From 7a885eaa095de739c3bf49286ce6d55c736ee5b4 Mon Sep 17 00:00:00 2001
From: Zanie Blue <contact@zanie.dev>
Date: Fri, 6 Dec 2024 14:08:00 -0600
Subject: [PATCH] Add hint on build backend import with preview disabled
 (#9691)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

See #9686

```
❯ uv run python -c "import uv; uv.build_sdist"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/Users/zb/workspace/uv/python/uv/__init__.py", line 45, in __getattr__
    raise AttributeError(err)
AttributeError: Using `uv.build_sdist` is not allowed. The uv build backend requires preview mode to be
                enabled, e.g., via the `UV_PREVIEW=1` environment variable.

❯ uv run python -c "import uv; uv.foo"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/Users/zb/workspace/uv/python/uv/__init__.py", line 48, in __getattr__
    raise AttributeError(err)
AttributeError: module 'uv' has no attribute 'foo'

❯ uv run python -c "import uv; uv.find_uv_bin"
```
---
 python/uv/__init__.py | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/python/uv/__init__.py b/python/uv/__init__.py
index 5ad0fde7c..5f18152af 100644
--- a/python/uv/__init__.py
+++ b/python/uv/__init__.py
@@ -28,3 +28,21 @@ if os.environ.get("UV_PREVIEW"):
     ]
 else:
     __all__ = ["find_uv_bin"]
+
+
+def __getattr__(attr_name: str) -> object:
+    if attr_name in {
+        "build_sdist",
+        "build_wheel",
+        "build_editable",
+        "get_requires_for_build_sdist",
+        "get_requires_for_build_wheel",
+        "prepare_metadata_for_build_wheel",
+        "get_requires_for_build_editable",
+        "prepare_metadata_for_build_editable",
+    }:
+        err = f"Using `uv.{attr_name}` is not allowed. The uv build backend requires preview mode to be enabled, e.g., via the `UV_PREVIEW=1` environment variable."
+        raise AttributeError(err)
+
+    err = f"module 'uv' has no attribute '{attr_name}'"
+    raise AttributeError(err)