build: use user-supplied CROSS_COMPILE in compiler check

The compiler check used the arch default CROSS_COMPILE. When the
user passed a different one on the command line, the check failed
even though the right compiler was installed.

Pass the user-supplied CROSS_COMPILE to is_supported() and keep the
ContainerRuntime lru_cache clean by not including it in the cache key.

Fixes: 472ce8f ("runtime: null: check if compiler exists on host")
Fixes: 9f457b8 ("build: raise CompilerNotFoundError for null runtime")
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>

Author: roxell

test/test_build.py

@@ -901,6 +901,19 @@ def test_null_runtime_compiler_not_found(self, linux, mocker):
         with pytest.raises(tuxmake.exceptions.CompilerNotFoundError):
             Build(tree=linux, target_arch="arc", toolchain="clang")
 
+    def test_null_runtime_cross_compile_override(self, linux, mocker):
+        which = mocker.patch(
+            "shutil.which", return_value="/usr/bin/arm-linux-gnueabi-gcc"
+        )
+        build = Build(
+            tree=linux,
+            target_arch="arm",
+            toolchain="gcc-15",
+            make_variables={"CROSS_COMPILE": "arm-linux-gnueabi-"},
+        )
+        assert build.runtime.name == "null"
+        which.assert_called_with("arm-linux-gnueabi-gcc")
+
 
 class TestDebug:
     def test_no_debug_without_debug_options(self, linux, capfd):
@@ -1153,7 +1166,8 @@ def test_compression_none(self, linux):
 
 
 class TestCustomCrossCompile:
-    def test_CROSS_COMPILE(self, linux, Popen):
+    def test_CROSS_COMPILE(self, linux, Popen, mocker):
+        mocker.patch("shutil.which", return_value="/usr/bin/foo-gcc")
         build = Build(
             tree=linux, target_arch="arm64", make_variables={"CROSS_COMPILE": "foo-"}
         )

tuxmake/build.py

@@ -246,9 +246,14 @@ def __init__(
         self.runtime = Runtime.get(runtime)
         self.runtime.set_image(get_image(self))
 
-        if not self.runtime.is_supported(self.target_arch, self.toolchain):
+        cross_compile = self.make_variables.get("CROSS_COMPILE")
+        if not self.runtime.is_supported(
+            self.target_arch, self.toolchain, cross_compile=cross_compile
+        ):
             if self.runtime.name == "null":
-                compiler = self.toolchain.compiler(self.target_arch)
+                compiler = self.toolchain.compiler(
+                    self.target_arch, cross_compile=cross_compile
+                )
                 raise CompilerNotFoundError(compiler)
             raise UnsupportedArchitectureToolchainCombination(
                 f"{self.target_arch}/{self.toolchain}"

tuxmake/runtime.py

@@ -160,7 +160,7 @@ def set_group(self, group):
         """
         self.__group__ = group
 
-    def is_supported(self, arch, toolchain):
+    def is_supported(self, arch, toolchain, cross_compile=None):
         return True
 
     @property
@@ -362,8 +362,8 @@ def run_cmd(
 class NullRuntime(Runtime):
     name = "null"
 
-    def is_supported(self, arch, toolchain):
-        compiler = toolchain.compiler(arch)
+    def is_supported(self, arch, toolchain, cross_compile=None):
+        compiler = toolchain.compiler(arch, cross_compile=cross_compile)
         return shutil.which(compiler) is not None
 
 
@@ -467,8 +467,11 @@ def volumes(self):
     def add_volume(self, source, dest=None, ro=False, device=False):
         self.volumes.append((source, dest or source, ro, device))
 
+    def is_supported(self, arch, toolchain, cross_compile=None):
+        return self.__is_supported_cached(arch, toolchain)
+
     @lru_cache(None)
-    def is_supported(self, arch, toolchain):
+    def __is_supported_cached(self, arch, toolchain):
         image_name = arch.get_image(toolchain) or toolchain.get_image(arch)
         image = self.toolchain_images_map.get(image_name)
         if toolchain.name.startswith("korg-gcc"):