Update pip install commands for intel macOS systems and pytorch versions built from source

Author: keyprocedure

install_requirements.py

@@ -75,49 +75,58 @@ def python_is_compatible():
 
 
 def install_requirements(use_pytorch_nightly):
-    # Prevent pip install attempt on Intel-based macOS (no prebuilt PyTorch binaries available)
-    if use_pytorch_nightly and is_intel_mac_os():
+    is_intel_mac = is_intel_mac_os()
+
+    # Skip pip install on Intel macOS if using nightly.
+    if use_pytorch_nightly and is_intel_mac:
         sys.exit(1)
 
     # pip packages needed by exir.
     EXIR_REQUIREMENTS = [
         # Setting use_pytorch_nightly to false to test the pinned PyTorch commit. Note
         # that we don't need to set any version number there because they have already
         # been installed on CI before this step, so pip won't reinstall them
-        f"torch==2.8.0.{NIGHTLY_VERSION}" if use_pytorch_nightly else "torch",
-        (
-            f"torchvision==0.22.0.{NIGHTLY_VERSION}"
-            if use_pytorch_nightly
-            else "torchvision"
-        ),  # For testing.
+        f"torch==2.8.0.{NIGHTLY_VERSION}" if use_pytorch_nightly else "torch"
     ]
 
-    EXAMPLES_REQUIREMENTS = [
-        f"torchaudio==2.6.0.{NIGHTLY_VERSION}" if use_pytorch_nightly else "torchaudio",
-    ]
+    EXAMPLES_REQUIREMENTS = []
+
+    # Only pip install torchvision and torchaudio if not building PyTorch from source on Intel macOS,
+    # to avoid installing incompatible prebuilt wheels from PyPI.
+    if not is_intel_mac:
+        EXIR_REQUIREMENTS.append(
+            f"torchvision==0.22.0.{NIGHTLY_VERSION}"
+        )  # For testing.
+
+        EXAMPLES_REQUIREMENTS = [
+            f"torchaudio==2.6.0.{NIGHTLY_VERSION}",
+        ]
 
     # Assemble the list of requirements to actually install.
     # TODO: Add options for reducing the number of requirements.
     REQUIREMENTS_TO_INSTALL = EXIR_REQUIREMENTS + EXAMPLES_REQUIREMENTS
 
     # Install the requirements. `--extra-index-url` tells pip to look for package
     # versions on the provided URL if they aren't available on the default URL.
-    subprocess.run(
-        [
-            sys.executable,
-            "-m",
-            "pip",
-            "install",
-            "-r",
-            "requirements-examples.txt",
-            "-r",
-            "requirements-dev.txt",
-            *REQUIREMENTS_TO_INSTALL,
-            "--extra-index-url",
-            TORCH_NIGHTLY_URL,
-        ],
-        check=True,
-    )
+    pip_args = [
+        sys.executable,
+        "-m",
+        "pip",
+        "install",
+        "-r",
+        "requirements-examples.txt",
+        "-r",
+        "requirements-dev.txt",
+        *REQUIREMENTS_TO_INSTALL,
+        "--extra-index-url",
+        TORCH_NIGHTLY_URL,
+    ]
+
+    # If pytorch is built from source add no-deps flag to stop dependencies from changing torch version
+    if not use_pytorch_nightly:
+        pip_args.append("--no-deps")
+
+    subprocess.run(pip_args, check=True)
 
     LOCAL_REQUIREMENTS = [
         "third-party/ao",  # We need the latest kernels for fast iteration, so not relying on pypi.
@@ -143,18 +152,18 @@ def install_requirements(use_pytorch_nightly):
     )
 
 
-# Prebuilt binaries for Intel-based macOS are no longer available on PyPI; users must compile from source.
+# Prebuilt wheels for Intel macOS are no longer available on PyPI; users must compile from source.
 # PyTorch stopped building macOS x86_64 binaries since version 2.3.0 (January 2024).
 def is_intel_mac_os():
-    # Returns True if running on Intel-based macOS
+    # Returns True if running on Intel macOS
     if platform.system().lower() == "darwin" and platform.machine().lower() in (
         "x86",
         "x86_64",
         "i386",
     ):
         print(
-            "ERROR: Prebuilt PyTorch binaries are no longer available for Intel-based macOS.\n"
-            "Please compile from source by following https://pytorch.org/executorch/0.6/using-executorch-building-from-source.html",
+            "ERROR: Prebuilt PyTorch wheels are no longer available for Intel-based macOS.\n"
+            "Please build from source by following https://pytorch.org/executorch/0.6/using-executorch-building-from-source.html",
             file=sys.stderr,
         )
         return True