Properly error out when cross file is missing a compiler.

cross/noexes.txt

@@ -0,0 +1,9 @@
+# A cross file that is missing compilers must lead to
+# an error.
+[binaries]
+
+[target_machine]
+system = 'linux'
+cpu_family = 'mips'
+cpu = 'mips'
+endian = 'little'

cross/ubuntu-faketarget.txt

@@ -1,13 +0,0 @@
-# This is a setup for compiling a program that runs natively
-# but produces output that runs on a different platform.
-# That is either a cross compiler or something like binutils.
-
-# We don't need to specify any properties or compilers,
-# for we use the native ones and can run the resulting
-# binaries directly.
-
-[target_machine]
-system = 'linux'
-cpu_family = 'mips'
-cpu = 'mips'
-endian = 'little'

mesonbuild/compilers/detect.py

@@ -240,8 +240,9 @@ def _get_compilers(env: 'Environment', lang: str, for_machine: MachineChoice) ->
         # Return value has to be a list of compiler 'choices'
         compilers = [comp]
     else:
-        if not env.machines.matches_build_machine(for_machine):
-            raise EnvironmentException(f'{lang!r} compiler binary not defined in cross or native file')
+        # Cross compilers must NEVER EVER be taken from envvars.
+        if env.is_cross_build() and for_machine == MachineChoice.HOST:
+            raise EnvironmentException(f'{lang!r} compiler binary not defined in a cross file')
         compilers = [[x] for x in defaults[lang]]
         ccache = BinaryTable.detect_compiler_cache()
 

test cases/common/10 man install/meson.build

@@ -1,4 +1,4 @@
-project('man install', 'c')
+project('man install')
 m1 = install_man('foo.1')
 m2 = install_man('bar.2')
 m3 = install_man('foo.fr.1', locale: 'fr')

unittests/allplatformstests.py

@@ -3597,6 +3597,8 @@ class AllPlatformTests(BasePlatformTests):
         machinefile = os.path.join(self.builddir, 'machine.txt')
         with open(machinefile, 'w', encoding='utf-8') as f:
             f.write(textwrap.dedent('''
+                [binaries]
+                c = 'cc'
                 [properties]
                 c_stdlib = 'mylibc'
                 '''))

unittests/linuxcrosstests.py

@@ -125,6 +125,14 @@ class LinuxCrossArmTests(BaseLinuxCrossTests):
         self.run_tests()
         self.assertPathExists(stamp_file)
 
+    def test_missing_compilers(self):
+        '''
+        Requesting a compiler that is not in the cross file must be an error.
+        '''
+        testdir = os.path.join(self.common_test_dir, '1 trivial')
+        self.meson_cross_files = [os.path.join(self.src_root, 'cross', 'noexes.txt')]
+        with self.assertRaises(subprocess.CalledProcessError, msg='compiler binary not defined in a cross file'):
+            self.init(testdir)
 
 def should_run_cross_mingw_tests():
     return shutil.which('x86_64-w64-mingw32-gcc') and not (is_windows() or is_cygwin())

unittests/machinefiletests.py

@@ -740,7 +740,7 @@ class CrossFileTests(BasePlatformTests):
                     self.init(testdir, extra_args=['--cross-file=' + name], inprocess=True)
                     self.wipe()
 
-    def helper_create_cross_file(self, values):
+    def helper_create_cross_file(self, values, *, add_fake_compilers=True):
         """Create a config file as a temporary file.
 
         values should be a nested dictionary structure of {section: {key:
@@ -748,6 +748,13 @@ class CrossFileTests(BasePlatformTests):
         """
         filename = os.path.join(self.builddir, f'generated{self.current_config}.config')
         self.current_config += 1
+        if add_fake_compilers:
+            if is_windows() and shutil.which('cl'):
+                base = {'binaries': {'c': 'cl', 'cpp': 'cl'}}
+            else:
+                base = {'binaries': {'c': 'cc', 'cpp': 'c++'}}
+            base.update(values)
+            values = base
         with open(filename, 'wt', encoding='utf-8') as f:
             for section, entries in values.items():
                 f.write(f'[{section}]\n')