[conf] Defining user_toolchain as list (#10729)

* Defining user_toolchains as list

* Simplified coded, added a couple of asserts

conan/tools/cmake/toolchain/blocks.py

@@ -542,9 +542,9 @@ class UserToolchain(Block):
 
     def context(self):
         # This is global [conf] injection of extra toolchain files
-        user_toolchain = self._conanfile.conf.get("tools.cmake.cmaketoolchain:user_toolchain")
-        toolchains = [user_toolchain.replace("\\", "/")] if user_toolchain else []
-        return {"paths": toolchains if toolchains else []}
+        user_toolchain = self._conanfile.conf.get("tools.cmake.cmaketoolchain:user_toolchain",
+                                                  default=[], check_type=list)
+        return {"paths": [ut.replace("\\", "/") for ut in user_toolchain]}
 
 
 class CMakeFlagsInitBlock(Block):

conans/model/conf.py

@@ -16,7 +16,7 @@
     "tools.cmake.cmaketoolchain:generator": "User defined CMake generator to use instead of default",
     "tools.cmake.cmaketoolchain:find_package_prefer_config": "Argument for the CMAKE_FIND_PACKAGE_PREFER_CONFIG",
     "tools.cmake.cmaketoolchain:toolchain_file": "Use other existing file rather than conan_toolchain.cmake one",
-    "tools.cmake.cmaketoolchain:user_toolchain": "Inject existing user toolchain at the beginning of conan_toolchain.cmake",
+    "tools.cmake.cmaketoolchain:user_toolchain": "Inject existing user toolchains at the beginning of conan_toolchain.cmake",
     "tools.cmake.cmaketoolchain:system_name": "Define CMAKE_SYSTEM_NAME in CMakeToolchain",
     "tools.cmake.cmaketoolchain:system_version": "Define CMAKE_SYSTEM_VERSION in CMakeToolchain",
     "tools.cmake.cmaketoolchain:system_processor": "Define CMAKE_SYSTEM_PROCESSOR in CMakeToolchain",
@@ -67,6 +67,10 @@ def __repr__(self):
 
     @property
     def value(self):
+        if self._value_type is list and _ConfVarPlaceHolder in self._value:
+            v = self._value[:]
+            v.remove(_ConfVarPlaceHolder)
+            return v
         return self._value
 
     def copy(self):

conans/test/functional/toolchains/cmake/test_cmake_toolchain.py

@@ -47,7 +47,7 @@ def test_cmake_toolchain_user_toolchain():
     client = TestClient(path_with_spaces=False)
     conanfile = GenConanfile().with_settings("os", "compiler", "build_type", "arch").\
         with_generator("CMakeToolchain")
-    save(client.cache.new_config_path, "tools.cmake.cmaketoolchain:user_toolchain=mytoolchain.cmake")
+    save(client.cache.new_config_path, "tools.cmake.cmaketoolchain:user_toolchain+=mytoolchain.cmake")
 
     client.save({"conanfile.py": conanfile})
     client.run("install .")
@@ -79,7 +79,7 @@ def package(self):
                 self.copy("*")
             def package_info(self):
                 f = os.path.join(self.package_folder, "mytoolchain.cmake")
-                self.conf_info["tools.cmake.cmaketoolchain:user_toolchain"] = f
+                self.conf_info.append("tools.cmake.cmaketoolchain:user_toolchain", f)
         """)
     client.save({"conanfile.py": conanfile,
                  "mytoolchain.cmake": 'message(STATUS "mytoolchain.cmake !!!running!!!")'})
@@ -136,7 +136,7 @@ def package(self):
                 self.copy("*")
             def package_info(self):
                 f = os.path.join(self.package_folder, "mytoolchain.cmake")
-                self.conf_info["tools.cmake.cmaketoolchain:user_toolchain"] = f
+                self.conf_info.append("tools.cmake.cmaketoolchain:user_toolchain", f)
         """)
     client.save({"conanfile.py": conanfile,
                  "mytoolchain.cmake": 'message(STATUS "mytoolchain1.cmake !!!running!!!")'})
@@ -147,26 +147,12 @@ def package_info(self):
 
     conanfile = textwrap.dedent("""
         from conans import ConanFile
-        from conan.tools.cmake import CMake, CMakeToolchain
+        from conan.tools.cmake import CMake
         class Pkg(ConanFile):
             settings = "os", "compiler", "arch", "build_type"
             exports_sources = "CMakeLists.txt"
             tool_requires = "toolchain1/0.1", "toolchain2/0.1"
-
-
-            def generate(self):
-                # Get the toolchains from "tools.cmake.cmaketoolchain:user_toolchain" conf at the
-                # tool_requires
-                user_toolchains = []
-                for dep in self.dependencies.direct_build.values():
-                    ut = dep.conf_info["tools.cmake.cmaketoolchain:user_toolchain"]
-                    if ut:
-                        user_toolchains.append(ut.replace('\\\\', '/'))
-
-                # Modify the context of the user_toolchain block
-                t = CMakeToolchain(self)
-                t.blocks["user_toolchain"].values["paths"] = user_toolchains
-                t.generate()
+            generators = "CMakeToolchain"
 
             def build(self):
                 cmake = CMake(self)

conans/test/integration/configuration/conf/test_conf_from_br.py

@@ -79,7 +79,7 @@ def test_declared_generators_get_conf():
         from conans import ConanFile
         class Pkg(ConanFile):
             def package_info(self):
-                self.conf_info["tools.cmake.cmaketoolchain:user_toolchain"] = "mytoolchain.cmake"
+                self.conf_info.append("tools.cmake.cmaketoolchain:user_toolchain", "mytoolchain.cmake")
         """)
     client.save({"conanfile.py": conanfile})
     client.run("create . mytool/1.0@")

conans/test/integration/toolchains/cmake/test_cmaketoolchain.py

@@ -52,7 +52,7 @@ def test_cross_build_user_toolchain():
         arch=armv8
         build_type=Release
         [conf]
-        tools.cmake.cmaketoolchain:user_toolchain=rpi_toolchain.cmake
+        tools.cmake.cmaketoolchain:user_toolchain+=rpi_toolchain.cmake
         """)
 
     client = TestClient(path_with_spaces=False)

conans/test/unittests/model/test_conf.py

@@ -200,6 +200,7 @@ def test_conf_get_check_type_and_default():
         zlib:user.company.check:shared=!
         zlib:user.company.check:shared_str="False"
         zlib:user.company.check:static_str=off
+        user.company.list:newnames+=myname
     """)
     c = ConfDefinition()
     c.loads(text)
@@ -210,10 +211,12 @@ def test_conf_get_check_type_and_default():
         assert "[conf] user.company.cpu:jobs must be a list-like object." in str(exc_info.value)
     # Check type does not affect to default value
     assert c.get("non:existing:conf", default=0, check_type=dict) == 0
+    assert c.get("zlib:user.company.check:shared") is None  # unset value
     assert c.get("zlib:user.company.check:shared_str") == '"False"'
     assert c.get("zlib:user.company.check:shared_str", check_type=bool) is False  # smart conversion
     assert c.get("zlib:user.company.check:static_str") == "off"
     assert c.get("zlib:user.company.check:static_str", check_type=bool) is False  # smart conversion
+    assert c.get("user.company.list:newnames") == ["myname"]  # Placeholder is removed
 
 
 def test_conf_pop():