Restore accidentally removed python-venv-stubber.sh

Author: mxcl

libexec/python-venv-stubber.sh

@@ -0,0 +1,72 @@
+#!/usr/bin/env -S pkgx bash
+# shellcheck shell=bash
+
+# python virtual-envs are not relocatable
+# our only working choice is to rewrite these files and symlinks every time
+# because we promise that pkgx is relocatable *at any time*
+#FIXME requiring sed is a bit lame
+
+if test -z "$VIRTUAL_ENV"; then
+  echo "error: VIRTUAL_ENV not set" >&2
+  exit 1
+fi
+
+mkdir -p "$VIRTUAL_ENV/../bin"
+
+CMD_NAME="$1"
+
+cat <<EOF > "$VIRTUAL_ENV"/../bin/"$CMD_NAME"
+#!/usr/bin/env python
+
+import os
+import sys
+import glob
+import shutil
+from pathlib import Path
+
+# Determine directories and paths
+script_dir = os.path.dirname(os.path.realpath(__file__))
+virtual_env = os.path.normpath(os.path.join(script_dir, '..', 'venv'))
+arg0 = os.path.basename(sys.argv[0])
+python_path = shutil.which('python')
+python_home = os.path.dirname(python_path)
+
+# Write pyvenv.cfg file
+pyvenv_cfg_path = os.path.join(virtual_env, 'pyvenv.cfg')
+with open(pyvenv_cfg_path, 'w') as f:
+    f.write(f"home = {python_home}\ninclude-system-site-packages = false\nexecutable = {python_path}\n")
+
+new_first_line = b"#!" + os.path.join(virtual_env, 'bin', 'python').encode('utf-8') + b"\n"
+
+# Go through files in the bin directory
+for filepath in glob.glob(os.path.join(virtual_env, 'bin', '*')):
+    if os.path.isfile(filepath) and not os.path.islink(filepath):
+        with open(filepath, 'rb+') as f:
+          first_two_chars = f.read(2)
+
+          if first_two_chars == b'#!':
+              old_first_line = first_two_chars + f.readline()  # Read the rest of the first line
+
+              if old_first_line.strip().endswith(b"python") and old_first_line != new_first_line:
+                  rest_of_file = f.read()
+                  f.seek(0)
+                  f.write(new_first_line + rest_of_file)
+                  f.truncate()
+
+# Create symlink to the specified Python version in the virtual environment
+python_symlink = os.path.join(virtual_env, 'bin', 'python')
+
+# Remove the symbolic link if it already exists
+if os.path.islink(python_symlink) or os.path.exists(python_symlink):
+    os.remove(python_symlink)
+
+os.symlink(python_path, python_symlink)
+
+# Execute the corresponding script in the virtual environment
+arg0 = os.path.join(virtual_env, 'bin', arg0)
+args = sys.argv[1:]
+args.insert(0, arg0)
+os.execv(arg0, args)
+EOF
+
+chmod +x "$VIRTUAL_ENV/../bin/$CMD_NAME"