,
         'text': False,
         'showfunc': False,
         'git': False,
         'nodates': False,
         'ignorews': False,
         'ignorewsamount': False,
         'ignoreblanklines': False,
         'upgrade': False,
         }
 
     __slots__ = defaults.keys()
 
     def __init__(self, **opts):
         for k in self.__slots__:
             v = opts.get(k)
             if v is None:
                 v = self.defaults[k]
             setattr(self, k, v)
 
         try:
             self.context = int(self.context)
         except ValueError:
             raise util.Abort(_('diff context lines count must be '
                                'an integer, not %r') % self.context)
 
     def copy(self, **kwargs):
         opts = dict((k, getattr(self, k)) for k in self.defaults)
         opts.update(kwargs)
         return diffopts(**opts)
 
 defaultopts = diffopts()
 
 def wsclean(opts, text, blank=True):
     if opts.ignorews:
         text = bdiff.fixws(text, 1)
     elif opts.ignorewsamount:
         text = bdiff.fixws(text, 0)
     if blank and opts.ignoreblanklines:
         text = re.sub('\n+', '\n', text).strip('\n')
     return text
 
 def splitblock(base1, lines1, base2, lines2, opts):
     # The input lines matches except for interwoven blank lines. We
     # transform it into a sequence of matching blocks and blank blocks.
     lines1 = [(wsclean(opts, l) and 1 or 0) for l in lines1]
     lines2 = [(wsclean(opts, l) and 1 or 0) for l in lines2]
     s1, e1 = 0, len(lines1)
     s2, e2 = 0, len(lines2)
     while s1 < e1 or s2 < e2:
         i1, i2, btype = s1, s2, '='
         if (i1 >= e1 or lines1[i1] == 0
             or i2 >= e2 or lines2[i2] == 0):
             # Consume the block of blank lines
             btype = '~'
             while i1 < e1 and lines1[i1] == 0:
                 i1 += 1
             while i2 < e2 and lines2[i2] == 0:
                 i2 += 1
         else:
             # Consume the matching lines
             while i1 < e1 and lines1[i1] == 1 and lines2[i2] == 1:
                 i1 += 1
                 i2 += 1
         yield [base1 + s1, base1 + i1, base2 + s2, base2 + i2], btype
         s1 = i1
         s2 = i2
 
 def allblocks(text1, text2, opts=None, lines1=None, lines2=None, refine=False):
     """Return (block, type) tuples, where block is an mdiff.blocks
     line entry. type is '=' for blocks matching exactly one another
     (bdiff blocks), '!' for non-matching blocks and '~' for blocks
     matching only after having filtered blank lines. If refine is True,
     then '~' blocks are refined and are only made of blank lines.
     line1 and line2 are text1 and text2 split with splitnewlines() if
     they are already available.
     """
     if opts is None:
         opts = defaultopts
     if opts.ignorews or opts.ignorewsamount:
         text1 = wsclean(opts, text1, False)
         text2 = wsclean(opts, text2, False)
     diff = bdiff.blocks(text1, text2)
     for i, s1 in enumerate(diff):
         # The first match is special.
         # we've either found a match starting at line 0 or a match later
         # in the file.  If it starts later, old and new below will both be
         # empty and we'll continue to the next match.
         if i > 0:
             s = diff[i - 1]
         else:
             s = [0, 0, 0, 0]
         s = [s[1], s1[0], s[3], s1[2]]
 
         # bdiff sometimes gives huge matches past eof, this check eats them,
         # and deals with the special first match case described above
         if s[0] != s[1] or s[2] != s[3]:
             type = '!'
             if opts.ignoreblanklines:
                 if lines1 is None:
                     lines1 = splitnewlines(text1)
                 if lines2 is None:
                     lines2 = splitnewlines(text2)
                 old = wsclean(opts, "".join(lines1[s[0]:s[1]]))
                 new = wsclean(opts, "".join(lines2[s[2]:s[3]]))
                 if old == new:
                     type = '~'
             yield s, type
         yield s1, '='
 
 def diffline(revs, a, b, opts):
     parts = ['diff']
     if opts.git:
         parts.append('--git')
     if revs and not opts.git:
         parts.append(' '.join(["-r %s" % rev for rev in revs]))
     if opts.git:
         parts.append('a/%s' % a)
         parts.append('b/%s' % b)
     else:
         parts.append(a)
     return ' '.join(parts) + '\n'
 
 def unidiff(a, ad, b, bd, fn1, fn2, r=None, opts=defaultopts):
     def datetag(date, addtab=True):
         if not opts.git and not opts.nodates:
             return '\t%s\n' % date
         if addtab and ' ' in fn1:
             return '\t\n'
         return '\n'
 
     if not a and not b:
         return ""
     epoch = util.datestr((0, 0))
 
     fn1 = util.pconvert(fn1)
     fn2 = util.pconvert(fn2)
 
     if not opts.text and (util.binary(a) or util.binary(b)):
         if a and b and len(a) == len(b) and a == b:
             return ""
         l = ['Binary file %s has changed\n' % fn1]
     elif not a:
         b = splitnewlines(b)
         if a is None:
             l1 = '--- /dev/null%s' % datetag(epoch, False)
         else:
             l1 = "--- %s%s" % ("a/" + fn1, datetag(ad))
         l2 = "+++ %s%s" % ("b/" + fn2, datetag(bd))
         l3 = "@@ -0,0 +1,%d @@\n" % len(b)
         l = [l1, l2, l3] + ["+" + e for e in b]
     elif not b:
         a = splitnewlines(a)
         l1 = "--- %s%s" % ("a/" + fn1, datetag(ad))
         if b is None:
             l2 = '+++ /dev/null%s' % datetag(epoch, False)
         else:
             l2 = "+++ %s%s" % ("b/" + fn2, datetag(bd))
         l3 = "@@ -1,%d +0,0 @@\n" % len(a)
         l = [l1, l2, l3] + ["-" + e for e in a]
     else:
         al = splitnewlines(a)
         bl = splitnewlines(b)
         l = list(_unidiff(a, b, al, bl, opts=opts))
         if not l:
             return ""
 
         l.insert(0, "--- a/%s%s" % (fn1, datetag(ad)))
         l.insert(1, "+++ b/%s%s" % (fn2, datetag(bd)))
 
     for ln in xrange(len(l)):
         if l[ln][-1] != '\n':
             l[ln] += "\n\ No newline at end of file\n"
 
     if r:
         l.insert(0, diffline(r, fn1, fn2, opts))
 
     return "".join(l)
 
 # creates a headerless unified diff
 # t1 and t2 are the text to be diffed
 # l1 and l2 are the text broken up into lines
 def _unidiff(t1, t2, l1, l2, opts=defaultopts):
     def contextend(l, len):
         ret = l + opts.context
         if ret > len:
             ret = len
         return ret
 
     def contextstart(l):
         ret = l - opts.context
         if ret < 0:
             return 0
         return ret
 
     lastfunc = [0, '']
     def yieldhunk(hunk):
         (astart, a2, bstart, b2, delta) = hunk
         aend = contextend(a2, len(l1))
         alen = aend - astart
         blen = b2 - bstart + aend - a2
 
         func = ""
         if opts.showfunc:
             lastpos, func = lastfunc
             # walk backwards from the start of the context up to the start of
             # the previous hunk context until we find a line starting with an
             # alphanumeric char.
             for i in xrange(astart - 1, lastpos - 1, -1):
                 if l1[i][0].isalnum():
                     func = ' ' + l1[i].rstrip()[:40]
                     lastfunc[1] = func
                     break
             # by recording this hunk's starting point as the next place to
             # start looking for function lines, we avoid reading any line in
             # the file more than once.
             lastfunc[0] = astart
 
         # zero-length hunk ranges report their start line as one less
         if alen:
             astart += 1
         if blen:
             bstart += 1
 
         yield "@@ -%d,%d +%d,%d @@%s\n" % (astart, alen,
                                            bstart, blen, func)
         for x in delta:
             yield x
         for x in xrange(a2, aend):
             yield ' ' + l1[x]
 
     # bdiff.blocks gives us the matching sequences in the files.  The loop
     # below finds the spaces between those matching sequences and translates
     # them into diff output.
     #
     hunk = None
+    ignoredlines = 0
     for s, stype in allblocks(t1, t2, opts, l1, l2):
+        a1, a2, b1, b2 = s
         if stype != '!':
+            if stype == '~':
+                # The diff context lines are based on t1 content. When
+                # blank lines are ignored, the new lines offsets must
+                # be adjusted as if equivalent blocks ('~') had the
+                # same sizes on both sides.
+                ignoredlines += (b2 - b1) - (a2 - a1)
             continue
         delta = []
-        a1, a2, b1, b2 = s
         old = l1[a1:a2]
         new = l2[b1:b2]
 
+        b1 -= ignoredlines
+        b2 -= ignoredlines
         astart = contextstart(a1)
         bstart = contextstart(b1)
         prev = None
         if hunk:
             # join with the previous hunk if it falls inside the context
             if astart < hunk[1] + opts.context + 1:
                 prev = hunk
                 astart = hunk[1]
                 bstart = hunk[3]
             else:
                 for x in yieldhunk(hunk):
                     yield x
         if prev:
             # we've joined the previous hunk, record the new ending points.
             hunk[1] = a2
             hunk[3] = b2
             delta = hunk[4]
         else:
             # create a new hunk
             hunk = [astart, a2, bstart, b2, delta]
 
         delta[len(delta):] = [' ' + x for x in l1[astart:a1]]
         delta[len(delta):] = ['-' + x for x in old]
         delta[len(delta):] = ['+' + x for x in new]
 
     if hunk:
         for x in yieldhunk(hunk):
             yield x
 
 def patchtext(bin):
     pos = 0
     t = []
     while pos < len(bin):
         p1, p2, l = struct.unpack(">lll", bin[pos:pos + 12])
         pos += 12
         t.append(bin[pos:pos + l])
         pos += l
     return "".join(t)
 
 def patch(a, bin):
     if len(a) == 0:
         # skip over trivial delta header
         return util.buffer(bin, 12)
     return mpatch.patches(a, [bin])
 
 # similar to difflib.SequenceMatcher.get_matching_blocks
 def get_matching_blocks(a, b):
     return [(d[0], d[2], d[1] - d[0]) for d in bdiff.blocks(a, b)]
 
 def trivialdiffheader(length):
     return struct.pack(">lll", 0, 0, length)
 
 patches = mpatch.patches
 patchedsize = mpatch.patchedsize
 textdiff = bdiff.bdiff

tests/test-diff-ignore-whitespace.t

@@ -1,457 +1,500 b''
 GNU diff is the reference for all of these results.
 
 Prepare tests:
 
   $ echo '[alias]' >> $HGRCPATH
   $ echo 'ndiff = diff --nodates' >> $HGRCPATH
 
   $ hg init
   $ printf 'hello world\ngoodbye world\n' >foo
   $ hg ci -Amfoo -ufoo
   adding foo
 
 
 Test added blank lines:
 
   $ printf '\nhello world\n\ngoodbye world\n\n' >foo
 
 >>> two diffs showing three added lines <<<
 
   $ hg ndiff
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,5 @@
   +
    hello world
   +
    goodbye world
   +
   $ hg ndiff -b
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,5 @@
   +
    hello world
   +
    goodbye world
   +
 
 >>> no diffs <<<
 
   $ hg ndiff -B
   $ hg ndiff -Bb
 
 
 Test added horizontal space first on a line():
 
   $ printf '\t hello world\ngoodbye world\n' >foo
 
 >>> four diffs showing added space first on the first line <<<
 
   $ hg ndiff
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,2 @@
   -hello world
   +	 hello world
    goodbye world
 
   $ hg ndiff -b
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,2 @@
   -hello world
   +	 hello world
    goodbye world
 
   $ hg ndiff -B
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,2 @@
   -hello world
   +	 hello world
    goodbye world
 
   $ hg ndiff -Bb
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,2 @@
   -hello world
   +	 hello world
    goodbye world
 
 
 Test added horizontal space last on a line:
 
   $ printf 'hello world\t \ngoodbye world\n' >foo
 
 >>> two diffs showing space appended to the first line <<<
 
   $ hg ndiff
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,2 @@
   -hello world
   +hello world	 
    goodbye world
 
   $ hg ndiff -B
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,2 @@
   -hello world
   +hello world	 
    goodbye world
 
 >>> no diffs <<<
 
   $ hg ndiff -b
   $ hg ndiff -Bb
 
 
 Test added horizontal space in the middle of a word:
 
   $ printf 'hello world\ngood bye world\n' >foo
 
 >>> four diffs showing space inserted into "goodbye" <<<
 
   $ hg ndiff
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,2 @@
    hello world
   -goodbye world
   +good bye world
 
   $ hg ndiff -B
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,2 @@
    hello world
   -goodbye world
   +good bye world
 
   $ hg ndiff -b
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,2 @@
    hello world
   -goodbye world
   +good bye world
 
   $ hg ndiff -Bb
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,2 @@
    hello world
   -goodbye world
   +good bye world
 
 
 Test increased horizontal whitespace amount:
 
   $ printf 'hello world\ngoodbye\t\t  \tworld\n' >foo
 
 >>> two diffs showing changed whitespace amount in the last line <<<
 
   $ hg ndiff
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,2 @@
    hello world
   -goodbye world
   +goodbye		  	world
 
   $ hg ndiff -B
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,2 @@
    hello world
   -goodbye world
   +goodbye		  	world
 
 >>> no diffs <<<
 
   $ hg ndiff -b
   $ hg ndiff -Bb
 
 
 Test added blank line with horizontal whitespace:
 
   $ printf 'hello world\n \t\ngoodbye world\n' >foo
 
 >>> three diffs showing added blank line with horizontal space <<<
 
   $ hg ndiff
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,3 @@
    hello world
   + 	
    goodbye world
 
   $ hg ndiff -B
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,3 @@
    hello world
   + 	
    goodbye world
 
   $ hg ndiff -b
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,3 @@
    hello world
   + 	
    goodbye world
 
 >>> no diffs <<<
 
   $ hg ndiff -Bb
 
 
 Test added blank line with other whitespace:
 
   $ printf 'hello  world\n \t\ngoodbye world \n' >foo
 
 >>> three diffs showing added blank line with other space <<<
 
   $ hg ndiff
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,3 @@
   -hello world
   -goodbye world
   +hello  world
   + 	
   +goodbye world 
 
   $ hg ndiff -B
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,3 @@
   -hello world
   -goodbye world
   +hello  world
   + 	
   +goodbye world 
 
   $ hg ndiff -b
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,3 @@
    hello world
   + 	
    goodbye world
 
 >>> no diffs <<<
 
   $ hg ndiff -Bb
 
 
 Test whitespace changes:
 
   $ printf 'helloworld\ngoodbye\tworld \n' >foo
 
 >>> four diffs showing changed whitespace <<<
 
   $ hg ndiff
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,2 @@
   -hello world
   -goodbye world
   +helloworld
   +goodbye	world 
 
   $ hg ndiff -B
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,2 @@
   -hello world
   -goodbye world
   +helloworld
   +goodbye	world 
 
   $ hg ndiff -b
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,2 @@
   -hello world
   +helloworld
    goodbye world
 
   $ hg ndiff -Bb
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,2 @@
   -hello world
   +helloworld
    goodbye world
 
 >>> no diffs <<<
 
   $ hg ndiff -w
 
 
 Test whitespace changes and blank lines:
 
   $ printf 'helloworld\n\n\n\ngoodbye\tworld \n' >foo
 
 >>> five diffs showing changed whitespace <<<
 
   $ hg ndiff
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,5 @@
   -hello world
   -goodbye world
   +helloworld
   +
   +
   +
   +goodbye	world 
 
   $ hg ndiff -B
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,5 @@
   -hello world
   -goodbye world
   +helloworld
   +
   +
   +
   +goodbye	world 
 
   $ hg ndiff -b
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,5 @@
   -hello world
   +helloworld
   +
   +
   +
    goodbye world
 
   $ hg ndiff -Bb
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,5 @@
   -hello world
   +helloworld
   +
   +
   +
    goodbye world
 
   $ hg ndiff -w
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,5 @@
    hello world
   +
   +
   +
    goodbye world
 
 >>> no diffs <<<
 
   $ hg ndiff -wB
 
 
 Test \r (carriage return) as used in "DOS" line endings:
 
   $ printf 'hello world\r\n\r\ngoodbye\rworld\n' >foo
 
   $ hg ndiff
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,3 @@
   -hello world
   -goodbye world
   +hello world\r (esc)
   +\r (esc)
   +goodbye\rworld (esc)
 
 No completely blank lines to ignore:
 
   $ hg ndiff --ignore-blank-lines
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,3 @@
   -hello world
   -goodbye world
   +hello world\r (esc)
   +\r (esc)
   +goodbye\rworld (esc)
 
 Only new line noticed:
 
   $ hg ndiff --ignore-space-change
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,3 @@
    hello world
   +\r (esc)
    goodbye world
 
   $ hg ndiff --ignore-all-space
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,3 @@
    hello world
   +\r (esc)
    goodbye world
 
 New line not noticed when space change ignored:
 
   $ hg ndiff --ignore-blank-lines --ignore-all-space
 
 Do not ignore all newlines, only blank lines
 
   $ printf 'hello \nworld\ngoodbye world\n' > foo
   $ hg ndiff --ignore-blank-lines
   diff -r 540c40a65b78 foo
   --- a/foo
   +++ b/foo
   @@ -1,2 +1,3 @@
   -hello world
   +hello 
   +world
    goodbye world
+
+Test hunk offsets adjustments with --ignore-blank-lines
+
+  $ hg revert -aC
+  reverting foo
+  $ printf '\nb\nx\nd\n' > a
+  $ printf 'b\ny\nd\n' > b
+  $ hg add a b
+  $ hg ci -m add
+  $ hg cat -r . a > b
+  $ hg cat -r . b > a
+  $ hg diff -B --nodates a > ../diffa
+  $ cat ../diffa
+  diff -r 0e66aa54f318 a
+  --- a/a
+  +++ b/a
+  @@ -1,4 +1,4 @@
+   
+   b
+  -x
+  +y
+   d
+  $ hg diff -B --nodates b > ../diffb
+  $ cat ../diffb
+  diff -r 0e66aa54f318 b
+  --- a/b
+  +++ b/b
+  @@ -1,3 +1,3 @@
+   b
+  -y
+  +x
+   d
+  $ hg revert -aC
+  reverting a
+  reverting b
+  $ hg import --no-commit ../diffa
+  applying ../diffa
+  $ hg revert -aC
+  reverting a
+  $ hg import --no-commit ../diffb
+  applying ../diffb
+  $ hg revert -aC
+  reverting b

tests/test-mq-qdiff.t

@@ -1,175 +1,175 b''
   $ echo "[extensions]" >> $HGRCPATH
   $ echo "mq=" >> $HGRCPATH
   $ echo "[mq]" >> $HGRCPATH
   $ echo "git=keep" >> $HGRCPATH
 
   $ hg init a
   $ cd a
 
   $ echo 'base' > base
   $ hg ci -Ambase
   adding base
 
   $ hg qnew -mmqbase mqbase
 
   $ echo 'patched' > base
   $ hg qrefresh
 
 qdiff:
 
   $ hg qdiff
   diff -r d20a80d4def3 base
   --- a/base	Thu Jan 01 00:00:00 1970 +0000
   +++ b/base* (glob)
   @@ -1,1 +1,1 @@
   -base
   +patched
 
 qdiff dirname:
 
   $ hg qdiff --nodates .
   diff -r d20a80d4def3 base
   --- a/base
   +++ b/base
   @@ -1,1 +1,1 @@
   -base
   +patched
 
 qdiff filename:
 
   $ hg qdiff --nodates base
   diff -r d20a80d4def3 base
   --- a/base
   +++ b/base
   @@ -1,1 +1,1 @@
   -base
   +patched
 
   $ hg revert -a
 
   $ hg qpop
   popping mqbase
   patch queue now empty
 
   $ hg qdelete mqbase
 
   $ printf '1\n2\n3\n4\nhello world\ngoodbye world\n7\n8\n9\n' > lines
   $ hg ci -Amlines -d '2 0'
   adding lines
 
   $ hg qnew -mmqbase2 mqbase2
   $ printf '\n\n1\n2\n3\n4\nhello  world\n     goodbye world\n7\n8\n9\n' > lines
 
   $ hg qdiff --nodates -U 1
   diff -r b0c220e1cf43 lines
   --- a/lines
   +++ b/lines
   @@ -1,1 +1,3 @@
   +
   +
    1
   @@ -4,4 +6,4 @@
    4
   -hello world
   -goodbye world
   +hello  world
   +     goodbye world
    7
 
   $ hg qdiff --nodates -b
   diff -r b0c220e1cf43 lines
   --- a/lines
   +++ b/lines
   @@ -1,9 +1,11 @@
   +
   +
    1
    2
    3
    4
    hello world
   -goodbye world
   +     goodbye world
    7
    8
    9
 
   $ hg qdiff --nodates -U 1 -B
   diff -r b0c220e1cf43 lines
   --- a/lines
   +++ b/lines
-  @@ -4,4 +6,4 @@
+  @@ -4,4 +4,4 @@
    4
   -hello world
   -goodbye world
   +hello  world
   +     goodbye world
    7
 
   $ hg qdiff --nodates -w
   diff -r b0c220e1cf43 lines
   --- a/lines
   +++ b/lines
   @@ -1,3 +1,5 @@
   +
   +
    1
    2
    3
 
   $ hg qdiff --nodates --reverse
   diff -r b0c220e1cf43 lines
   --- a/lines
   +++ b/lines
   @@ -1,11 +1,9 @@
   -
   -
    1
    2
    3
    4
   -hello  world
   -     goodbye world
   +hello world
   +goodbye world
    7
    8
    9
 
 qdiff preserve existing git flag:
 
   $ hg qrefresh --git
   $ echo a >> lines
   $ hg qdiff
   diff --git a/lines b/lines
   --- a/lines
   +++ b/lines
   @@ -1,9 +1,12 @@
   +
   +
    1
    2
    3
    4
   -hello world
   -goodbye world
   +hello  world
   +     goodbye world
    7
    8
    9
   +a
 
   $ hg qdiff --stat
    lines |  7 +++++--
    1 files changed, 5 insertions(+), 2 deletions(-)
   $ hg qrefresh
 
 qdiff when file deleted (but not removed) in working dir:
 
   $ hg qnew deleted-file
   $ echo a > newfile
   $ hg add newfile
   $ hg qrefresh
   $ rm newfile
   $ hg qdiff