Support uv in ExecuTorch installation scripts

docs/source/using-executorch-building-from-source.md

@@ -61,6 +61,17 @@ portability details.
    conda activate executorch
    ```
 
+Alternatively, on macOS or Linux, create and activate a virtual environment with uv:
+
+```bash
+uv venv --python 3.12 .venv
+source .venv/bin/activate
+```
+
+The installation scripts use pip when it is available in the current Python
+environment, or fall back to `uv pip` when uv is on `PATH`. There is no need to
+seed pip before running the installer.
+
 > **_NOTE:_** Additional Windows Setup
 >
 > ExecuTorch requires symlinks to be enabled to build the Python components. To enable symlinks, run the following command before cloning the repository. Missing symlinks will manifest as an error related to `version.py` when running `pip install .`. See [src/README.md](https://github.com/pytorch/executorch/blob/main/src/README.md) for more information.

install_executorch.py

@@ -20,6 +20,7 @@
     install_requirements,
     python_is_compatible,
 )
+from install_utils import get_package_install_command
 
 # Set up logging
 logging.basicConfig(
@@ -237,12 +238,7 @@ def main(args):
         extras = ",".join(dict.fromkeys(args.optional_dependency))
         package_spec = f".[{extras}]"
     cmd = (
-        [
-            sys.executable,
-            "-m",
-            "pip",
-            "install",
-        ]
+        [*get_package_install_command()]
         + (["--editable"] if args.editable else [])
         + [
             package_spec,

install_requirements.py

@@ -11,7 +11,12 @@
 import subprocess
 import sys
 
-from install_utils import determine_torch_url, is_intel_mac_os, python_is_compatible
+from install_utils import (
+    determine_torch_url,
+    get_package_install_command,
+    is_intel_mac_os,
+    python_is_compatible,
+)
 
 # The pip repository that hosts nightly torch packages.
 # This will be dynamically set based on CUDA availability and CUDA backend enabled/disabled.
@@ -114,10 +119,7 @@ def install_requirements(use_pytorch_nightly):
     # versions on the provided URL if they aren't available on the default URL.
     subprocess.run(
         [
-            sys.executable,
-            "-m",
-            "pip",
-            "install",
+            *get_package_install_command(),
             "-r",
             "requirements-dev.txt",
             *TORCH_PACKAGE,
@@ -142,10 +144,7 @@ def install_requirements(use_pytorch_nightly):
             )
             subprocess.run(
                 [
-                    sys.executable,
-                    "-m",
-                    "pip",
-                    "install",
+                    *get_package_install_command(),
                     "--no-build-isolation",
                     "sentencepiece==0.2.2",
                 ],
@@ -170,10 +169,7 @@ def install_requirements(use_pytorch_nightly):
             new_env["CMAKE_POLICY_VERSION_MINIMUM"] = "3.5"
         subprocess.run(
             [
-                sys.executable,
-                "-m",
-                "pip",
-                "install",
+                *get_package_install_command(),
                 # Without --no-build-isolation, setup.py can't find the torch module.
                 "--no-build-isolation",
                 *LOCAL_REQUIREMENTS,
@@ -214,10 +210,7 @@ def install_optional_example_requirements(use_pytorch_nightly):
     # Then install domain libraries
     subprocess.run(
         [
-            sys.executable,
-            "-m",
-            "pip",
-            "install",
+            *get_package_install_command(),
             *DOMAIN_LIBRARIES,
             "--extra-index-url",
             torch_url,
@@ -229,18 +222,13 @@ def install_optional_example_requirements(use_pytorch_nightly):
     print("Installing packages in requirements-examples.txt")
     subprocess.run(
         [
-            sys.executable,
-            "-m",
-            "pip",
-            "install",
+            *get_package_install_command(),
             "-r",
             "requirements-examples.txt",
             *cu134_packages,
             "--extra-index-url",
             torch_url,
             *torchao_index,
-            "--upgrade-strategy",
-            "only-if-needed",
         ],
         check=True,
     )

install_utils.py

@@ -6,6 +6,7 @@
 # LICENSE file in the root directory of this source tree.
 
 import functools
+import importlib.util
 import os
 import platform
 import re
@@ -25,6 +26,33 @@
 )
 
 
+@functools.lru_cache(maxsize=1)
+def get_package_install_command() -> Tuple[str, ...]:
+    """Choose an installer once, even if requirements later install pip."""
+    if importlib.util.find_spec("pip") is not None:
+        return (sys.executable, "-m", "pip", "install")
+
+    uv = shutil.which("uv")
+    if uv is not None:
+        return (
+            uv,
+            "pip",
+            "install",
+            "--python",
+            sys.executable,
+            # Match pip's selection across the PyTorch and PyPI indexes.
+            "--index-strategy",
+            "unsafe-best-match",
+        )
+
+    raise RuntimeError(
+        "Neither pip nor uv is available. "
+        f'Install pip with "{sys.executable} -m ensurepip --upgrade", '
+        "or install uv and ensure it is on PATH: "
+        "https://docs.astral.sh/uv/getting-started/installation/"
+    )
+
+
 def is_cmake_option_on(
     cmake_configuration_args: List[str], var_name: str, default: bool
 ) -> bool:
@@ -397,9 +425,7 @@ def python_is_compatible():
     try:
         import packaging
     except ImportError:
-        subprocess.run(
-            [sys.executable, "-m", "pip", "install", "packaging"], check=True
-        )
+        subprocess.run([*get_package_install_command(), "packaging"], check=True)
     # Compare the current python version to the range in version_specifier. Exits
     # with status 1 if the version is not compatible, or with status 0 if the
     # version is compatible or the logic itself fails.