build: Assert extension-tool version is bumped alongside gnome-shell

I always forget to keep the extension-tool version number in sync when
doing a new release. Given that it's unlikely that I'll do much better
in the future by myself, make distcheck fail when the versions don't
match.

https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1076

meson.build

@@ -244,12 +244,17 @@ libgvc = subproject('gvc',
 libgvc_gir = libgvc.get_variable('libgvc_gir')
 
 if get_option('extensions_tool')
-  subproject('extensions-tool',
+  extension_tool = subproject('extensions-tool',
     default_options: [
       'man=@0@'.format(get_option('man')),
       'package_name=@0@'.format(meson.project_name()),
     ]
   )
+
+  extension_tool_version = extension_tool.get_variable('package_version')
+  assert(extension_tool_version == meson.project_version(),
+    'extension-tool version does not match project version'
+  )
 endif
 
 

subprojects/extensions-tool/meson.build

@@ -10,6 +10,7 @@ gnome = import('gnome')
 i18n  = import('i18n')
 
 package_name = get_option('package_name')
+package_version = meson.project_version()
 prefix = get_option('prefix')
 
 bindir = join_paths(prefix, get_option('bindir'))