Use the exact current version in obtainMesonOutput

Currently this trims '0.48.0.dev1' to '0.48.0', and then requires exactly
that version in the generated meson.build for the test.

Just use the exact version.

Also only use a 'project(meson_version:)' constraint in the generated
project if a version is specified

Also remove unused grab_leading_numbers

mesonbuild/mesonlib.py

@@ -391,19 +391,6 @@ def detect_vcs(source_dir):
                 return vcs
     return None
 
-def grab_leading_numbers(vstr, strict=False):
-    result = []
-    for x in vstr.rstrip('.').split('.'):
-        try:
-            result.append(int(x))
-        except ValueError as e:
-            if strict:
-                msg = 'Invalid version to compare against: {!r}; only ' \
-                      'numeric digits separated by "." are allowed: ' + str(e)
-                raise MesonException(msg.format(vstr))
-            break
-    return result
-
 # a helper class which implements the same version ordering as RPM
 @functools.total_ordering
 class Version:

run_unittests.py

@@ -39,7 +39,7 @@ from mesonbuild.interpreter import Interpreter, ObjectHolder
 from mesonbuild.mesonlib import (
     is_windows, is_osx, is_cygwin, is_dragonflybsd, is_openbsd,
     windows_proof_rmtree, python_command, version_compare,
-    grab_leading_numbers, BuildDirLock
+    BuildDirLock
 )
 from mesonbuild.environment import detect_ninja
 from mesonbuild.mesonlib import MesonException, EnvironmentException
@@ -2663,7 +2663,7 @@ class FailureTests(BasePlatformTests):
         super().tearDown()
         windows_proof_rmtree(self.srcdir)
 
-    def assertMesonRaises(self, contents, match, extra_args=None, langs=None):
+    def assertMesonRaises(self, contents, match, extra_args=None, langs=None, meson_version=None):
         '''
         Assert that running meson configure on the specified @contents raises
         a error message matching regex @match.
@@ -2671,7 +2671,10 @@ class FailureTests(BasePlatformTests):
         if langs is None:
             langs = []
         with open(self.mbuild, 'w') as f:
-            f.write("project('failure test', 'c', 'cpp')\n")
+            f.write("project('failure test', 'c', 'cpp'")
+            if meson_version:
+                f.write(", meson_version: '{}'".format(meson_version))
+            f.write(")\n")
             for lang in langs:
                 f.write("add_languages('{}', required : false)\n".format(lang))
             f.write(contents)
@@ -2681,13 +2684,14 @@ class FailureTests(BasePlatformTests):
             # Must run in-process or we'll get a generic CalledProcessError
             self.init(self.srcdir, extra_args=extra_args, inprocess=True)
 
-    def obtainMesonOutput(self, contents, match, extra_args, langs, meson_version):
+    def obtainMesonOutput(self, contents, match, extra_args, langs, meson_version=None):
         if langs is None:
             langs = []
         with open(self.mbuild, 'w') as f:
-            core_version = '.'.join([str(component) for component in grab_leading_numbers(mesonbuild.coredata.version)])
-            meson_version = meson_version or core_version
-            f.write("project('output test', 'c', 'cpp', meson_version: '{}')\n".format(meson_version))
+            f.write("project('output test', 'c', 'cpp'")
+            if meson_version:
+                f.write(", meson_version: '{}'".format(meson_version))
+            f.write(")\n")
             for lang in langs:
                 f.write("add_languages('{}', required : false)\n".format(lang))
             f.write(contents)