Set the meson command to use when we know what it is

Instead of using fragile guessing to figure out how to invoke meson,
set the value when meson is run. Also rework how we pass of
meson_script_launcher to regenchecker.py -- it wasn't even being used

With this change, we only need to guess the meson path when running
the tests, and in that case:

1. If MESON_EXE is set in the env, we know how to run meson
   for project tests.
2. MESON_EXE is not set, which means we run the configure in-process
   for project tests and need to guess what meson to run, so either
   - meson.py is found next to run_tests.py, or
   - meson, meson.py, or meson.exe is in PATH

Otherwise, you can invoke meson in the following ways:

1. meson is installed, and mesonbuild is available in PYTHONPATH:
   - meson, meson.py, meson.exe from PATH
   - python3 -m mesonbuild.mesonmain
   - python3 /path/to/meson.py
   - meson is a shell wrapper to meson.real
2. meson is not installed, and is run from git:
   - Absolute path to meson.py
   - Relative path to meson.py
   - Symlink to meson.py

All these are tested in test_meson_commands.py, except meson.exe since
that involves building the meson msi and installing it.

1 files changed, 25 insertions, 39 deletions

diff --git a/run_unittests.py b/run_unittests.py
index 552769b..d6b2619 100755
--- a/run_unittests.py
+++ b/run_unittests.py
@@ -36,7 +36,7 @@ import mesonbuild.modules.gnome
 from mesonbuild.interpreter import ObjectHolder
 from mesonbuild.mesonlib import (
     is_windows, is_osx, is_cygwin, is_dragonflybsd,
-    windows_proof_rmtree, python_command, meson_command, version_compare,
+    windows_proof_rmtree, python_command, version_compare,
     BuildDirLock
 )
 from mesonbuild.environment import Environment, detect_ninja
@@ -44,9 +44,9 @@ from mesonbuild.mesonlib import MesonException, EnvironmentException
 from mesonbuild.dependencies import PkgConfigDependency, ExternalProgram
 import mesonbuild.modules.pkgconfig
 
-from run_tests import exe_suffix, get_fake_options
+from run_tests import exe_suffix, get_fake_options, get_meson_script
 from run_tests import get_builddir_target_args, get_backend_commands, Backend
-from run_tests import ensure_backend_detects_changes, run_configure, meson_exe
+from run_tests import ensure_backend_detects_changes, run_configure_inprocess
 from run_tests import should_run_linux_cross_tests
 
 
@@ -488,13 +488,13 @@ class BasePlatformTests(unittest.TestCase):
         # Get the backend
         # FIXME: Extract this from argv?
         self.backend = getattr(Backend, os.environ.get('MESON_UNIT_TEST_BACKEND', 'ninja'))
-        self.meson_mainfile = os.path.join(src_root, 'meson.py')
         self.meson_args = ['--backend=' + self.backend.name]
         self.meson_cross_file = None
-        self.meson_command = meson_command + self.meson_args
-        self.mconf_command = meson_command + ['configure']
-        self.mintro_command = meson_command + ['introspect']
-        self.wrap_command = meson_command + ['wrap']
+        self.meson_command = python_command + [get_meson_script()]
+        self.setup_command = self.meson_command + self.meson_args
+        self.mconf_command = self.meson_command + ['configure']
+        self.mintro_command = self.meson_command + ['introspect']
+        self.wrap_command = self.meson_command + ['wrap']
         # Backend-specific build commands
         self.build_command, self.clean_command, self.test_command, self.install_command, \
             self.uninstall_command = get_backend_commands(self.backend)
@@ -521,7 +521,7 @@ class BasePlatformTests(unittest.TestCase):
         self.logdir = os.path.join(self.builddir, 'meson-logs')
         self.installdir = os.path.join(self.builddir, 'install')
         self.distdir = os.path.join(self.builddir, 'meson-dist')
-        self.mtest_command = meson_command + ['test', '-C', self.builddir]
+        self.mtest_command = self.meson_command + ['test', '-C', self.builddir]
         self.builddirs.append(self.builddir)
 
     def new_builddir(self):
@@ -581,7 +581,7 @@ class BasePlatformTests(unittest.TestCase):
         self.privatedir = os.path.join(self.builddir, 'meson-private')
         if inprocess:
             try:
-                (returncode, out, err) = run_configure(self.meson_mainfile, self.meson_args + args + extra_args)
+                (returncode, out, err) = run_configure_inprocess(self.meson_args + args + extra_args)
                 if 'MESON_SKIP_TEST' in out:
                     raise unittest.SkipTest('Project requested skipping.')
                 if returncode != 0:
@@ -601,7 +601,7 @@ class BasePlatformTests(unittest.TestCase):
                 mesonbuild.mlog.log_file = None
         else:
             try:
-                out = self._run(self.meson_command + args + extra_args)
+                out = self._run(self.setup_command + args + extra_args)
             except unittest.SkipTest:
                 raise unittest.SkipTest('Project requested skipping: ' + srcdir)
             except:
@@ -902,8 +902,7 @@ class AllPlatformTests(BasePlatformTests):
         https://github.com/mesonbuild/meson/issues/1355
         '''
         testdir = os.path.join(self.common_test_dir, '3 static')
-        env = Environment(testdir, self.builddir, self.meson_command,
-                          get_fake_options(self.prefix), [])
+        env = Environment(testdir, self.builddir, get_fake_options(self.prefix), [])
         cc = env.detect_c_compiler(False)
         static_linker = env.detect_static_linker(cc)
         if is_windows():
@@ -1184,8 +1183,7 @@ class AllPlatformTests(BasePlatformTests):
         if not is_windows():
             langs += [('objc', 'OBJC'), ('objcpp', 'OBJCXX')]
         testdir = os.path.join(self.unit_test_dir, '5 compiler detection')
-        env = Environment(testdir, self.builddir, self.meson_command,
-                          get_fake_options(self.prefix), [])
+        env = Environment(testdir, self.builddir, get_fake_options(self.prefix), [])
         for lang, evar in langs:
             # Detect with evar and do sanity checks on that
             if evar in os.environ:
@@ -1287,8 +1285,7 @@ class AllPlatformTests(BasePlatformTests):
     def test_always_prefer_c_compiler_for_asm(self):
         testdir = os.path.join(self.common_test_dir, '141 c cpp and asm')
         # Skip if building with MSVC
-        env = Environment(testdir, self.builddir, self.meson_command,
-                          get_fake_options(self.prefix), [])
+        env = Environment(testdir, self.builddir, get_fake_options(self.prefix), [])
         if env.detect_c_compiler(False).get_id() == 'msvc':
             raise unittest.SkipTest('MSVC can\'t compile assembly')
         self.init(testdir)
@@ -1546,8 +1543,7 @@ int main(int argc, char **argv) {
             self.assertPathExists(os.path.join(testdir, i))
 
     def detect_prebuild_env(self):
-        env = Environment('', self.builddir, self.meson_command,
-                          get_fake_options(self.prefix), [])
+        env = Environment('', self.builddir, get_fake_options(self.prefix), [])
         cc = env.detect_c_compiler(False)
         stlinker = env.detect_static_linker(cc)
         if mesonbuild.mesonlib.is_windows():
@@ -1715,8 +1711,7 @@ int main(int argc, char **argv) {
                                        '--libdir=' + libdir])
         # Find foo dependency
         os.environ['PKG_CONFIG_LIBDIR'] = self.privatedir
-        env = Environment(testdir, self.builddir, self.meson_command,
-                          get_fake_options(self.prefix), [])
+        env = Environment(testdir, self.builddir, get_fake_options(self.prefix), [])
         kwargs = {'required': True, 'silent': True}
         foo_dep = PkgConfigDependency('libfoo', env, kwargs)
         # Ensure link_args are properly quoted
@@ -1849,16 +1844,16 @@ int main(int argc, char **argv) {
         for lang in ('c', 'cpp'):
             for type in ('executable', 'library'):
                 with tempfile.TemporaryDirectory() as tmpdir:
-                    self._run(meson_command + ['init', '--language', lang, '--type', type],
+                    self._run(self.meson_command + ['init', '--language', lang, '--type', type],
                               workdir=tmpdir)
-                    self._run(self.meson_command + ['--backend=ninja', 'builddir'],
+                    self._run(self.setup_command + ['--backend=ninja', 'builddir'],
                               workdir=tmpdir)
                     self._run(ninja,
                               workdir=os.path.join(tmpdir, 'builddir'))
             with tempfile.TemporaryDirectory() as tmpdir:
                 with open(os.path.join(tmpdir, 'foo.' + lang), 'w') as f:
                     f.write('int main() {}')
-                self._run(meson_command + ['init', '-b'], workdir=tmpdir)
+                self._run(self.meson_command + ['init', '-b'], workdir=tmpdir)
 
     # The test uses mocking and thus requires that
     # the current process is the one to run the Meson steps.
@@ -1983,8 +1978,7 @@ recommended as it can lead to undefined behaviour on some platforms''')
         testdirbase = os.path.join(self.unit_test_dir, '26 guessed linker dependencies')
         testdirlib = os.path.join(testdirbase, 'lib')
         extra_args = None
-        env = Environment(testdirlib, self.builddir, self.meson_command,
-                          get_fake_options(self.prefix), [])
+        env = Environment(testdirlib, self.builddir, get_fake_options(self.prefix), [])
         if env.detect_c_compiler(False).get_id() != 'msvc':
             # static libraries are not linkable with -l with msvc because meson installs them
             # as .a files which unix_args_to_native will not know as it expects libraries to use
@@ -2146,9 +2140,6 @@ class FailureTests(BasePlatformTests):
         Assert that running meson configure on the specified @contents raises
         a error message matching regex @match.
         '''
-        if meson_exe is not None:
-            # Because the exception happens in a different process.
-            raise unittest.SkipTest('Can not test assert raise tests with an external Meson command.')
         if langs is None:
             langs = []
         with open(self.mbuild, 'w') as f:
@@ -2283,8 +2274,7 @@ class FailureTests(BasePlatformTests):
         '''
         Test that when we can't detect objc or objcpp, we fail gracefully.
         '''
-        env = Environment('', self.builddir, self.meson_command,
-                          get_fake_options(self.prefix), [])
+        env = Environment('', self.builddir, get_fake_options(self.prefix), [])
         try:
             env.detect_objc_compiler(False)
             env.detect_objcpp_compiler(False)
@@ -2393,8 +2383,7 @@ class WindowsTests(BasePlatformTests):
         ExternalLibraryHolder from build files.
         '''
         testdir = os.path.join(self.platform_test_dir, '1 basic')
-        env = Environment(testdir, self.builddir, self.meson_command,
-                          get_fake_options(self.prefix), [])
+        env = Environment(testdir, self.builddir, get_fake_options(self.prefix), [])
         cc = env.detect_c_compiler(False)
         if cc.id != 'msvc':
             raise unittest.SkipTest('Not using MSVC')
@@ -2464,8 +2453,7 @@ class LinuxlikeTests(BasePlatformTests):
         '''
         testdir = os.path.join(self.common_test_dir, '51 pkgconfig-gen')
         self.init(testdir)
-        env = Environment(testdir, self.builddir, self.meson_command,
-                          get_fake_options(self.prefix), [])
+        env = Environment(testdir, self.builddir, get_fake_options(self.prefix), [])
         kwargs = {'required': True, 'silent': True}
         os.environ['PKG_CONFIG_LIBDIR'] = self.privatedir
         foo_dep = PkgConfigDependency('libfoo', env, kwargs)
@@ -2715,8 +2703,7 @@ class LinuxlikeTests(BasePlatformTests):
         an ordinary test because it requires passing options to meson.
         '''
         testdir = os.path.join(self.common_test_dir, '1 trivial')
-        env = Environment(testdir, self.builddir, self.meson_command,
-                          get_fake_options(self.prefix), [])
+        env = Environment(testdir, self.builddir, get_fake_options(self.prefix), [])
         cc = env.detect_c_compiler(False)
         self._test_stds_impl(testdir, cc, 'c')
 
@@ -2726,8 +2713,7 @@ class LinuxlikeTests(BasePlatformTests):
         be an ordinary test because it requires passing options to meson.
         '''
         testdir = os.path.join(self.common_test_dir, '2 cpp')
-        env = Environment(testdir, self.builddir, self.meson_command,
-                          get_fake_options(self.prefix), [])
+        env = Environment(testdir, self.builddir, get_fake_options(self.prefix), [])
         cpp = env.detect_cpp_compiler(False)
         self._test_stds_impl(testdir, cpp, 'cpp')