Squashed 'waflib/' changes from e7a29b6..cddbcb5

cddbcb5 Pass file comparison test if difflib finds no changes
6e4e92b Seek to end before checking the size of stderr output

git-subtree-dir: waflib
git-subtree-split: cddbcb577dad255414b6454d8680a6cd80ad7458

1 files changed, 7 insertions, 4 deletions

diff --git a/extras/autowaf.py b/extras/autowaf.py
index 51077d1..d779967 100644
--- a/extras/autowaf.py
+++ b/extras/autowaf.py
@@ -807,11 +807,15 @@ def show_diff(from_lines, to_lines, from_filename, to_filename):
     import difflib
     import sys
 
+    same = True
     for line in difflib.unified_diff(
             from_lines, to_lines,
             fromfile=os.path.abspath(from_filename),
             tofile=os.path.abspath(to_filename)):
         sys.stderr.write(line)
+        same = False
+
+    return same
 
 def test_file_equals(patha, pathb):
     import filecmp
@@ -827,9 +831,7 @@ def test_file_equals(patha, pathb):
 
     with io.open(patha, 'rU', encoding='utf-8') as fa:
         with io.open(pathb, 'rU', encoding='utf-8') as fb:
-            show_diff(fa.readlines(), fb.readlines(), patha, pathb)
-
-    return False
+            return show_diff(fa.readlines(), fb.readlines(), patha, pathb)
 
 def bench_time():
     if hasattr(time, 'perf_counter'): # Added in Python 3.3
@@ -888,9 +890,10 @@ class TestScope:
         if 'stderr' in kwargs and kwargs['stderr'] == NONEMPTY:
             # Run with a temp file for stderr and check that it is non-empty
             import tempfile
-            with tempfile.TemporaryFile(mode='w') as stderr:
+            with tempfile.TemporaryFile() as stderr:
                 kwargs['stderr'] = stderr
                 output = self.run(test, **kwargs)
+                stderr.seek(0, 2) # Seek to end
                 return (output if not output else
                         self.run(
                             lambda: stderr.tell() > 0,