compilers: use correct version comparison for openbsd libraries

It should *be* a version comparison. We are guaranteed to get a
two-element version number, which also parses as a float but a float
doesn't correctly handle version sorting when the second component
differs in number of digits.

The standard way to handle this is by comparing tuples such that each
component is an integer. Do so here.

Fixes #12195

Co-authored-by: George Koehler <xkernigh@netscape.net>
(for unittests)

mesonbuild/compilers/mixins/clike.py

@@ -1084,6 +1084,10 @@ class CLikeCompiler(Compiler):
 
     @staticmethod
     def _sort_shlibs_openbsd(libs: T.List[str]) -> T.List[str]:
+        def tuple_key(x: str) -> T.Tuple[int, ...]:
+            ver = x.rsplit('.so.', maxsplit=1)[1]
+            return tuple(int(i) for i in ver.split('.'))
+
         filtered: T.List[str] = []
         for lib in libs:
             # Validate file as a shared library of type libfoo.so.X.Y
@@ -1091,12 +1095,11 @@ class CLikeCompiler(Compiler):
             if len(ret) != 2:
                 continue
             try:
-                float(ret[1])
+                tuple(int(i) for i in ret[1].split('.'))
             except ValueError:
                 continue
             filtered.append(lib)
-        float_cmp = lambda x: float(x.rsplit('.so.', maxsplit=1)[1])
-        return sorted(filtered, key=float_cmp, reverse=True)
+        return sorted(filtered, key=tuple_key, reverse=True)
 
     @classmethod
     def _get_trials_from_pattern(cls, pattern: str, directory: str, libname: str) -> T.List[Path]:

unittests/internaltests.py

@@ -549,11 +549,14 @@ class InternalTests(unittest.TestCase):
         if platform != 'openbsd':
             return
         with tempfile.TemporaryDirectory() as tmpdir:
-            for i in ['libfoo.so.6.0', 'libfoo.so.5.0', 'libfoo.so.54.0', 'libfoo.so.66a.0b', 'libfoo.so.70.0.so.1']:
+            for i in ['libfoo.so.6.0', 'libfoo.so.5.0', 'libfoo.so.54.0', 'libfoo.so.66a.0b', 'libfoo.so.70.0.so.1',
+                      'libbar.so.7.10', 'libbar.so.7.9', 'libbar.so.7.9.3']:
                 libpath = Path(tmpdir) / i
                 libpath.write_text('', encoding='utf-8')
             found = cc._find_library_real('foo', env, [tmpdir], '', LibType.PREFER_SHARED, lib_prefix_warning=True)
             self.assertEqual(os.path.basename(found[0]), 'libfoo.so.54.0')
+            found = cc._find_library_real('bar', env, [tmpdir], '', LibType.PREFER_SHARED, lib_prefix_warning=True)
+            self.assertEqual(os.path.basename(found[0]), 'libbar.so.7.10')
 
     def test_find_library_patterns(self):
         '''