Add additional annotations to avoid typing issues (#92897)

BlendFileBlock attributes:

Explicit annotation on BlendFileBlock are needed because otherwise
e.g. `block.add_old` type was imprecisely inferred from the
assignments as `int | Any`, where `Any` comes from `.unpack` returning
`tuple[Any, ...]`.

Ideally unpack should be somehow connected to the returned types, but
this solution should work for now just to avoid typing errors.

dna_io - add some missing annotations:

Some annotations were needed to ensure `block.code` will be inferred
as `bytes` and not `bytes | Unknown`.

Reviewed-on: https://projects.blender.org/blender/blender-asset-tracer/pulls/92897
Reviewed-by: Sybren A. Stüvel <sybren@blender.org>

blender_asset_tracer/blendfile/__init__.py

@@ -447,6 +447,12 @@ class BlendFileBlock:
     old_structure = struct.Struct(b"4sI")
     """old blend files ENDB block structure"""
 
+    # Explicitly annotate to avoid `Any` from `.unpack()`.
+    size: int
+    addr_old: int
+    sdna_index: int
+    count: int
+
     def __init__(self, bfile: BlendFile) -> None:
         self.bfile = bfile
 

blender_asset_tracer/blendfile/dna_io.py

@@ -204,17 +204,17 @@ class EndianIO:
         return fileobj.write(to_write)
 
     @classmethod
-    def read_bytes0(cls, fileobj, length):
+    def read_bytes0(cls, fileobj: typing.IO[bytes], length: int) -> bytes:
         data = fileobj.read(length)
         return cls.read_data0(data)
 
     @classmethod
-    def read_data0_offset(cls, data, offset):
+    def read_data0_offset(cls, data: bytes, offset: int) -> bytes:
         add = data.find(b"\0", offset) - offset
         return data[offset : offset + add]
 
     @classmethod
-    def read_data0(cls, data):
+    def read_data0(cls, data: bytes) -> bytes:
         add = data.find(b"\0")
         if add < 0:
             return data