Add deprecation warnings for policies CMP0069 and below

The OLD behaviors of all policies are deprecated, but only by
documentation.  Add an explicit deprecation diagnostic for policies
introduced in CMake 3.9 and below to encourage projects to port away
from setting policies to OLD.

5 files changed, 41 insertions, 2 deletions

diff --git a/Help/release/dev/deprecate-policy-old.rst b/Help/release/dev/deprecate-policy-old.rst
new file mode 100644
index 0000000..401f4b2
--- /dev/null
+++ b/Help/release/dev/deprecate-policy-old.rst
@@ -0,0 +1,8 @@
+deprecate-policy-old
+--------------------
+
+* An explicit deprecation diagnostic was added for policy ``CMP0068``
+  and policy ``CMP0069`` (``CMP0067`` 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.
diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index f143ef7..bf488b1 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -4487,7 +4487,7 @@ 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::CMP0067 &&
+  if (status == cmPolicies::OLD && id <= cmPolicies::CMP0069 &&
       !(this->GetCMakeInstance()->GetIsInTryCompile() &&
         (
           // Policies set by cmCoreTryCompile::TryCompileCode.
diff --git a/Tests/RunCMake/CMP0068/CMP0068-OLD-stderr.txt b/Tests/RunCMake/CMP0068/CMP0068-OLD-stderr.txt
new file mode 100644
index 0000000..a736129
--- /dev/null
+++ b/Tests/RunCMake/CMP0068/CMP0068-OLD-stderr.txt
@@ -0,0 +1,10 @@
+^CMake Deprecation Warning at CMP0068-OLD.cmake:[0-9]+ \(cmake_policy\):
+  The OLD behavior for policy CMP0068 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:[0-9]+ \(include\)$
diff --git a/Tests/RunCMake/CMP0069/CMP0069-OLD-stderr.txt b/Tests/RunCMake/CMP0069/CMP0069-OLD-stderr.txt
new file mode 100644
index 0000000..f51a6f4
--- /dev/null
+++ b/Tests/RunCMake/CMP0069/CMP0069-OLD-stderr.txt
@@ -0,0 +1,10 @@
+^CMake Deprecation Warning at CMP0069-OLD.cmake:[0-9]+ \(cmake_policy\):
+  The OLD behavior for policy CMP0069 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:[0-9]+ \(include\)$
diff --git a/Tests/RunCMake/CheckIPOSupported/cmp0069-is-old-stderr.txt b/Tests/RunCMake/CheckIPOSupported/cmp0069-is-old-stderr.txt
index f183594..1baa63a 100644
--- a/Tests/RunCMake/CheckIPOSupported/cmp0069-is-old-stderr.txt
+++ b/Tests/RunCMake/CheckIPOSupported/cmp0069-is-old-stderr.txt
@@ -1,4 +1,15 @@
-^CMake Error at .*/Modules/CheckIPOSupported\.cmake:[0-9]+ \(message\):
+^CMake Deprecation Warning at cmp0069-is-old.cmake:[0-9]+ \(cmake_policy\):
+  The OLD behavior for policy CMP0069 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:[0-9]+ \(include\)
++
+CMake Error at .*/Modules/CheckIPOSupported\.cmake:[0-9]+ \(message\):
   Policy CMP0069 set to OLD
 Call Stack \(most recent call first\):
   cmp0069-is-old\.cmake:[0-9]+ \(check_ipo_supported\)