interpreter: handle build_target.darwin_versions being unset vs being…

… explicitly []

Which has (perhaps unintentionally) different behavior. When unset the
value of darwin_versions will be `(so_version, so_version)`, when it's
set to `[]` then no values will be used even if so_version is set.

Fixes: #12604

mesonbuild/build.py

@@ -2364,10 +2364,14 @@ def process_kwargs(self, kwargs):
                 # number of the version by default.
                 self.soversion = self.ltversion.split('.')[0]
             # macOS, iOS and tvOS dylib compatibility_version and current_version
-            self.darwin_versions = T.cast('T.Optional[T.Tuple[str, str]]', kwargs.get('darwin_versions'))
-            if self.darwin_versions is None and self.soversion is not None:
+            d = T.cast('T.Union[None, Literal[False], T.Tuple[str, str]]', kwargs.get('darwin_versions'))
+            if d is None and self.soversion is not None:
                 # If unspecified, pick the soversion
                 self.darwin_versions = (self.soversion, self.soversion)
+            elif d is False:
+                self.darwin_versions = None
+            else:
+                self.darwin_versions = d
 
         # Visual Studio module-definitions file
         self.process_vs_module_defs_kw(kwargs)

mesonbuild/interpreter/kwargs.py

@@ -397,7 +397,7 @@ class StaticLibrary(_BuildTarget, _StaticLibMixin, _LibraryMixin):
 
 class _SharedLibMixin(TypedDict):
 
-    darwin_versions: T.Optional[T.Tuple[str, str]]
+    darwin_versions: T.Union[None, Literal[False], T.Tuple[str, str]]
     soversion: T.Optional[str]
     version: T.Optional[str]
     vs_module_defs: T.Optional[T.Union[str, File, build.CustomTarget, build.CustomTargetIndex]]

mesonbuild/interpreter/type_checking.py

@@ -680,9 +680,14 @@ def _validate_darwin_versions(darwin_versions: T.List[T.Union[str, int]]) -> T.O
     return None
 
 
-def _convert_darwin_versions(val: T.List[T.Union[str, int]]) -> T.Optional[T.Tuple[str, str]]:
-    if not val:
+def _convert_darwin_versions(val: T.List[T.Union[str, int]]) -> T.Union[None, Literal[False], T.Tuple[str, str]]:
+    # Returns None if unset, but False if an empty list is passed, which
+    # annoyingly have different behavior. False means do no use soversion, while
+    # None means do use it.
+    if None in val:
         return None
+    if not val:
+        return False
     elif len(val) == 1:
         v = str(val[0])
         return (v, v)
@@ -691,8 +696,8 @@ def _convert_darwin_versions(val: T.List[T.Union[str, int]]) -> T.Optional[T.Tup
 
 _DARWIN_VERSIONS_KW: KwargInfo[T.List[T.Union[str, int]]] = KwargInfo(
     'darwin_versions',
-    ContainerTypeInfo(list, (str, int)),
-    default=[],
+    ContainerTypeInfo(list, (str, int, NoneType)),
+    default=[None],
     listify=True,
     validator=_validate_darwin_versions,
     convertor=_convert_darwin_versions,

test cases/common/4 shared/meson.build

@@ -1,6 +1,6 @@
 project('shared library test', 'c', default_options : ['default_library=shared'])
 lib = shared_library('mylib', 'libfile.c')
-build_target('mylib2', 'libfile.c', target_type: 'shared_library')
+build_target('mylib2', 'libfile.c', target_type: 'shared_library', soversion : 'invalid_darwin_version', darwin_versions: [])
 
 has_not_changed = false
 if is_disabler(lib)