meson: Port meson_dist_script.sh to Python

It's not used by Windows right now, but it can be so let's port it.

meson.build

@@ -1905,7 +1905,7 @@ custom_target('Changelog',
   build_by_default: false,
 )
 
-meson.add_dist_script('meson_dist_script.sh',
+meson.add_dist_script('meson_dist_script.py',
                       generate_version_h ?  gitversion_h.full_path() : gitversion_h,
                       meson.project_source_root(), meson.project_build_root())
 

meson_dist_script.py

@@ -0,0 +1,39 @@
+#!/usr/bin/env python3
+import os
+import subprocess
+import sys
+import shutil
+
+GIT_VERSION_H = sys.argv[1]
+
+MESON_SOURCE_ROOT = os.environ.get('MESON_SOURCE_ROOT', sys.argv[2])
+MESON_BUILD_ROOT = os.environ.get('MESON_BUILD_ROOT', sys.argv[3])
+
+# `meson dist` doesn't trigger a build, which is a problem because we
+# need to add some configured/built files. The case where we didn't
+# build at all is the less annoying (we'd get a failure, which is
+# actually acceptable as it warns us). But the case where we would copy
+# outdated data is much more insidious (such as wrong INSTALL
+# information or wrong git information) as it would be silent.
+# See: https://github.com/mesonbuild/meson/issues/10650
+# And: https://gitlab.gnome.org/GNOME/gimp/-/issues/7907
+# This is why we manually trigger, not only a reconfigure, but also a
+# rebuild of the main project before copying data around.
+
+try:
+  # INSTALL file is generated at configure time.
+  subprocess.run(['meson', '--reconfigure', MESON_SOURCE_ROOT], check=True)
+  # git-version.h is generated at build time.
+  subprocess.run(['meson', 'compile'], check=True)
+
+  shutil.copy2('INSTALL', os.environ['MESON_DIST_ROOT'])
+  install_in = os.path.join(os.environ['MESON_DIST_ROOT'], 'INSTALL.in')
+  if os.path.exists(install_in):
+    os.remove(install_in)
+
+  shutil.copy2(GIT_VERSION_H, os.environ['MESON_DIST_ROOT'])
+
+except subprocess.CalledProcessError as e:
+  sys.exit(e.returncode)
+except Exception:
+  sys.exit(1)

meson_dist_script.sh

@@ -1,35 +0,0 @@
-#!/usr/bin/env bash
-
-GIT_VERSION_H="$1"
-
-# MESON_SOURCE_ROOT and MESON_BUILD_ROOT environment variables are
-# passed since meson 0.54.0 but we depend on 0.53.0 so I also pass them
-# as script arguments. When we bump out meson requirement, this test may
-# go away.
-if [ -z "$MESON_SOURCE_ROOT" ]; then
-  MESON_SOURCE_ROOT="$2"
-fi
-if [ -z "$MESON_BUILD_ROOT" ]; then
-  MESON_BUILD_ROOT="$3"
-fi
-
-# `meson dist` doesn't trigger a build, which is a problem because we
-# need to add some configured/built files. The case where we didn't
-# build at all is the less annoying (we'd get a failure, which is
-# actually acceptable as it warns us). But the case where we would copy
-# outdated data is much more insidious (such as wrong INSTALL
-# information or wrong git information) as it would be silent.
-# See: https://github.com/mesonbuild/meson/issues/10650
-# And: https://gitlab.gnome.org/GNOME/gimp/-/issues/7907
-# This is why we manually trigger, not only a reconfigure, but also a
-# rebuild of the main project before copying data around.
-
-# INSTALL file is generated at configure time.
-meson --reconfigure $MESON_SOURCE_ROOT
-# git-version.h is generated at build time.
-meson compile
-
-cp -f 'INSTALL' "${MESON_DIST_ROOT}"
-rm -f "${MESON_DIST_ROOT}/INSTALL.in"
-
-cp "$GIT_VERSION_H" "${MESON_DIST_ROOT}"