baseline: show baselined errors as notes (baseline-as-notes)

Author: KotlinIsland

mypy/build.py

@@ -3386,7 +3386,7 @@ def process_stale_scc(graph: Graph, scc: List[str], manager: BuildManager) -> No
         for id in stale:
             graph[id].transitive_error = True
     for id in stale:
-        manager.errors.filter_baseline(graph[id].xpath)
+        manager.errors.filter_baseline(graph[id].xpath, manager.options.baseline_as_notes)
         # show new errors only
         manager.flush_errors(
             manager.errors.file_messages(graph[id].xpath),

mypy/errors.py

@@ -977,7 +977,7 @@ def prepare_baseline_errors(self, baseline_format: str) -> Dict[
                     del error["line"]
         return result
 
-    def filter_baseline(self, path: str) -> None:
+    def filter_baseline(self, path: str, as_notes: bool) -> None:
         """Remove baseline errors from the error_info_map"""
         if path not in self.error_info_map:
             return
@@ -1001,8 +1001,12 @@ def filter_baseline(self, path: str) -> None:
                         clean_baseline_message(error.message) ==
                         clean_baseline_message(baseline_error["message"])
                 ):
-                    ignored_notes.extend([id(note) for note in error.notes])
                     del baseline_errors[i]
+                    if as_notes:
+                        new_errors.append(error)
+                        error.severity = "note"
+                    else:
+                        ignored_notes.extend([id(note) for note in error.notes])
                     break
             else:
                 new_errors.append(error)
@@ -1023,8 +1027,12 @@ def filter_baseline(self, path: str) -> None:
                         clean_baseline_message(baseline_error["message"]) and
                         abs(error.line - baseline_error["line"]) < 100
                 ):
-                    ignored_notes.extend([id(note) for note in error.notes])
                     del baseline_errors[i]
+                    if as_notes:
+                        error.severity = "note"
+                        new_errors.append(error)
+                    else:
+                        ignored_notes.extend([id(note) for note in error.notes])
                     break
             else:
                 new_errors.append(error)

mypy/main.py

@@ -538,6 +538,9 @@ def add_invertible_flag(flag: str,
     add_invertible_flag(
         '--no-auto-baseline', default=True, group=based_group,
         dest="auto_baseline", help="Don't update the baseline automatically.")
+    add_invertible_flag(
+        '--baseline-as-notes', group=based_group, default=False,
+        help="Output the baselined errors as notes (useful for IDEs).")
     based_group.add_argument(
         '--legacy', action='store_true',
         help="Disable all based functionality")

mypy/options.py

@@ -130,6 +130,7 @@ def __init__(self) -> None:
         self.targets: List[str] = []
         self.ignore_any_from_error = True
         self.incomplete_is_typed = flip_if_not_based(False)
+        self.baseline_as_notes = False
 
         # disallow_any options
         self.disallow_any_generics = flip_if_not_based(True)