From 091c204b0a19bea3e9a4ffebdc69750117843220 Mon Sep 17 00:00:00 2001
From: "Robin.Schmidt" <robin.schmidt@winkhaus.de>
Date: Fri, 14 Aug 2026 11:39:27 +0200
Subject: [PATCH] Fixed typing of `Construct._build()`.

---
 CHANGELOG.md             |  6 +++++-
 construct-stubs/core.pyi |  4 +++-
 tests/test_core.py       | 10 ++++++++++
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e88943a..9749361 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## [Unreleased]
+**Fixes:**
+- Fixed return type of `Construct._build()`: `int` was wrong and worked only in specific cases.
+
 ## [0.8.1] - 2026-07-23
 **New features:**
 - Added `Subconstruct`, `SymmetricAdapter`, `Tunnel` and `Validator` to `construct_typed` as subscriptable types.
@@ -23,4 +27,4 @@
 - Use PEP604 union syntax "X | Y" instead of "Union[X, Y]" and "X | None" instead of "Optional[X]" in type hints.
 
 **Organizational changes:**
-- Use `uv` as a project management tool and `poe` as a task runner.
\ No newline at end of file
+- Use `uv` as a project management tool and `poe` as a task runner.
diff --git a/construct-stubs/core.pyi b/construct-stubs/core.pyi
index 361c2ab..66dffb4 100644
--- a/construct-stubs/core.pyi
+++ b/construct-stubs/core.pyi
@@ -164,9 +164,11 @@ class Construct(t.Generic[ParsedType, BuildTypes]):
     def _parsereport(
         self, stream: StreamType, context: Context, path: PathType
     ) -> ParsedType: ...
+    # In most implementations, `_build()` actually returns `ParsedType`, in some others it
+    # returns `BuildTypes` or something else entirely. `t.Any` seems a good compromise.
     def _build(
         self, obj: BuildTypes, stream: StreamType, context: Context, path: PathType
-    ) -> int: ...
+    ) -> t.Any: ...
     def _sizeof(self, context: Context, path: PathType) -> int: ...
 
 @t.type_check_only
diff --git a/tests/test_core.py b/tests/test_core.py
index aad3516..6e6b33b 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -1781,6 +1781,16 @@ def __init__(
                 hashfunc: t.Callable[[bytes], BuildTypes],
                 bytesfunc: t.Callable[[Context], bytes],
             ) -> None: ...
+
+            def _parse(self, stream: t.IO[bytes], context: Context, path: str) -> ParsedType:
+                ...
+
+            def _build(self, obj: BuildTypes, stream: t.IO[bytes], context: Context, path: str) -> t.Any:
+                ...
+
+            def _sizeof(self, context: Context, path: str) -> int:
+                ...
+
     else:
         import binascii