Fix a gnarly regression when comparing directories against non-directories....

Fix a gnarly regression when comparing directories against non-directories. (Closes: #292)

diffoscope/comparators/utils/compare.py

@@ -82,9 +82,11 @@ def compare_root_paths(path1, path2):
     # DESCRIPTION attributes either, as the specialize() call above may not
     # have returned a specific instance.
     if difference is None and str(type(file1)) != str(type(file2)):
-        difference = Difference(file1.name, file2.name)
-        difference.add_comment(
-            "Types of files differ; human-readable metadata may match literal file contents."
+        return Difference.from_text(
+            "type: {}".format(file1.file_type),
+            "type: {}".format(file2.file_type),
+            file1.name,
+            file2.name,
         )
 
     return difference
@@ -136,6 +138,11 @@ def compare_files(file1, file2, source=None, diff_content_only=False):
     ):
         return file1.compare_bytes(file2, source)
     with profile("compare_files (cumulative)", file1):
+        if file2.is_directory():
+            difference = file2.compare(file1, source)
+            if difference is not None:
+                difference = difference.get_reverse()
+            return difference
         return file1.compare(file2, source)
 
 

tests/comparators/test_directory.py

@@ -23,6 +23,7 @@ import pytest
 
 from diffoscope.comparators.binary import FilesystemFile
 from diffoscope.comparators.directory import compare_directories
+from diffoscope.comparators.utils.compare import compare_root_paths
 from diffoscope.comparators.utils.specialize import specialize
 
 from ..utils.data import data, get_data, assert_diff
@@ -113,14 +114,14 @@ def test_compare_to_dangling_symlink(tmpdir):
     assert_diff(a.compare(b), "test_directory_symlink_diff")
 
 
-@pytest.mark.xfail(strict=False)
 def test_compare_both_ways(tmpdir):
     """
     Comparing a directory with a file shouldn't crash, but nor should as
     comparing a file with a directory either. (Re: #292)
     """
 
-    a = specialize(FilesystemFile(str(tmpdir)))
-    b = specialize(FilesystemFile(TEST_FILE1_PATH))
-    a.compare(b)
-    b.compare(a)
+    a = str(tmpdir)
+    b = TEST_FILE1_PATH
+
+    assert_diff(compare_root_paths(a, b), "test_directory_a_b_diff")
+    assert_diff(compare_root_paths(b, a), "test_directory_b_a_diff")

tests/data/test_directory_a_b_diff

+@@ -1 +1 @@
+-type: directory
++type: file

tests/data/test_directory_b_a_diff

+@@ -1 +1 @@
++type: directory
+-type: file