return(): Propagate variables to result scope

Fixes: #23871

1 files changed, 42 insertions, 2 deletions

diff --git a/Source/cmReturnCommand.cxx b/Source/cmReturnCommand.cxx
index 5905669..765b772 100644
--- a/Source/cmReturnCommand.cxx
+++ b/Source/cmReturnCommand.cxx
@@ -2,12 +2,52 @@
    file Copyright.txt or https://cmake.org/licensing for details.  */
 #include "cmReturnCommand.h"
 
+#include <cm/string_view>
+#include <cmext/string_view>
+
 #include "cmExecutionStatus.h"
+#include "cmMakefile.h"
+#include "cmMessageType.h"
+#include "cmPolicies.h"
+#include "cmStringAlgorithms.h"
+#include "cmSystemTools.h"
 
 // cmReturnCommand
-bool cmReturnCommand(std::vector<std::string> const&,
+bool cmReturnCommand(std::vector<std::string> const& args,
                      cmExecutionStatus& status)
 {
-  status.SetReturnInvoked();
+  if (!args.empty()) {
+    switch (status.GetMakefile().GetPolicyStatus(cmPolicies::CMP0140)) {
+      case cmPolicies::WARN:
+        status.GetMakefile().IssueMessage(
+          MessageType::AUTHOR_WARNING,
+          cmStrCat(
+            cmPolicies::GetPolicyWarning(cmPolicies::CMP0140), '\n',
+            "return() checks its arguments when the policy is set to NEW. "
+            "Since the policy is not set the OLD behavior will be used so "
+            "the arguments will be ignored."));
+        CM_FALLTHROUGH;
+      case cmPolicies::OLD:
+        return true;
+      case cmPolicies::REQUIRED_IF_USED:
+      case cmPolicies::REQUIRED_ALWAYS:
+        status.GetMakefile().IssueMessage(
+          MessageType::FATAL_ERROR,
+          cmStrCat('\n', cmPolicies::GetPolicyWarning(cmPolicies::CMP0140)));
+        cmSystemTools::SetFatalErrorOccurred();
+        return false;
+      default:
+        break;
+    }
+    if (args[0] != "PROPAGATE"_s) {
+      status.SetError(
+        cmStrCat("called with unsupported argument \"", args[0], '"'));
+      cmSystemTools::SetFatalErrorOccurred();
+      return false;
+    }
+    status.SetReturnInvoked({ args.begin() + 1, args.end() });
+  } else {
+    status.SetReturnInvoked();
+  }
   return true;
 }