bpo-30177: pathlib: include the full path in resolve(strict=False) (#1893)

Lib/pathlib.py

@@ -183,19 +183,18 @@ class _WindowsFlavour(_Flavour):
             if strict:
                 return self._ext_to_normal(_getfinalpathname(s))
             else:
+                tail_parts = []  # End of the path after the first one not found
                 while True:
                     try:
                         s = self._ext_to_normal(_getfinalpathname(s))
                     except FileNotFoundError:
                         previous_s = s
-                        s = os.path.dirname(s)
+                        s, tail = os.path.split(s)
+                        tail_parts.append(tail)
                         if previous_s == s:
                             return path
                     else:
-                        if previous_s is None:
-                            return s
-                        else:
-                            return s + os.path.sep + os.path.basename(previous_s)
+                        return os.path.join(s, *reversed(tail_parts))
         # Means fallback on absolute
         return None
 
@@ -326,12 +325,10 @@ class _PosixFlavour(_Flavour):
                 try:
                     target = accessor.readlink(newpath)
                 except OSError as e:
-                    if e.errno != EINVAL:
-                        if strict:
-                            raise
-                        else:
-                            return newpath
-                    # Not a symlink
+                    if e.errno != EINVAL and strict:
+                        raise
+                    # Not a symlink, or non-strict mode. We just leave the path
+                    # untouched.
                     path = newpath
                 else:
                     seen[newpath] = None # not resolved symlink

Lib/test/test_pathlib.py

@@ -1492,10 +1492,10 @@ class _BasePathTest(object):
                          os.path.join(BASE, 'foo'))
         p = P(BASE, 'foo', 'in', 'spam')
         self.assertEqual(str(p.resolve(strict=False)),
-                         os.path.join(BASE, 'foo'))
+                         os.path.join(BASE, 'foo', 'in', 'spam'))
         p = P(BASE, '..', 'foo', 'in', 'spam')
         self.assertEqual(str(p.resolve(strict=False)),
-                         os.path.abspath(os.path.join('foo')))
+                         os.path.abspath(os.path.join('foo', 'in', 'spam')))
         # These are all relative symlinks
         p = P(BASE, 'dirB', 'fileB')
         self._check_resolve_relative(p, p)
@@ -1507,16 +1507,18 @@ class _BasePathTest(object):
         self._check_resolve_relative(p, P(BASE, 'dirB', 'fileB'))
         # Non-strict
         p = P(BASE, 'dirA', 'linkC', 'fileB', 'foo', 'in', 'spam')
-        self._check_resolve_relative(p, P(BASE, 'dirB', 'fileB', 'foo'), False)
+        self._check_resolve_relative(p, P(BASE, 'dirB', 'fileB', 'foo', 'in',
+                                          'spam'), False)
         p = P(BASE, 'dirA', 'linkC', '..', 'foo', 'in', 'spam')
         if os.name == 'nt':
             # In Windows, if linkY points to dirB, 'dirA\linkY\..'
             # resolves to 'dirA' without resolving linkY first.
-            self._check_resolve_relative(p, P(BASE, 'dirA', 'foo'), False)
+            self._check_resolve_relative(p, P(BASE, 'dirA', 'foo', 'in',
+                                              'spam'), False)
         else:
             # In Posix, if linkY points to dirB, 'dirA/linkY/..'
             # resolves to 'dirB/..' first before resolving to parent of dirB.
-            self._check_resolve_relative(p, P(BASE, 'foo'), False)
+            self._check_resolve_relative(p, P(BASE, 'foo', 'in', 'spam'), False)
         # Now create absolute symlinks
         d = tempfile.mkdtemp(suffix='-dirD')
         self.addCleanup(support.rmtree, d)
@@ -1526,16 +1528,17 @@ class _BasePathTest(object):
         self._check_resolve_absolute(p, P(BASE, 'dirB', 'fileB'))
         # Non-strict
         p = P(BASE, 'dirA', 'linkX', 'linkY', 'foo', 'in', 'spam')
-        self._check_resolve_relative(p, P(BASE, 'dirB', 'foo'), False)
+        self._check_resolve_relative(p, P(BASE, 'dirB', 'foo', 'in', 'spam'),
+                                     False)
         p = P(BASE, 'dirA', 'linkX', 'linkY', '..', 'foo', 'in', 'spam')
         if os.name == 'nt':
             # In Windows, if linkY points to dirB, 'dirA\linkY\..'
             # resolves to 'dirA' without resolving linkY first.
-            self._check_resolve_relative(p, P(d, 'foo'), False)
+            self._check_resolve_relative(p, P(d, 'foo', 'in', 'spam'), False)
         else:
             # In Posix, if linkY points to dirB, 'dirA/linkY/..'
             # resolves to 'dirB/..' first before resolving to parent of dirB.
-            self._check_resolve_relative(p, P(BASE, 'foo'), False)
+            self._check_resolve_relative(p, P(BASE, 'foo', 'in', 'spam'), False)
 
     @support.skip_unless_symlink
     def test_resolve_dot(self):
@@ -1549,7 +1552,7 @@ class _BasePathTest(object):
         r = q / '3' / '4'
         self.assertRaises(FileNotFoundError, r.resolve, strict=True)
         # Non-strict
-        self.assertEqual(r.resolve(strict=False), p / '3')
+        self.assertEqual(r.resolve(strict=False), p / '3' / '4')
 
     def test_with(self):
         p = self.cls(BASE)

Misc/ACKS

@@ -1201,6 +1201,7 @@ Steve Piercy
 Jim St. Pierre
 Dan Pierson
 Martijn Pieters
+Antoine Pietri
 Anand B. Pillai
 François Pinard
 Tom Pinckney