--- a/mercurial/mdiff.py	Wed May 10 19:23:19 2006 +0200
+++ b/mercurial/mdiff.py	Wed May 10 10:32:24 2006 -0700
@@ -10,6 +10,20 @@
 demandload(globals(), "re")
 
 
+def splitnewlines(text, keepends=False):
+    '''like str.splitlines, but only split on newlines.'''
+    i = 0
+    lines = []
+    while True:
+        n = text.find('\n', i)
+        if n == -1:
+            last = text[i:]
+            if last:
+                lines.append(last)
+            return lines
+        lines.append(text[i:keepends and n+1 or n])
+        i = n + 1
+
 def unidiff(a, ad, b, bd, fn, r=None, text=False,
             showfunc=False, ignorews=False):
 
@@ -19,7 +33,7 @@
     if not text and (util.binary(a) or util.binary(b)):
         l = ['Binary file %s has changed\n' % fn]
     elif not a:
-        b = b.splitlines(1)
+        b = splitnewlines(b, keepends=True)
         if a is None:
             l1 = "--- %s\t%s\n" % ("/dev/null", epoch)
         else:
@@ -28,7 +42,7 @@
         l3 = "@@ -0,0 +1,%d @@\n" % len(b)
         l = [l1, l2, l3] + ["+" + e for e in b]
     elif not b:
-        a = a.splitlines(1)
+        a = splitnewlines(a, keepends=True)
         l1 = "--- %s\t%s\n" % ("a/" + fn, ad)
         if b is None:
             l2 = "+++ %s\t%s\n" % ("/dev/null", epoch)
@@ -37,8 +51,8 @@
         l3 = "@@ -1,%d +0,0 @@\n" % len(a)
         l = [l1, l2, l3] + ["-" + e for e in a]
     else:
-        al = a.splitlines(1)
-        bl = b.splitlines(1)
+        al = splitnewlines(a, keepends=True)
+        bl = splitnewlines(b, keepends=True)
         l = list(bunidiff(a, b, al, bl, "a/" + fn, "b/" + fn,
                           showfunc=showfunc, ignorews=ignorews))
         if not l: return ""

--- a/tests/run-tests.py	Wed May 10 19:23:19 2006 +0200
+++ b/tests/run-tests.py	Wed May 10 10:32:24 2006 -0700
@@ -34,10 +34,25 @@
             print m,
         print
 
+def splitnewlines(text):
+    '''like str.splitlines, but only split on newlines.
+    keep line endings.'''
+    i = 0
+    lines = []
+    while True:
+        n = text.find('\n', i)
+        if n == -1:
+            last = text[i:]
+            if last:
+                lines.append(last)
+            return lines
+        lines.append(text[i:n+1])
+        i = n + 1
+
 def show_diff(expected, output):
     for line in difflib.unified_diff(expected, output,
             "Expected output", "Test output", lineterm=''):
-        print line
+        sys.stdout.write(line)
 
 def find_program(program):
     """Search PATH for a executable program"""
@@ -125,7 +140,7 @@
         vlog("# Running: "+cmd)
         os.system(cmd)
 
-def run(cmd, split_lines=True):
+def run(cmd):
     """Run command in a sub-process, capturing the output (stdout and stderr).
     Return the exist code, and output."""
     # TODO: Use subprocess.Popen if we're running on Python 2.4
@@ -141,9 +156,7 @@
         proc.tochild.close()
         output = proc.fromchild.read()
         ret = proc.wait()
-    if split_lines:
-        output = output.splitlines()
-    return ret, output
+    return ret, splitnewlines(output)
 
 def run_one(test):
     vlog("# Test", test)
@@ -180,22 +193,23 @@
     # If reference output file exists, check test output against it
     if os.path.exists(ref):
         f = open(ref, "r")
-        ref_out = f.read().splitlines()
+        ref_out = splitnewlines(f.read())
         f.close()
-        if out != ref_out:
-            diffret = 1
-            print "\nERROR: %s output changed" % (test)
-            show_diff(ref_out, out)
+    else:
+        ref_out = ['']
+    if out != ref_out:
+        diffret = 1
+        print "\nERROR: %s output changed" % (test)
+        show_diff(ref_out, out)
     if ret:
         print "\nERROR: %s failed with error code %d" % (test, ret)
     elif diffret:
         ret = diffret
 
     if ret != 0: # Save errors to a file for diagnosis
-        f = open(err, "w")
+        f = open(err, "wb")
         for line in out:
             f.write(line)
-            f.write("\n")
         f.close()
 
     os.chdir(TESTDIR)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test-diff-newlines	Wed May 10 10:32:24 2006 -0700
@@ -0,0 +1,8 @@
+#!/bin/sh
+
+hg init
+python -c 'print "confuse str.splitlines\nembedded\rnewline"' > a
+hg ci -Ama -d '1 0'
+echo clean diff >> a
+hg ci -mb -d '2 0'
+hg diff -r0 -r1

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test-diff-newlines.out	Wed May 10 10:32:24 2006 -0700
@@ -0,0 +1,8 @@
+adding a
+diff -r 107ba6f817b5 -r 310ce7989cdc a
+--- a/a	Thu Jan 01 00:00:01 1970 +0000
++++ b/a	Thu Jan 01 00:00:02 1970 +0000
+@@ -1,2 +1,3 @@ confuse str.splitlines
+ confuse str.splitlines
+ embedded
newline
++clean diff