Widen mathutils param types, fix getset_descriptor writability, add conformance tests

- Widen bare mathutils type params (Vector, Euler, etc.) to also accept
  Sequence[float], matching Blender's mathutils_array_parse C behavior
- Fix getset_descriptor readonly detection by probing __set__ on the
  descriptor instead of checking fset (which doesn't exist on C descriptors)
- Accept int | slice keys in __getitem__/__setitem__/__delitem__
- Accept Sequence[element_type] values in __setitem__ for slice assignment
- Add mathutils overrides for Matrix.Translation and Matrix.Scale
- Extend apply_overrides to support ClassName.method_name keys
- Add conformance test files from Blender docs examples
- Disable reportUnusedExpression in conformance checks

Remaining known conformance issues:
- draw_handler_add missing from SpaceView3D
- Vector not nominally Sequence[float] (buffer protocol, swizzle setters)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

conformance/test_gpu_3d_points_with_single_color.py

@@ -0,0 +1,37 @@
+import bpy
+import gpu
+from gpu_extras.batch import batch_for_shader
+
+coords = [(1, 1, 1), (-2, 0, 0), (-2, -1, 3), (0, 1, 1)]
+shader = gpu.shader.from_builtin("POINT_UNIFORM_COLOR")
+batch = batch_for_shader(shader, "POINTS", {"pos": coords})
+
+
+def draw():
+    shader.uniform_float("color", (1, 1, 0, 1))
+    gpu.state.point_size_set(4.5)
+    batch.draw(shader)
+
+
+bpy.types.SpaceView3D.draw_handler_add(draw, (), "WINDOW", "POST_VIEW")
+
+
+"""
+
+3D Lines with Single Color
+--------------------------
+"""
+
+coords = [(1, 1, 1), (-2, 0, 0), (-2, -1, 3), (0, 1, 1)]
+shader = gpu.shader.from_builtin("POLYLINE_UNIFORM_COLOR")
+batch = batch_for_shader(shader, "LINES", {"pos": coords})
+
+
+def draw():
+    shader.uniform_float("viewportSize", gpu.state.viewport_get()[2:])
+    shader.uniform_float("lineWidth", 4.5)
+    shader.uniform_float("color", (1, 1, 0, 1))
+    batch.draw(shader)
+
+
+bpy.types.SpaceView3D.draw_handler_add(draw, (), "WINDOW", "POST_VIEW")

conformance/test_gpu_triangle_with_custom_shader.py

@@ -0,0 +1,42 @@
+import bpy
+import gpu
+from gpu_extras.batch import batch_for_shader
+
+vert_out = gpu.types.GPUStageInterfaceInfo("my_interface")
+vert_out.smooth("VEC3", "pos")
+
+shader_info = gpu.types.GPUShaderCreateInfo()
+shader_info.push_constant("MAT4", "viewProjectionMatrix")
+shader_info.push_constant("FLOAT", "brightness")
+shader_info.vertex_in(0, "VEC3", "position")
+shader_info.vertex_out(vert_out)
+shader_info.fragment_out(0, "VEC4", "FragColor")
+
+shader_info.vertex_source(
+    "void main()"
+    "{"
+    "  pos = position;"
+    "  gl_Position = viewProjectionMatrix * vec4(position, 1.0f);"
+    "}"
+)
+
+shader_info.fragment_source(
+    "void main()" "{" "  FragColor = vec4(pos * brightness, 1.0);" "}"
+)
+
+shader = gpu.shader.create_from_info(shader_info)
+del vert_out
+del shader_info
+
+coords = [(1, 1, 1), (2, 0, 0), (-2, -1, 3)]
+batch = batch_for_shader(shader, "TRIS", {"position": coords})
+
+
+def draw():
+    matrix = bpy.context.region_data.perspective_matrix
+    shader.uniform_float("viewProjectionMatrix", matrix)
+    shader.uniform_float("brightness", 0.5)
+    batch.draw(shader)
+
+
+bpy.types.SpaceView3D.draw_handler_add(draw, (), "WINDOW", "POST_VIEW")

conformance/test_mathutils_color.py

@@ -0,0 +1,37 @@
+import mathutils
+
+# Color values are represented as RGB values from 0 - 1, this is blue.
+col = mathutils.Color((0.0, 0.0, 1.0))
+
+# As well as r/g/b attribute access you can adjust them by h/s/v.
+col.s *= 0.5
+
+# You can access its components by attribute or index.
+print("Color R:", col.r)
+print("Color G:", col[1])
+print("Color B:", col[-1])
+print("Color HSV: {:.2f}, {:.2f}, {:.2f}".format(*col))
+
+
+# Components of an existing color can be set.
+col[:] = 0.0, 0.5, 1.0
+
+# Components of an existing color can use slice notation to get a tuple.
+print("Values: {:f}, {:f}, {:f}".format(*col))
+
+# Colors can be added and subtracted.
+col += mathutils.Color((0.25, 0.0, 0.0))
+
+# Color can be multiplied, in this example color is scaled to 0-255
+# can printed as integers.
+print("Color: {:d}, {:d}, {:d}".format(*(int(c) for c in (col * 255.0))))
+
+# This example prints the color as hexadecimal.
+print(
+    "Hexadecimal: {:02x}{:02x}{:02x}".format(
+        int(col.r * 255), int(col.g * 255), int(col.b * 255)
+    )
+)
+
+# Direct buffer access is supported at runtime via C buffer protocol
+# but not expressible in type stubs (requires Python 3.12+ __buffer__).

conformance/test_mathutils_matrix.py

@@ -0,0 +1,35 @@
+import mathutils
+import math
+
+# Create a location matrix.
+mat_loc = mathutils.Matrix.Translation((2.0, 3.0, 4.0))
+
+# Create an identity matrix.
+mat_sca = mathutils.Matrix.Scale(0.5, 4, (0.0, 0.0, 1.0))
+
+# Create a rotation matrix.
+mat_rot = mathutils.Matrix.Rotation(math.radians(45.0), 4, "X")
+
+# Combine transformations.
+mat_out = mat_loc @ mat_rot @ mat_sca
+print(mat_out)
+
+# Extract components back out of the matrix as two vectors and a quaternion.
+loc, rot, sca = mat_out.decompose()
+print(loc, rot, sca)
+
+# Recombine extracted components.
+mat_out2 = mathutils.Matrix.LocRotScale(loc, rot, sca)
+print(mat_out2)
+
+# It can also be useful to access components of a matrix directly.
+mat = mathutils.Matrix()
+mat[0][0], mat[1][0], mat[2][0] = 0.0, 1.0, 2.0
+
+mat[0][0:3] = 0.0, 1.0, 2.0
+
+# Each item in a matrix is a vector so vector utility functions can be used.
+mat[0].xyz = 0.0, 1.0, 2.0
+
+# Direct buffer access is supported at runtime via C buffer protocol
+# but not expressible in type stubs (requires Python 3.12+ __buffer__).

conformance/test_mathutils_quaternion.py

@@ -0,0 +1,40 @@
+import mathutils
+import math
+
+# A new rotation 90 degrees about the Y axis.
+quat_a = mathutils.Quaternion((0.7071068, 0.0, 0.7071068, 0.0))
+
+# Passing values to Quaternion's directly can be confusing so axis, angle
+# is supported for initializing too.
+quat_b = mathutils.Quaternion((0.0, 1.0, 0.0), math.radians(90.0))
+
+print("Check quaternions match", quat_a == quat_b)
+
+# Like matrices, quaternions can be multiplied to accumulate rotational values.
+quat_a = mathutils.Quaternion((0.0, 1.0, 0.0), math.radians(90.0))
+quat_b = mathutils.Quaternion((0.0, 0.0, 1.0), math.radians(45.0))
+quat_out = quat_a @ quat_b
+
+# Print the quaternion, euler degrees for mere mortals and (axis, angle).
+print("Final Rotation:")
+print(quat_out)
+print("{:.2f}, {:.2f}, {:.2f}".format(*(math.degrees(a) for a in quat_out.to_euler())))
+print(
+    "({:.2f}, {:.2f}, {:.2f}), {:.2f}".format(
+        *quat_out.axis, math.degrees(quat_out.angle)
+    )
+)
+
+# Multiple rotations can be interpolated using the exponential map.
+quat_c = mathutils.Quaternion((1.0, 0.0, 0.0), math.radians(15.0))
+exp_avg = (
+    quat_a.to_exponential_map()
+    + quat_b.to_exponential_map()
+    + quat_c.to_exponential_map()
+) / 3.0
+quat_avg = mathutils.Quaternion(exp_avg)
+print("Average rotation:")
+print(quat_avg)
+
+# Direct buffer access is supported.
+print(memoryview(quat_avg).tobytes())

conformance/test_mathutils_vector.py

@@ -0,0 +1,58 @@
+import mathutils
+
+# Zero length vector.
+vec = mathutils.Vector((0.0, 0.0, 1.0))
+
+# Unit length vector.
+vec_a = vec.normalized()
+
+vec_b = mathutils.Vector((0.0, 1.0, 2.0))
+
+vec2d = mathutils.Vector((1.0, 2.0))
+vec3d = mathutils.Vector((1.0, 0.0, 0.0))
+vec4d = vec_a.to_4d()
+
+# Other `mathutils` types.
+quat = mathutils.Quaternion()
+matrix = mathutils.Matrix()
+
+# Comparison operators can be done on Vector classes:
+
+# (In)equality operators == and != test component values, e.g. 1,2,3 != 3,2,1
+vec_a == vec_b
+vec_a != vec_b
+
+# Ordering operators >, >=, > and <= test vector length.
+vec_a > vec_b
+vec_a >= vec_b
+vec_a < vec_b
+vec_a <= vec_b
+
+
+# Math can be performed on Vector classes.
+vec_a + vec_b
+vec_a - vec_b
+vec_a @ vec_b
+vec_a * 10.0
+matrix @ vec_a
+quat @ vec_a
+-vec_a
+
+
+# You can access a vector object like a sequence.
+x = vec_a[0]
+len(vec)
+vec_a[:] = vec_b
+vec_a[:] = 1.0, 2.0, 3.0
+vec2d[:] = vec3d[:2]
+
+
+# Vectors support 'swizzle' operations.
+# See https://en.wikipedia.org/wiki/Swizzling_(computer_graphics)
+vec.xyz = vec.zyx
+vec.xy = vec4d.zw
+vec.xyz = vec4d.wzz
+vec4d.wxyz = vec.yxyx
+
+# Direct buffer access is supported.
+raw_data = memoryview(vec).tobytes()

generate_stubs.py

@@ -760,9 +760,7 @@ def load_overrides(overrides_dir: str, module_name: str) -> dict[str, ParamOverr
     return {}
 
 
-def _apply_func_overrides(
-    func: FunctionData, func_overrides: ParamOverrides
-) -> None:
+def _apply_func_overrides(func: FunctionData, func_overrides: ParamOverrides) -> None:
     """Apply overrides to a single function/method."""
     param_overrides = func_overrides.get("params", {})
     for param in func["params"]:

introspect.py

@@ -226,7 +226,9 @@ def parse_docstring_types(docstring: str) -> tuple[dict[str, str], str | None]:
 
     # Match :type param: ... up to the next RST directive (:arg, :type, :rtype, :return)
     # but NOT :class: or :func: which appear inside type annotations
-    directive_lookahead = r"(?=\n\s*:(?:arg|param|type|rtype|return|returns|raises)[\s:]|$)"
+    directive_lookahead = (
+        r"(?=\n\s*:(?:arg|param|type|rtype|return|returns|raises)[\s:]|$)"
+    )
     for match in re.finditer(
         rf":type\s+(\w+):\s*(.+?){directive_lookahead}", docstring, re.DOTALL
     ):
@@ -890,6 +892,29 @@ def parse_rst_function_sig(
     return result
 
 
+# Bare mathutils types that Blender's C code accepts interchangeably with
+# Sequence[float] via mathutils_array_parse.  When a param is typed as one
+# of these in a docstring, widen it to also accept Sequence[float].
+_MATHUTILS_ARRAY_TYPES = {
+    "mathutils.Vector",
+    "mathutils.Euler",
+    "mathutils.Quaternion",
+    "mathutils.Color",
+    "Vector",
+    "Euler",
+    "Quaternion",
+    "Color",
+}
+
+
+def _widen_mathutils_params(params: list[ParamData]) -> None:
+    """Widen bare mathutils type params to also accept Sequence[float]."""
+    for param in params:
+        ptype = param.get("type")
+        if ptype and ptype in _MATHUTILS_ARRAY_TYPES:
+            param["type"] = f"{ptype} | Sequence[float]"
+
+
 def introspect_callable(func: Callable[..., object], name: str) -> FunctionData | None:
     """Introspect a callable (function or builtin) and return its metadata."""
     docstring = inspect.getdoc(func) or ""
@@ -947,6 +972,7 @@ def introspect_callable(func: Callable[..., object], name: str) -> FunctionData
                         "kind": "POSITIONAL_OR_KEYWORD",
                     }
                 )
+        _widen_mathutils_params(params)
         return {
             "name": name,
             "doc": clean_docstring(docstring),
@@ -959,9 +985,7 @@ def introspect_callable(func: Callable[..., object], name: str) -> FunctionData
     # C functions often use generic names like "object" in __text_signature__
     # while docstrings use descriptive names like "string", "cls", etc.
     doc_param_list = list(param_types.items())
-    sig_param_list = [
-        (n, p) for n, p in sig.parameters.items() if n != "self"
-    ]
+    sig_param_list = [(n, p) for n, p in sig.parameters.items() if n != "self"]
 
     params = []
     for i, (pname, param) in enumerate(sig_param_list):
@@ -991,6 +1015,7 @@ def introspect_callable(func: Callable[..., object], name: str) -> FunctionData
             }
         )
 
+    _widen_mathutils_params(params)
     return {
         "name": name,
         "doc": clean_docstring(docstring),
@@ -1099,6 +1124,7 @@ def _parse_class_constructor(class_doc: str, cls: type) -> FunctionData | None:
     if not params:
         return None
 
+    _widen_mathutils_params(params)
     return {
         "name": "__init__",
         "doc": "",
@@ -1192,7 +1218,7 @@ def _fix_dunder_signatures(
             method["params"] = [
                 {
                     "name": "key",
-                    "type": "int",
+                    "type": "int | slice",
                     "default": None,
                     "kind": "POSITIONAL_OR_KEYWORD",
                 }
@@ -1216,7 +1242,7 @@ def _fix_dunder_signatures(
                 method["params"] = [
                     {
                         "name": "key",
-                        "type": "int",
+                        "type": "int | slice",
                         "default": None,
                         "kind": "POSITIONAL_OR_KEYWORD",
                     }
@@ -1244,13 +1270,13 @@ def _fix_dunder_signatures(
                 method["params"] = [
                     {
                         "name": "key",
-                        "type": "int",
+                        "type": "int | slice",
                         "default": None,
                         "kind": "POSITIONAL_OR_KEYWORD",
                     },
                     {
                         "name": "value",
-                        "type": vtype,
+                        "type": f"{vtype} | Sequence[{vtype}]",
                         "default": None,
                         "kind": "POSITIONAL_OR_KEYWORD",
                     },
@@ -1304,6 +1330,31 @@ def _fix_dunder_signatures(
             continue
 
 
+def _is_getset_writable(cls: type[object], attr_name: str) -> bool:
+    """Test if a C getset_descriptor property is writable.
+
+    C getset_descriptors that have a setter implement __set__.
+    Those without a setter raise AttributeError on __set__ calls.
+    We test this by checking if __set__ raises on a dummy call.
+    """
+    descriptor = cls.__dict__.get(attr_name)
+    if descriptor is None:
+        return False
+    # If the descriptor doesn't implement __set__ at all, it's read-only
+    if not hasattr(descriptor, "__set__"):
+        return False
+    # Try calling __set__ with None — a writable descriptor will attempt
+    # the set (and fail on None), while a read-only one raises AttributeError
+    try:
+        descriptor.__set__(None, None)
+    except AttributeError:
+        return False
+    except Exception:
+        # Any other error means __set__ exists (it just didn't like our args)
+        return True
+    return True
+
+
 def introspect_class(cls: type[object], module_name: str) -> StructData:
     """Introspect a class (C extension or Python) and return StructData."""
     # Determine base class (skip object and internal bases)
@@ -1361,7 +1412,11 @@ def introspect_class(cls: type[object], module_name: str) -> StructData:
         elif isinstance(raw, property) or type(raw).__name__ == "getset_descriptor":
             doc = inspect.getdoc(raw) or ""
             _, rtype = parse_docstring_types(doc)
-            is_readonly = not hasattr(raw, "fset") or raw.fset is None
+            if isinstance(raw, property):
+                is_readonly = raw.fset is None
+            else:
+                # C getset_descriptors don't expose fset; probe at runtime
+                is_readonly = not _is_getset_writable(cls, name)
             properties.append(
                 {
                     "name": name,

main.py

@@ -441,6 +441,7 @@ def conformance_check(versions: list[str] | None = None) -> None:
                     "extraPaths": [str(version_dir)],
                     "typeCheckingMode": "strict",
                     "pythonVersion": python_version,
+                    "reportUnusedExpression": False,
                 }
             )
         )

overrides/5.0/mathutils.json

@@ -0,0 +1,12 @@
+{
+  "Matrix.Translation": {
+    "params": {
+      "vector": "Vector | Sequence[float]"
+    }
+  },
+  "Matrix.Scale": {
+    "params": {
+      "axis": "Vector | Sequence[float]"
+    }
+  }
+}