From 350b5436480610aa57e63c6e57752d1f53b199c8 Mon Sep 17 00:00:00 2001
From: Gonzalo Casas <casas@arch.ethz.ch>
Date: Thu, 4 Jun 2026 16:33:10 +0200
Subject: [PATCH] Make build-cpython-ghuser-components work on macOS/Linux
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Run the componentizer as a direct subprocess (sys.executable) instead of
through a shell, and on macOS force the Mono runtime and add the Homebrew
library dirs to DYLD_LIBRARY_PATH.

The componentizer loads GH_IO.dll via pythonnet, so no Rhino/Windows is
required — only a .NET runtime. On macOS that's Mono, which needs the native
libgdiplus to embed component icons. Two things broke this off Windows:

- The Mono that pythonnet embeds doesn't search the Homebrew prefix the way
  the `mono` CLI does, so libgdiplus wasn't found. Setting DYLD_LIBRARY_PATH
  to $(brew --prefix)/lib (plus the standard /opt/homebrew and /usr/local
  prefixes) fixes resolution.
- macOS SIP strips DYLD_* when a command crosses the protected /bin/sh, which
  is what invoke's ctx.run spawns. Calling the interpreter directly via
  subprocess.run keeps the variable alive.

Windows and Linux behaviour is unchanged (env returned untouched).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 CHANGELOG.md                     |  2 ++
 src/compas_invocations2/build.py | 43 +++++++++++++++++++++++++++++---
 2 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e5c4013..b57bed0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+* `build-cpython-ghuser-components` now runs the componentizer as a direct subprocess (using `sys.executable`) instead of through a shell, and on macOS forces the Mono runtime and adds the Homebrew library directories to `DYLD_LIBRARY_PATH`. This makes the task work on macOS (and Linux) without Rhino/Windows — previously the embedded Mono could not find `libgdiplus` to embed component icons, and macOS SIP stripped `DYLD_*` across the shell `ctx.run` used.
+
 ### Removed
 
 
diff --git a/src/compas_invocations2/build.py b/src/compas_invocations2/build.py
index 62b448e..6041274 100644
--- a/src/compas_invocations2/build.py
+++ b/src/compas_invocations2/build.py
@@ -1,6 +1,9 @@
 import glob
 import os
+import platform
 import shutil
+import subprocess
+import sys
 import tempfile
 
 import invoke
@@ -173,12 +176,44 @@ def build_cpython_ghuser_components(ctx, gh_io_folder=None, prefix=None):
             gh_io_folder = os.path.abspath(gh_io_folder)
             componentizer_script = os.path.join(action_dir, "componentize_cpy.py")
 
-            cmd = "{} {} {} {}".format("python", componentizer_script, source_dir, target_dir)
-            cmd += ' --ghio "{}"'.format(gh_io_folder)
+            cmd = [sys.executable, componentizer_script, source_dir, target_dir, "--ghio", gh_io_folder]
             if prefix:
-                cmd += ' --prefix "{}"'.format(prefix)
+                cmd += ["--prefix", prefix]
 
-            ctx.run(cmd)
+            # The componentizer loads GH_IO.dll through pythonnet. On macOS that means Mono,
+            # which needs the native libgdiplus to embed component icons. The embedded Mono
+            # does not search the Homebrew prefix the way the `mono` CLI does, so we point it
+            # there via DYLD_LIBRARY_PATH. We also run the interpreter directly instead of
+            # through `ctx.run` (which spawns a shell): macOS SIP strips DYLD_* across the
+            # protected /bin/sh, so otherwise the variable never reaches the subprocess.
+            subprocess.run(cmd, env=_componentizer_env(), check=True)
+
+
+def _componentizer_env():
+    """Return the environment for the componentizer subprocess.
+
+    On macOS this forces the Mono runtime (pythonnet may otherwise default to a
+    .NET Core runtime that cannot load the net48 ``GH_IO.dll`` / ``System.Drawing``)
+    and adds the Homebrew library directories to ``DYLD_LIBRARY_PATH`` so Mono can
+    find ``libgdiplus``. On other platforms the current environment is returned
+    unchanged.
+    """
+    env = dict(os.environ)
+    if platform.system() != "Darwin":
+        return env
+
+    env.setdefault("PYTHONNET_RUNTIME", "mono")
+
+    lib_dirs = ["/opt/homebrew/lib", "/usr/local/lib"]
+    try:
+        brew_prefix = subprocess.check_output(["brew", "--prefix"], text=True).strip()
+        lib_dirs.insert(0, os.path.join(brew_prefix, "lib"))
+    except (OSError, subprocess.CalledProcessError):
+        pass
+    if env.get("DYLD_LIBRARY_PATH"):
+        lib_dirs.append(env["DYLD_LIBRARY_PATH"])
+    env["DYLD_LIBRARY_PATH"] = os.pathsep.join(dict.fromkeys(d for d in lib_dirs if d))
+    return env
 
 
 @invoke.task