Use UV to install executorch

[liu-mengyang]

Anyone use uv to install executorch successfully? I have tried multiple times whatever on ARM-based macbook or Linux-based server but uv always failed in executing ./install_executorch.sh. I have no choice but to use conda. If you achieved success installation via uv, I hope you can share your detailed process, thanks!

[cccclai]

Hmm I'm not aware people trying it. Maybe @mergennachin or @larryliu0820 knows

[cccclai]

Is there any specific reason you're trying uv?

[liu-mengyang]

Is there any specific reason you're trying uv?

There’s no hard requirement from my side. It’s mainly a personal preference for using uv as the Python package manager.

My current guess is that the failure is specific to how uv handles builds: it runs installs with build isolation and more aggressive parallelism, and ./install_executorch.sh seems to rely on some CMake-built extensions being available in a particular order or environment. So I suspect uv is invoking pip install / CMake in a way that breaks those assumptions.

Maybe I can explore some uv configuration options to preserve the correct build order during the build process. :)

[liu-mengyang]

By applying some minor changes in install_executorch.py and install_requirements.py to replace python -m pip install with uv pip install, uv successfully installed executorch.

[cccclai]

Wow nice! Can you sharing the changes you made?

[liu-mengyang]

Sure!

# install_executorch.py - Line 207

     cmd = (
-        [
-            sys.executable,
-            "-m",
-            "pip",
-            "install",
-        ]
+        (["uv", "pip"] if shutil.which("uv") else [sys.executable, "-m", "pip"])
+        + ["install"]
         + (["--editable"] if args.editable else [])
         + [
            ".",
            "--no-build-isolation",
            "-v",
           ]
     )

# install_requirements.py - Line 69

    # Install the requirements for core ExecuTorch package.

+    # UV skips default index url, so we need to split the command into two parts.
+    subprocess.run(
+        (["uv", "pip"] if shutil.which("uv") else [sys.executable, "-m", "pip"])
+        + ["install", "-r", "requirements-dev.txt"],
+        check=True,
+    )

    subprocess.run(
-        [
-            sys.executable,
-            "-m",
-            "pip",
-            "install",
-            "-r",
-            "requirements-dev.txt",
-            *TORCH_PACKAGE,
-            "--extra-index-url",
-            torch_url,
-        ],
+        ["pip", "install", *TORCH_PACKAGE, "--extra-index-url", torch_url],
        check=True,
    )

...

# install_requirements.py - Line 93

    # Install packages directly from local copy instead of pypi.
    # This is usually not recommended.
    new_env = os.environ.copy()
    if ("EXECUTORCH_BUILD_KERNELS_TORCHAO" not in new_env) or (
        new_env["EXECUTORCH_BUILD_KERNELS_TORCHAO"] == "0"
    ):
        new_env["USE_CPP"] = "0"
    else:
        assert new_env["EXECUTORCH_BUILD_KERNELS_TORCHAO"] == "1"
        new_env["USE_CPP"] = "1"
        new_env["CMAKE_POLICY_VERSION_MINIMUM"] = "3.5"
    subprocess.run(
-        [
-            sys.executable,
-            "-m",
-            "pip",
-            "install",
-            # Without --no-build-isolation, setup.py can't find the torch module.
-            "--no-build-isolation",
-            *LOCAL_REQUIREMENTS,
-        ],
+        (["uv", "pip"] if shutil.which("uv") else [sys.executable, "-m", "pip"])
+        + ["install", "--no-build-isolation", *LOCAL_REQUIREMENTS],
        env=new_env,
        check=True,
    )

...

# install_requirements.py - Line 130

    # Then install domain libraries
    subprocess.run(
-        [
-            sys.executable,
-            "-m",
-            "pip",
-            "install",
-            *DOMAIN_LIBRARIES,
-            "--extra-index-url",
-            torch_url,
-        ],
+        (["uv", "pip"] if shutil.which("uv") else [sys.executable, "-m", "pip"])
+        + ["install", *DOMAIN_LIBRARIES, "--extra-index-url", torch_url],
        check=True,
    )

    print("Installing packages in requirements-examples.txt")
-    subprocess.run(
-        [
-            sys.executable,
-            "-m",
-            "pip",
-            "install",
-            "-r",
-            "requirements-examples.txt",
-            "--extra-index-url",
-            torch_url,
-            "--upgrade-strategy",
-            "only-if-needed",
-        ],
-        check=True,
-    )
+    cmd = (
+        (["uv", "pip"] if shutil.which("uv") else [sys.executable, "-m", "pip"])
+        + ["install", "-r", "requirements-examples.txt", "--extra-index-url", torch_url]
+    )
+    # Only add --upgrade-strategy for regular pip, not uv
+    if not shutil.which("uv"):
+        cmd.extend(["--upgrade-strategy", "only-if-needed"])
+    else:
+        cmd.extend(["--index-strategy", "unsafe-best-match"])
+    subprocess.run(cmd, check=True)