Merge topic 'deprecate-policy-old'

6845e2559d Add deprecation warnings for policies CMP0065 and below

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !2793

Help/release/dev/deprecate-policy-old.rst

@@ -0,0 +1,8 @@
+deprecate-policy-old
+--------------------
+
+* An explicit deprecation diagnostic was added for policies ``CMP0064``
+  and ``CMP0065`` (``CMP0063`` and below were already deprecated).
+  The :manual:`cmake-policies(7)` manual explains that the OLD behaviors
+  of all policies are deprecated and that projects should port to the
+  NEW behaviors.

Source/cmMakefile.cxx

@@ -4232,7 +4232,11 @@ bool cmMakefile::SetPolicy(cmPolicies::PolicyID id,
 
   // Deprecate old policies, especially those that require a lot
   // of code to maintain the old behavior.
-  if (status == cmPolicies::OLD && id <= cmPolicies::CMP0063) {
+  if (status == cmPolicies::OLD && id <= cmPolicies::CMP0065 &&
+      !(this->GetCMakeInstance()->GetIsInTryCompile() &&
+        (
+          // Policies set by cmCoreTryCompile::TryCompileCode.
+          id == cmPolicies::CMP0065))) {
     this->IssueMessage(cmake::DEPRECATION_WARNING,
                        cmPolicies::GetPolicyDeprecatedWarning(id));
   }

Tests/RunCMake/CMP0064/CMP0064-OLD-stderr.txt

@@ -0,0 +1,10 @@
+^CMake Deprecation Warning at CMP0064-OLD.cmake:1 \(cmake_policy\):
+  The OLD behavior for policy CMP0064 will be removed from a future version
+  of CMake.
+
+  The cmake-policies\(7\) manual explains that the OLD behaviors of all
+  policies are deprecated and that a policy should be set to OLD only under
+  specific short-term circumstances.  Projects should be ported to the NEW
+  behavior and not rely on setting a policy to OLD.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)$