Update

[ghstack-poisoned]

Author: swolchok

setup.py

@@ -237,11 +237,11 @@ def src_path(self, installer: "InstallerBuildExt") -> Path:
         srcs = tuple(cmake_cache_dir.glob(self.src))
         if len(srcs) != 1:
             raise ValueError(
-                f"""Expected exactly one file matching '{self.src}'; found {repr(srcs)}. 
+                f"""Expected exactly one file matching '{self.src}'; found {repr(srcs)}.
 
 If that file is a CMake-built extension module file, and we are installing in editable mode, please disable the corresponding build option since it's not supported yet.
 
-Try: 
+Try:
 
 EXECUTORCH_BUILD_FLATC=OFF EXECUTORCH_BUILD_KERNELS_CUSTOM_AOT=OFF pip install -e .
 """
@@ -611,9 +611,9 @@ def run(self):
         # for multi-config generators.
         build_args += ["--config", cfg]
 
-        # Put the cmake cache under the temp directory, like
-        # "pip-out/temp.<plat>/cmake-out".
-        cmake_cache_dir = os.path.join(repo_root, self.build_temp, "cmake-out")
+        # Share the cmake-out directory with any other cmake builds the user/developer
+        # might do, rather than hiding it under build_temp.
+        cmake_cache_dir = os.path.join(repo_root, "cmake-out")
         self.mkpath(cmake_cache_dir)
 
         # Generate the cmake cache from scratch to ensure that the cache state