# HG changeset patch
# User steve@McMurphy
# Date 1399332359 25200
# Node ID ad50edf7a54e7a113ab4142e5d952f47187f0ed5
# Parent  3aa5fae8c31318101a5c07565c288fb6d42c6a1e
use clearer "shallow" comparion semantics in filecmp.cmp

diff -r 3aa5fae8c313 -r ad50edf7a54e Doc/library/filecmp.rst
--- a/Doc/library/filecmp.rst	Sun May 04 04:45:57 2014 -0700
+++ b/Doc/library/filecmp.rst	Mon May 05 16:25:59 2014 -0700
@@ -21,8 +21,8 @@
    Compare the files named *f1* and *f2*, returning ``True`` if they seem equal,
    ``False`` otherwise.
 
-   If *shallow* is true, files with identical :func:`os.stat` signatures are
-   taken to be equal.  Otherwise, the contents of the files are compared.
+   If *shallow* is true, only the files' :func:`os.stat` signatures are
+   compared.  If *shallow* is false, the contents of the files are compared.
 
    Note that no external programs are called from this function, giving it
    portability and efficiency.
diff -r 3aa5fae8c313 -r ad50edf7a54e Lib/filecmp.py
--- a/Lib/filecmp.py	Sun May 04 04:45:57 2014 -0700
+++ b/Lib/filecmp.py	Mon May 05 16:25:59 2014 -0700
@@ -52,8 +52,8 @@
     s2 = _sig(os.stat(f2))
     if s1[0] != stat.S_IFREG or s2[0] != stat.S_IFREG:
         return False
-    if shallow and s1 == s2:
-        return True
+    if shallow:
+        return s1 == s2
     if s1[1] != s2[1]:
         return False
 
diff -r 3aa5fae8c313 -r ad50edf7a54e Lib/test/test_filecmp.py
--- a/Lib/test/test_filecmp.py	Sun May 04 04:45:57 2014 -0700
+++ b/Lib/test/test_filecmp.py	Mon May 05 16:25:59 2014 -0700
@@ -12,19 +12,32 @@
         self.name = support.TESTFN
         self.name_same = support.TESTFN + '-same'
         self.name_diff = support.TESTFN + '-diff'
+        self.name_same_diffsig = support.TESTFN + '-same-diffsig'
+        self.name_diff_samesig = support.TESTFN + '-diff-samesig'
         data = 'Contents of file go here.\n'
-        for name in [self.name, self.name_same, self.name_diff]:
+        for name in [self.name, self.name_same, self.name_diff,
+                     self.name_same_diffsig]:
             with open(name, 'w') as output:
                 output.write(data)
 
         with open(self.name_diff, 'a+') as output:
             output.write('An extra line.\n')
+
+        with open(self.name_diff_samesig, 'w') as output:
+            output.write(data.upper())
+
+        st = os.stat(self.name)
+        os.utime(self.name_same_diffsig, (st.st_atime, st.st_mtime - 24*60*60))
+        os.utime(self.name_diff_samesig, (st.st_atime, st.st_mtime))
+        
         self.dir = tempfile.gettempdir()
 
     def tearDown(self):
         os.unlink(self.name)
         os.unlink(self.name_same)
         os.unlink(self.name_diff)
+        os.unlink(self.name_same_diffsig)
+        os.unlink(self.name_diff_samesig)
 
     def test_matching(self):
         self.assertTrue(filecmp.cmp(self.name, self.name_same),
@@ -49,6 +62,22 @@
         self.assertTrue(len(filecmp._cache) == 0,
                         "Cache not cleared after calling clear_cache")
 
+    def test_shallow_false_negative(self):
+        self.assertFalse(filecmp.cmp(self.name, self.name_same_diffsig),
+                         "Shallow comparison not done by file signature")
+
+    def test_shallow_false_positive(self):
+        self.assertTrue(filecmp.cmp(self.name, self.name_diff_samesig),
+                        "Shallow comparison not done by file signature")
+
+    def test_deep_comparisons(self):
+        self.assertTrue(filecmp.cmp(self.name, self.name_same_diffsig,
+                                    shallow=False),
+                        "Deep comparison not done by file contents")
+        self.assertFalse(filecmp.cmp(self.name, self.name_diff_samesig,
+                                     shallow=False),
+                         "Deep comparison not done by file contents")
+
 class DirCompareTestCase(unittest.TestCase):
     def setUp(self):
         tmpdir = tempfile.gettempdir()