Add generator expression $<GLOBAL_PROPERTY>

Fixes: #28121

Help/manual/cmake-generator-expressions.7.rst

@@ -1449,6 +1449,19 @@ Configuration Expressions
   in ``...`` are evaluated using the custom command's "command config".
   With other generators, the content of ``...`` is evaluated normally.
 
+Global Expressions
+------------------
+
+Global Properties
+^^^^^^^^^^^^^^^^^
+
+.. genex:: $<GLOBAL_PROPERTY:prop>
+
+  .. versionadded:: 4.5
+
+  Value of the global property ``prop``, or empty if
+  the property is not set.
+
 Rule-Dependent Expressions
 --------------------------
 

Help/release/dev/GenEx-GLOBAL_PROPERTY.rst

@@ -0,0 +1,5 @@
+GenEx-GLOBAL_PROPERTY
+---------------------
+
+* CMake gains the :genex:`GLOBAL_PROPERTY` generator expression to query
+  global properties.

Source/cmGeneratorExpressionNode.cxx

@@ -4080,6 +4080,31 @@ static const struct DeviceLinkNode : public cmGeneratorExpressionNode
   }
 } deviceLinkNode;
 
+static const struct GlobalPropertyNode : public cmGeneratorExpressionNode
+{
+  GlobalPropertyNode() {} // NOLINT(modernize-use-equals-default)
+
+  // This node handles errors on parameter count itself.
+  int NumExpectedParameters() const override { return 1; }
+
+  std::string Evaluate(
+    std::vector<std::string> const& parameters, cm::GenEx::Evaluation* eval,
+    GeneratorExpressionContent const* content,
+    cmGeneratorExpressionDAGChecker* /*dagCheckerParent*/) const override
+  {
+    auto const& propertyName = parameters[0];
+
+    if (propertyName.empty()) {
+      reportError(eval, content->GetOriginalExpression(),
+                  "$<GLOBAL_PROPERTY:property> expression requires a "
+                  "non-empty property name.");
+      return std::string{};
+    }
+    cmake* cm = eval->Context.LG->GetCMakeInstance();
+    return cm->GetState()->GetGlobalProperty(propertyName);
+  }
+} globalPropertyNode;
+
 namespace {
 bool GetFileSet(std::vector<std::string> const& parameters,
                 cm::GenEx::Evaluation* eval,
@@ -6538,6 +6563,7 @@ cmGeneratorExpressionNode const* cmGeneratorExpressionNode::GetNode(
     { "COMMA", &commaNode },
     { "SEMICOLON", &semicolonNode },
     { "QUOTE", &quoteNode },
+    { "GLOBAL_PROPERTY", &globalPropertyNode },
     { "RULE_PROPERTY", &rulePropertyNode },
     { "SOURCE_EXISTS", &sourceExistsNode },
     { "SOURCE_PROPERTY", &sourcePropertyNode },

Tests/RunCMake/CMakeLists.txt

@@ -573,6 +573,7 @@ add_RunCMake_test(GenEx-LINK_GROUP)
 add_RunCMake_test(GenEx-TARGET_FILE -DLINKER_SUPPORTS_PDB=${LINKER_SUPPORTS_PDB})
 add_RunCMake_test(GenEx-TARGET_IMPORT_FILE)
 add_RunCMake_test(GenEx-GENEX_EVAL)
+add_RunCMake_test(GenEx-GLOBAL_PROPERTY)
 add_RunCMake_test(GenEx-RULE_PROPERTY)
 add_RunCMake_test(GenEx-SOURCE_EXISTS)
 add_RunCMake_test(GenEx-SOURCE_PROPERTY)

Tests/RunCMake/GenEx-GLOBAL_PROPERTY/CMakeLists.txt

@@ -0,0 +1,5 @@
+cmake_minimum_required(VERSION 4.0...4.4)
+
+project(${RunCMake_TEST} NONE)
+
+include(${RunCMake_TEST}.cmake)

Tests/RunCMake/GenEx-GLOBAL_PROPERTY/GLOBAL_PROPERTY-check.cmake

@@ -0,0 +1,5 @@
+file(READ "${RunCMake_TEST_BINARY_DIR}/GLOBAL_PROPERTY-generated.txt" content)
+
+if(NOT content MATCHES "ENABLED_LANGUAGES=C;CXX" OR NOT content MATCHES "DEBUG_CONFIGURATIONS=Debug;Foo")
+  set(RunCMake_TEST_FAILED "actual content:\n [[${content}]]\nbut expected:\n [[ENABLED_LANGUAGES=C;CXX\nDEBUG_CONFIGURATIONS=Debug;Foo]]")
+endif()

Tests/RunCMake/GenEx-GLOBAL_PROPERTY/GLOBAL_PROPERTY.cmake

@@ -0,0 +1,7 @@
+
+enable_language(C)
+enable_language(CXX)
+
+set_property(GLOBAL PROPERTY DEBUG_CONFIGURATIONS Debug Foo)
+
+file(GENERATE OUTPUT GLOBAL_PROPERTY-generated.txt CONTENT "ENABLED_LANGUAGES=$<GLOBAL_PROPERTY:ENABLED_LANGUAGES>\nDEBUG_CONFIGURATIONS=$<GLOBAL_PROPERTY:DEBUG_CONFIGURATIONS>\n")

Tests/RunCMake/GenEx-GLOBAL_PROPERTY/RunCMakeTest.cmake

@@ -0,0 +1,6 @@
+
+include(RunCMake)
+
+run_cmake(no-arguments)
+run_cmake(no-property)
+run_cmake(GLOBAL_PROPERTY)

Tests/RunCMake/GenEx-GLOBAL_PROPERTY/no-arguments-result.txt

@@ -0,0 +1 @@
+1

Tests/RunCMake/GenEx-GLOBAL_PROPERTY/no-arguments-stderr.txt

@@ -0,0 +1,8 @@
+CMake Error at no-arguments\.cmake:[0-9]+ \(file\):
+  Error evaluating generator expression:
+
+    \$<GLOBAL_PROPERTY>
+
+  \$<GLOBAL_PROPERTY> expression requires exactly one parameter\.
+Call Stack \(most recent call first\):
+  CMakeLists\.txt:[0-9]+ \(include\)

Tests/RunCMake/GenEx-GLOBAL_PROPERTY/no-arguments.cmake

@@ -0,0 +1,2 @@
+
+file(GENERATE OUTPUT result.txt CONTENT "$<GLOBAL_PROPERTY>")

Tests/RunCMake/GenEx-GLOBAL_PROPERTY/no-property-result.txt

@@ -0,0 +1 @@
+1

Tests/RunCMake/GenEx-GLOBAL_PROPERTY/no-property-stderr.txt

@@ -0,0 +1,8 @@
+CMake Error at no-property\.cmake:[0-9]+ \(file\):
+  Error evaluating generator expression:
+
+    \$<GLOBAL_PROPERTY:>
+
+  \$<GLOBAL_PROPERTY:property> expression requires a non-empty property name\.
+Call Stack \(most recent call first\):
+  CMakeLists\.txt:[0-9]+ \(include\)

Tests/RunCMake/GenEx-GLOBAL_PROPERTY/no-property.cmake

@@ -0,0 +1,2 @@
+
+file(GENERATE OUTPUT result.txt CONTENT "$<GLOBAL_PROPERTY:>")