Fix pip-compile package ordering

piptools/writer.py

@@ -89,7 +89,7 @@ def __init__(
         self.emit_find_links = emit_find_links
 
     def _sort_key(self, ireq: InstallRequirement) -> Tuple[bool, str]:
-        return (not ireq.editable, str(ireq.req).lower())
+        return (not ireq.editable, key_from_ireq(ireq))
 
     def write_header(self) -> Iterator[str]:
         if self.emit_header:

tests/test_cli_compile.py

@@ -827,10 +827,10 @@ def test_generate_hashes_with_annotations(runner):
 @pytest.mark.network
 def test_generate_hashes_with_long_annotations(runner):
     with open("requirements.in", "w") as fp:
+        fp.write("Django==1.11.29\n")
         fp.write("django-debug-toolbar==1.11\n")
         fp.write("django-storages==1.9.1\n")
         fp.write("django-taggit==0.24.0\n")
-        fp.write("Django==1.11.29\n")
         fp.write("pytz==2020.4\n")
         fp.write("sqlparse==0.3.1\n")
 
@@ -844,6 +844,14 @@ def test_generate_hashes_with_long_annotations(runner):
         #
         #    pip-compile --generate-hashes
         #
+        django==1.11.29 \\
+            --hash=sha256:014e3392058d94f40569206a24523ce254d55ad2f9f46c6550b0fe2e4f94cf3f \\
+            --hash=sha256:4200aefb6678019a0acf0005cd14cfce3a5e6b9b90d06145fcdd2e474ad4329c
+            # via
+            #   -r requirements.in
+            #   django-debug-toolbar
+            #   django-storages
+            #   django-taggit
         django-debug-toolbar==1.11 \\
             --hash=sha256:89d75b60c65db363fb24688d977e5fbf0e73386c67acf562d278402a10fc3736 \\
             --hash=sha256:c2b0134119a624f4ac9398b44f8e28a01c7686ac350a12a74793f3dd57a9eea0
@@ -856,14 +864,6 @@ def test_generate_hashes_with_long_annotations(runner):
             --hash=sha256:710b4d15ec1996550cc68a0abbc41903ca7d832540e52b1336e6858737e410d8 \\
             --hash=sha256:bb8f27684814cd1414b2af75b857b5e26a40912631904038a7ecacd2bfafc3ac
             # via -r requirements.in
-        django==1.11.29 \\
-            --hash=sha256:014e3392058d94f40569206a24523ce254d55ad2f9f46c6550b0fe2e4f94cf3f \\
-            --hash=sha256:4200aefb6678019a0acf0005cd14cfce3a5e6b9b90d06145fcdd2e474ad4329c
-            # via
-            #   -r requirements.in
-            #   django-debug-toolbar
-            #   django-storages
-            #   django-taggit
         pytz==2020.4 \\
             --hash=sha256:3e6b7dd2d1e0a59084bcee14a17af60c5c562cdc16d828e8eba2e683d3a7e268 \\
             --hash=sha256:5c55e189b682d420be27c6995ba6edce0c0a77dd67bfbe2ae6607134d5851ffd

tests/test_writer.py

@@ -344,3 +344,24 @@ def test_write_find_links(writer, find_links, expected_lines):
     """
     writer.find_links = find_links
     assert list(writer.write_find_links()) == expected_lines
+
+
+def test_write_order(writer, from_line):
+    """
+    Order of packages should match that of `pip freeze`.
+    """
+    writer.emit_header = False
+
+    packages = [
+        from_line("package_a==0.1"),
+        from_line("Package-b==2.3.4"),
+        from_line("Package==5.6"),
+        from_line("package2==7.8.9"),
+    ]
+    expected_lines = [
+        "package==5.6",
+        "package_a==0.1",
+        "package-b==2.3.4",
+        "package2==7.8.9",
+    ]
+    assert list(writer._iter_lines(packages)) == expected_lines