allow gnuinstall dirs local flow (#16214)

conan/tools/cmake/toolchain/blocks.py

@@ -969,11 +969,10 @@ class OutputDirsBlock(Block):
 
     @property
     def template(self):
-        if not self._conanfile.package_folder:
-            return ""
-
         return textwrap.dedent("""
+           {% if package_folder %}
            set(CMAKE_INSTALL_PREFIX "{{package_folder}}")
+           {% endif %}
            {% if default_bin %}
            set(CMAKE_INSTALL_BINDIR "{{default_bin}}")
            set(CMAKE_INSTALL_SBINDIR "{{default_bin}}")
@@ -998,9 +997,8 @@ def _get_cpp_info_value(self, name):
         return elements[0] if elements else None
 
     def context(self):
-        if not self._conanfile.package_folder:
-            return {}
-        return {"package_folder": self._conanfile.package_folder.replace("\\", "/"),
+        pf = self._conanfile.package_folder
+        return {"package_folder": pf.replace("\\", "/") if pf else None,
                 "default_bin": self._get_cpp_info_value("bindirs"),
                 "default_lib": self._get_cpp_info_value("libdirs"),
                 "default_include": self._get_cpp_info_value("includedirs"),

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

@@ -1438,3 +1438,78 @@ def layout(self):
     assert os.path.isabs(user_presets["include"][0])
     presets = json.loads(c.load(user_presets["include"][0]))
     assert os.path.isabs(presets["configurePresets"][0]["toolchainFile"])
+
+
+def test_output_dirs_gnudirs_local_default():
+    # https://github.com/conan-io/conan/issues/14733
+    c = TestClient()
+    conanfile = textwrap.dedent("""
+        from conan import ConanFile
+        from conan.tools.cmake import cmake_layout
+        from conan.tools.files import load
+
+        class Conan(ConanFile):
+            name = "pkg"
+            version = "0.1"
+            settings = "os", "arch", "compiler", "build_type"
+            generators = "CMakeToolchain"
+            def build(self):
+                tc = load(self, "conan_toolchain.cmake")
+                self.output.info(tc)
+        """)
+    c.save({"conanfile.py": conanfile})
+    c.run("create .")
+
+    def _assert_install(out):
+        assert 'set(CMAKE_INSTALL_BINDIR "bin")' in out
+        assert 'set(CMAKE_INSTALL_SBINDIR "bin")' in out
+        assert 'set(CMAKE_INSTALL_LIBEXECDIR "bin")' in out
+        assert 'set(CMAKE_INSTALL_LIBDIR "lib")' in out
+        assert 'set(CMAKE_INSTALL_INCLUDEDIR "include")' in out
+
+    _assert_install(c.out)
+    assert "CMAKE_INSTALL_PREFIX" in c.out
+
+    c.run("build .")
+    _assert_install(c.out)
+    assert "CMAKE_INSTALL_PREFIX" not in c.out
+
+
+def test_output_dirs_gnudirs_local_custom():
+    # https://github.com/conan-io/conan/issues/14733
+    c = TestClient()
+    conanfile = textwrap.dedent("""
+        from conan import ConanFile
+        from conan.tools.cmake import cmake_layout
+        from conan.tools.files import load
+
+        class Conan(ConanFile):
+            name = "pkg"
+            version = "0.1"
+            settings = "os", "arch", "compiler", "build_type"
+            generators = "CMakeToolchain"
+            def layout(self):
+                self.cpp.package.bindirs = ["mybindir"]
+                self.cpp.package.includedirs = ["myincludedir"]
+                self.cpp.package.libdirs = ["mylibdir"]
+
+            def build(self):
+                tc = load(self, "conan_toolchain.cmake")
+                self.output.info(tc)
+        """)
+    c.save({"conanfile.py": conanfile})
+    c.run("create .")
+
+    def _assert_install(out):
+        assert 'set(CMAKE_INSTALL_BINDIR "mybindir")' in out
+        assert 'set(CMAKE_INSTALL_SBINDIR "mybindir")' in out
+        assert 'set(CMAKE_INSTALL_LIBEXECDIR "mybindir")' in out
+        assert 'set(CMAKE_INSTALL_LIBDIR "mylibdir")' in out
+        assert 'set(CMAKE_INSTALL_INCLUDEDIR "myincludedir")' in out
+
+    _assert_install(c.out)
+    assert "CMAKE_INSTALL_PREFIX" in c.out
+
+    c.run("build .")
+    _assert_install(c.out)
+    assert "CMAKE_INSTALL_PREFIX" not in c.out