Add back --report-deprecated-as-note to change error to note

Author: svalentin

docs/source/command_line.rst

@@ -537,6 +537,12 @@ potentially problematic or redundant in some way.
 
         This limitation will be removed in future releases of mypy.
 
+.. option:: --report-deprecated-as-note
+
+    If error code ``deprecated`` is enabled, mypy emits errors if your code
+    imports or uses deprecated features. This flag converts such errors to
+    notes, causing mypy to eventually finish with a zero exit code. Features
+    are considered deprecated when decorated with ``warnings.deprecated``.
 
 .. _miscellaneous-strictness-flags:
 

docs/source/error_code_list2.rst

@@ -240,8 +240,9 @@ If you use :option:`--enable-error-code deprecated <mypy --enable-error-code>`,
 mypy generates an error if your code imports a deprecated feature explicitly with a
 ``from mod import depr`` statement or uses a deprecated feature imported otherwise or defined
 locally.  Features are considered deprecated when decorated with ``warnings.deprecated``, as
-specified in `PEP 702 <https://peps.python.org/pep-0702>`_.  You can silence single errors via
-``# type: ignore[deprecated]`` or turn off this check completely via ``--disable-error-code=deprecated``.
+specified in `PEP 702 <https://peps.python.org/pep-0702>`_.
+Use the :option:`--report-deprecated-as-note <mypy --report-deprecated-as-note>` option to
+turn all such errors into notes.
 
 .. note::
 

mypy/checker.py

@@ -7696,8 +7696,8 @@ def warn_deprecated(self, node: SymbolNode | None, context: Context) -> None:
             and ((deprecated := node.deprecated) is not None)
             and not self.is_typeshed_stub
         ):
-            self.msg.fail(deprecated, context, code=codes.DEPRECATED)
-
+            warn = self.msg.note if self.options.report_deprecated_as_note else self.msg.fail
+            warn(deprecated, context, code=codes.DEPRECATED)
 
 class CollectArgTypeVarTypes(TypeTraverserVisitor):
     """Collects the non-nested argument types in a set."""

mypy/errors.py

@@ -20,7 +20,7 @@
 
 # Show error codes for some note-level messages (these usually appear alone
 # and not as a comment for a previous error-level message).
-SHOW_NOTE_CODES: Final = {codes.ANNOTATION_UNCHECKED}
+SHOW_NOTE_CODES: Final = {codes.ANNOTATION_UNCHECKED, codes.DEPRECATED}
 
 # Do not add notes with links to error code docs to errors with these codes.
 # We can tweak this set as we get more experience about what is helpful and what is not.

mypy/main.py

@@ -804,6 +804,13 @@ def add_invertible_flag(
         help="Warn about statements or expressions inferred to be unreachable",
         group=lint_group,
     )
+    add_invertible_flag(
+        "--report-deprecated-as-note",
+        default=False,
+        strict_flag=False,
+        help="Report importing or using deprecated features as notes instead of errors",
+        group=lint_group,
+    )
 
     # Note: this group is intentionally added here even though we don't add
     # --strict to this group near the end.

mypy/options.py

@@ -173,6 +173,9 @@ def __init__(self) -> None:
         # declared with a precise type
         self.warn_return_any = False
 
+        # Report importing or using deprecated features as errors instead of notes.
+        self.report_deprecated_as_note = False
+
         # Warn about unused '# type: ignore' comments
         self.warn_unused_ignores = False
 

mypy/typeanal.py

@@ -790,7 +790,8 @@ def check_and_warn_deprecated(self, info: TypeInfo, ctx: Context) -> None:
                 if isinstance(imp, ImportFrom) and any(info.name == n[0] for n in imp.names):
                     break
             else:
-                self.fail(deprecated, ctx, code=codes.DEPRECATED)
+                warn = self.note if self.options.report_deprecated_as_note else self.fail
+                warn(deprecated, ctx, code=codes.DEPRECATED)
 
     def analyze_type_with_type_info(
         self, info: TypeInfo, args: Sequence[Type], ctx: Context, empty_tuple_index: bool

test-data/unit/check-deprecated.test

@@ -1,7 +1,7 @@
 -- Type checker test cases for reporting deprecations.
 
 
-[case testDeprecatedDisableNotes]
+[case testDeprecatedDisabled]
 
 from typing_extensions import deprecated
 
@@ -13,6 +13,20 @@ f()
 [builtins fixtures/tuple.pyi]
 
 
+[case testDeprecatedAsNoteWithErrorCode]
+# flags: --enable-error-code=deprecated --show-error-codes --report-deprecated-as-note
+
+from typing_extensions import deprecated
+
+@deprecated("use f2 instead")
+def f() -> None: ...
+
+f() # type: ignore[deprecated]
+f() # N: function __main__.f is deprecated: use f2 instead  [deprecated]
+
+[builtins fixtures/tuple.pyi]
+
+
 [case testDeprecatedAsErrorWithErrorCode]
 # flags: --enable-error-code=deprecated --show-error-codes