[MesonToolchain] Binaries c, cpp and ld (added recently) can be lists

conan/tools/meson/toolchain.py

@@ -39,8 +39,9 @@ class MesonToolchain(object):
     {% endfor %}
 
     [binaries]
-    {% if c %}c = '{{c}}'{% endif %}
-    {% if cpp %}cpp = '{{cpp}}'{% endif %}
+    {% if c %}c = {{c}}{% endif %}
+    {% if cpp %}cpp = {{cpp}}{% endif %}
+    {% if ld %}ld = {{ld}}{% endif %}
     {% if is_apple_system %}
     {% if objc %}objc = '{{objc}}'{% endif %}
     {% if objcpp %}objcpp = '{{objcpp}}'{% endif %}
@@ -190,13 +191,17 @@ def __init__(self, conanfile, backend=None):
         self.c = compilers_by_conf.get("c") or build_env.get("CC") or default_comp
         #: Defines the Meson ``cpp`` variable. Defaulted to ``CXX`` build environment value
         self.cpp = compilers_by_conf.get("cpp") or build_env.get("CXX") or default_comp_cpp
+        #: Defines the Meson ``ld`` variable. Defaulted to ``LD`` build environment value
+        self.ld = build_env.get("LD")
         # FIXME: Should we use the new tools.build:compiler_executables and avoid buildenv?
-        #: Defines the Meson ``c_ld`` variable. Defaulted to ``CC_LD`` or ``LD`` build
+        # Issue related: https://github.com/mesonbuild/meson/issues/6442
+        # PR related: https://github.com/mesonbuild/meson/pull/6457
+        #: Defines the Meson ``c_ld`` variable. Defaulted to ``CC_LD``
         #: environment value
-        self.c_ld = build_env.get("CC_LD") or build_env.get("LD")
-        #: Defines the Meson ``cpp_ld`` variable. Defaulted to ``CXX_LD`` or ``LD`` build
+        self.c_ld = build_env.get("CC_LD")
+        #: Defines the Meson ``cpp_ld`` variable. Defaulted to ``CXX_LD``
         #: environment value
-        self.cpp_ld = build_env.get("CXX_LD") or build_env.get("LD")
+        self.cpp_ld = build_env.get("CXX_LD")
         #: Defines the Meson ``ar`` variable. Defaulted to ``AR`` build environment value
         self.ar = build_env.get("AR")
         #: Defines the Meson ``strip`` variable. Defaulted to ``STRIP`` build environment value
@@ -354,6 +359,12 @@ def _filter_list_empty_fields(v):
         return list(filter(bool, v))
 
     def _context(self):
+        def _sanitize_format(v):
+            if v is None or isinstance(v, list):
+                return v
+            ret = [x.strip() for x in v.split() if x]
+            return f"'{ret[0]}'" if len(ret) == 1 else ret
+
         apple_flags = self.apple_isysroot_flag + self.apple_arch_flag + self.apple_min_version_flag
         extra_flags = self._get_extra_flags()
 
@@ -380,11 +391,11 @@ def _context(self):
             # https://mesonbuild.com/Machine-files.html#project-specific-options
             "project_options": {k: to_meson_value(v) for k, v in self.project_options.items()},
             # https://mesonbuild.com/Builtin-options.html#directories
-            # TODO : we don't manage paths like libdir here (yet?)
             # https://mesonbuild.com/Machine-files.html#binaries
             # https://mesonbuild.com/Reference-tables.html#compiler-and-linker-selection-variables
-            "c": self.c,
-            "cpp": self.cpp,
+            "c": _sanitize_format(self.c),
+            "cpp": _sanitize_format(self.cpp),
+            "ld": _sanitize_format(self.ld),
             "objc": self.objc,
             "objcpp": self.objcpp,
             "c_ld": self.c_ld,

conans/test/integration/toolchains/meson/test_mesontoolchain.py

@@ -4,6 +4,7 @@
 import pytest
 
 from conan.tools.meson import MesonToolchain
+from conans.test.assets.genconanfile import GenConanfile
 from conans.test.utils.tools import TestClient
 
 
@@ -205,3 +206,80 @@ def test_clang_cl_vscrt(build_type, runtime, vscrt):
     t.run("install . -pr:h=profile -pr:b=profile")
     content = t.load(MesonToolchain.native_filename)
     assert f"b_vscrt = '{vscrt}'" in content
+
+
+def test_env_vars_from_build_require():
+    conanfile = textwrap.dedent("""
+    from conan import ConanFile
+    import os
+
+    class HelloConan(ConanFile):
+        name = 'hello_compiler'
+        version = '1.0'
+        def package_info(self):
+            self.buildenv_info.define("CC", "CC_VALUE")
+            self.buildenv_info.define("CC_LD", "CC_LD_VALUE")
+            self.buildenv_info.define("CXX", "CXX_VALUE")
+            self.buildenv_info.define("CXX_LD", "CXX_LD_VALUE")
+            self.buildenv_info.define("AR", "AR_VALUE")
+            self.buildenv_info.define("STRIP", "STRIP_VALUE")
+            self.buildenv_info.define("AS", "AS_VALUE")
+            self.buildenv_info.define("WINDRES", "WINDRES_VALUE")
+            self.buildenv_info.define("PKG_CONFIG", "PKG_CONFIG_VALUE")
+            self.buildenv_info.define("LD", "LD_VALUE")
+    """)
+    client = TestClient()
+    client.save({"conanfile.py": conanfile})
+    client.run("create .")
+
+    conanfile = textwrap.dedent("""
+    from conan import ConanFile
+    class HelloConan(ConanFile):
+        name = 'consumer'
+        version = '1.0'
+        generators = "MesonToolchain"
+        settings = "os", "arch", "compiler", "build_type"
+
+        def requirements(self):
+            self.tool_requires("hello_compiler/1.0", )
+    """)
+    # Now, let's check how all the build env variables are applied at consumer side
+    client.save({"conanfile.py": conanfile})
+    client.run("install . -pr:h=default -pr:b=default")
+    content = client.load("conan_meson_native.ini")
+    assert "c = 'CC_VALUE'" in content
+    assert "cpp = 'CXX_VALUE'" in content
+    assert "ld = 'LD_VALUE'" in content
+    assert "c_ld = 'CC_LD_VALUE'" in content
+    assert "cpp_ld = 'CXX_LD_VALUE'" in content
+    assert "ar = 'AR_VALUE'" in content
+    assert "strip = 'STRIP_VALUE'" in content
+    assert "as = 'AS_VALUE'" in content
+    assert "windres = 'WINDRES_VALUE'" in content
+    assert "pkgconfig = 'PKG_CONFIG_VALUE'" in content
+
+
+def test_check_c_cpp_ld_list_formats():
+    # Issue related: https://github.com/conan-io/conan/issues/14028
+    profile = textwrap.dedent("""
+       [settings]
+       os=Windows
+       arch=x86_64
+       compiler=gcc
+       compiler.version=9
+       compiler.cppstd=17
+       compiler.libcxx=libstdc++11
+       build_type=Release
+       [buildenv]
+       CC=aarch64-poky-linux-gcc  -mcpu=cortex-a53 -march=armv8-a+crc+crypto
+       CXX=aarch64-poky-linux-g++  -mcpu=cortex-a53 -march=armv8-a+crc+crypto
+       LD=aarch64-poky-linux-ld  --sysroot=/opt/sysroots/cortexa53-crypto-poky-linux
+       """)
+    t = TestClient()
+    t.save({"conanfile.txt": "[generators]\nMesonToolchain",
+            "profile": profile})
+    t.run("install . -pr:h=profile -pr:b=profile")
+    content = t.load(MesonToolchain.native_filename)
+    assert "c = ['aarch64-poky-linux-gcc', '-mcpu=cortex-a53', '-march=armv8-a+crc+crypto']" in content
+    assert "cpp = ['aarch64-poky-linux-g++', '-mcpu=cortex-a53', '-march=armv8-a+crc+crypto']" in content
+    assert "ld = ['aarch64-poky-linux-ld', '--sysroot=/opt/sysroots/cortexa53-crypto-poky-linux']" in content