build: use the unified pickle loader to handle more edge cases

We have divergent implementations of loading a pickled *.dat file. The
Build class loader has a better error message. But the generic loader
handles TypeError and ModuleNotFoundError. Merge the implementations,
and use it for Build as well.

Fixes #11051

1 files changed, 8 insertions, 3 deletions

diff --git a/mesonbuild/utils/universal.py b/mesonbuild/utils/universal.py
index 570edd6..b1a301a 100644
--- a/mesonbuild/utils/universal.py
+++ b/mesonbuild/utils/universal.py
@@ -2289,16 +2289,21 @@ def pickle_load(filename: str, object_name: str, object_type: T.Type) -> T.Any:
     except (pickle.UnpicklingError, EOFError):
         raise MesonException(load_fail_msg)
     except (TypeError, ModuleNotFoundError, AttributeError):
+        build_dir = os.path.dirname(os.path.dirname(filename))
         raise MesonException(
             f"{object_name} file {filename!r} references functions or classes that don't "
             "exist. This probably means that it was generated with an old "
-            "version of meson.")
+            "version of meson. Try running from the source directory "
+            f'meson setup {build_dir} --wipe')
     if not isinstance(obj, object_type):
         raise MesonException(load_fail_msg)
     from ..coredata import version as coredata_version
     from ..coredata import major_versions_differ, MesonVersionMismatchException
-    if major_versions_differ(obj.version, coredata_version):
-        raise MesonVersionMismatchException(obj.version, coredata_version)
+    version = getattr(obj, 'version', None)
+    if version is None:
+        version = obj.environment.coredata.version
+    if major_versions_differ(version, coredata_version):
+        raise MesonVersionMismatchException(version, coredata_version)
     return obj