Short circuit faster when no tool results are available (#483)

Author: drdavella

src/codemodder/codemods/base_codemod.py

@@ -162,6 +162,10 @@ def _apply(
             else None
         )
 
+        if results is not None and not results:
+            logger.debug("No results for %s", self.id)
+            return
+
         files_to_analyze = (
             [
                 path
@@ -222,6 +226,7 @@ def _process_file(
                 findings_for_rule.extend(
                     results.results_for_rule_and_file(context, rule, filename)
                 )
+            logger.debug("%d findings for %s", len(findings_for_rule), filename)
 
         file_context = FileContext(
             context.directory,
@@ -230,6 +235,9 @@ def _process_file(
             line_include,
             findings_for_rule,
         )
+        if results is not None and not findings_for_rule:
+            logger.debug("no findings for %s, short-circuiting analysis", filename)
+            return file_context
 
         # TODO: for SAST tools we should preemtively filter out files that are not part of the result set
 

tests/test_codemodder.py

@@ -106,21 +106,24 @@ def test_cst_parsing_fails(self, build_report, mock_parse, dir_structure):
 
         build_report.return_value.write_report.assert_called_once()
 
-    @mock.patch("codemodder.codemods.libcst_transformer.update_code")
-    @mock.patch(
-        "codemodder.codemods.libcst_transformer.LibcstTransformerPipeline.apply",
-        new_callable=mock.PropertyMock,
-    )
-    @mock.patch("codemodder.context.CodemodExecutionContext.compile_results")
-    def test_dry_run(self, _, transform_apply, mock_update_code, dir_structure):
+    def test_dry_run(self, mocker, dir_structure):
+        mock_update_code = mocker.patch(
+            "codemodder.codemods.libcst_transformer.update_code"
+        )
+        transform_apply = mocker.patch(
+            "codemodder.codemods.libcst_transformer.LibcstTransformerPipeline.apply",
+            new_callable=mock.PropertyMock,
+        )
+        mocker.patch("codemodder.context.CodemodExecutionContext.compile_results")
+
         code_dir, codetf = dir_structure
         args = [
             str(code_dir),
             "--output",
             str(codetf),
             "--dry-run",
             # Make this test faster by restricting the number of codemods
-            "--codemod-include=url-sandbox",
+            "--codemod-include=use-defusedxml",
         ]
 
         assert not codetf.exists()
@@ -157,7 +160,9 @@ def test_reporting(self, mock_reporting, dry_run, dir_structure):
 
         mock_reporting.return_value.write_report.assert_called_once()
 
-    @pytest.mark.parametrize("codemod", ["secure-random", "pixee:python/secure-random"])
+    @pytest.mark.parametrize(
+        "codemod", ["use-defusedxml", "pixee:python/use-defusedxml"]
+    )
     @mock.patch(
         "codemodder.codemods.libcst_transformer.LibcstTransformerPipeline.apply",
         new_callable=mock.PropertyMock,