fix: Fix caching the issues with fixes (#1623)

Author: bhirsz

src/robocop/linter/runner.py

@@ -13,7 +13,6 @@
 from robocop.linter.diagnostics import Diagnostics, RunStatistic
 from robocop.linter.fix import FixApplier
 from robocop.linter.reports import save_reports_result_to_cache
-from robocop.linter.rules import FixableRule
 from robocop.linter.utils.disablers import DisablersFinder
 from robocop.linter.utils.file_types import get_resource_with_lang
 from robocop.linter.utils.misc import is_suite_templated
@@ -105,8 +104,8 @@ def run(self) -> list[Diagnostic]:
                 print(f"Scanning file: {source_file.path}")
             diagnostics = self.get_cached_diagnostics(source_file.config, source_file.path)
             if diagnostics is not None:
-                fixes = [diag.fix(source_file) for diag in diagnostics if isinstance(diag.rule, FixableRule)]
-                if not fix_applier.apply_fixes(source_file, fixes):
+                no_fixables = all(not diag.rule.fixable for diag in diagnostics)
+                if no_fixables or not (source_file.config.linter.fix or source_file.config.linter.diff):
                     self.diagnostics.extend(diagnostics)
                     files += 1
                     cached_files += 1
@@ -116,7 +115,8 @@ def run(self) -> list[Diagnostic]:
                 continue
             self.diagnostics.extend(diagnostics)
             files += 1
-            self.config_manager.cache.set_linter_entry(source_file.path, source_file.config.hash(), diagnostics)
+            if not source_file.config.linter.diff:  # diff simulate fixes, so it's best to ignore the results
+                self.config_manager.cache.set_linter_entry(source_file.path, source_file.config.hash(), diagnostics)
         self.config_manager.cache.save()
 
         if not files and not self.config_manager.default_config.silent:

tests/cache/test_cache_integration.py

@@ -5,6 +5,7 @@
 import shutil
 import time
 from pathlib import Path
+from textwrap import dedent
 
 import msgpack
 
@@ -244,6 +245,66 @@ def test_cache_with_multiple_files(self, tmp_path, capsys):
             assert "Used cached results for 1 of 2 files" in out2
             assert len(second_result) == first_count  # Results unchanged (just added comment)
 
+    def test_cache_with_fixable_rule(self, tmp_path, capsys):
+        """Test cache behavior with fixable rules."""
+        # Arrange - create tedt file for fixable rule
+        test_file = tmp_path / "test.robot"
+        content = dedent("""
+        *** Settings ***
+        Suite Setup    With Trailing Whitespace    
+        """).lstrip()  # noqa: W291
+        test_file.write_text(content, encoding="utf-8")
+
+        with working_directory(tmp_path):
+            # Act - first run to populate cache
+            result1 = check_files(return_result=True, verbose=True)
+            out1, _ = capsys.readouterr()
+            # Act - second run to regain fixable rules
+            result2 = check_files(return_result=True, verbose=True)
+            out2, _ = capsys.readouterr()
+            # Act - third run that shows fix diff
+            result3 = check_files(return_result=True, verbose=True, diff=True)
+            out3, _ = capsys.readouterr()
+            # Act - fourth run that has all issues (diff does not change it)
+            result4 = check_files(return_result=True, verbose=True)
+            out4, _ = capsys.readouterr()
+            # Act - fifth run that fixes the issue
+            result5 = check_files(return_result=True, verbose=True, fix=True)
+            out5, _ = capsys.readouterr()
+            # Act - sixth run that has only remaining issues
+            result6 = check_files(return_result=True, verbose=True)
+            out6, _ = capsys.readouterr()
+
+            # Assert - first run not yet cached, all issues
+            assert "Used cached results" not in out1
+            assert len(result1) == 3
+            assert "1 fixable with the ``--fix`` option." in out1
+
+            # Assert - second run cached, all issues
+            assert "Used cached results" in out2
+            assert len(result2) == 3
+            assert "1 fixable with the ``--fix`` option." in out2
+
+            # Assert - third run not cached, only unfixable issues in results (fixable goes to diff)
+            assert "Used cached results" not in out3  # we didn't use cache since we generated diff
+            assert len(result3) == 2
+            assert "Found 3 issues (1 fixed, 2 remaining)." in out3  # it is printed but not applied (diff)
+
+            # Assert - fourth run cached, all issues (no changes from diff)
+            assert "Used cached results" in out4
+            assert len(result4) == 3
+            assert "1 fixable with the ``--fix`` option." in out4
+
+            # Assert - fifth run not cached, only unfixable issues in results (fixable are fixed)
+            assert "Used cached results" not in out5
+            assert len(result5) == 2
+            assert "Found 3 issues (1 fixed, 2 remaining)." in out5
+
+            # Assert - sixth run cached, only unfixable issues (fixable were fixed)
+            assert "Used cached results" in out6
+            assert len(result6) == 2
+            assert "Found 2 issues." in out6
+
     def test_file_with_parse_error_not_cached(self, tmp_path, capsys):
         """Test that files with parse errors are not cached."""
         # Arrange - create file with actual encoding/binary issues that cause DataError