Add policy CMP0068 separate install_name and RPATH settings on macOS

BUILD_WITH_INSTALL_RPATH, SKIP_BUILD_RPATH, CMAKE_SKIP_RPATH and
CMAKE_SKIP_INSTALL_RPATH no longer any effect on the install name
of a target on macOS.

Fixes: #16589

4 files changed, 55 insertions, 2 deletions

diff --git a/Source/cmGeneratorTarget.cxx b/Source/cmGeneratorTarget.cxx
index d32bcd8..8512b99 100644
--- a/Source/cmGeneratorTarget.cxx
+++ b/Source/cmGeneratorTarget.cxx
@@ -1402,14 +1402,30 @@ bool cmGeneratorTarget::MacOSXUseInstallNameDir() const
     return cmSystemTools::IsOn(build_with_install_name);
   }
 
+  cmPolicies::PolicyStatus cmp0068 = this->GetPolicyStatusCMP0068();
+  if (cmp0068 == cmPolicies::NEW) {
+    return false;
+  }
+
   bool use_install_name = this->GetPropertyAsBool("BUILD_WITH_INSTALL_RPATH");
 
+  if (use_install_name && cmp0068 == cmPolicies::WARN) {
+    this->LocalGenerator->GetGlobalGenerator()->AddCMP0068WarnTarget(
+      this->GetName());
+  }
+
   return use_install_name;
 }
 
 bool cmGeneratorTarget::CanGenerateInstallNameDir(
   InstallNameType name_type) const
 {
+  cmPolicies::PolicyStatus cmp0068 = this->GetPolicyStatusCMP0068();
+
+  if (cmp0068 == cmPolicies::NEW) {
+    return true;
+  }
+
   bool skip = this->Makefile->IsOn("CMAKE_SKIP_RPATH");
   if (name_type == INSTALL_NAME_FOR_INSTALL) {
     skip |= this->Makefile->IsOn("CMAKE_SKIP_INSTALL_RPATH");
@@ -1417,6 +1433,11 @@ bool cmGeneratorTarget::CanGenerateInstallNameDir(
     skip |= this->GetPropertyAsBool("SKIP_BUILD_RPATH");
   }
 
+  if (skip && cmp0068 == cmPolicies::WARN) {
+    this->LocalGenerator->GetGlobalGenerator()->AddCMP0068WarnTarget(
+      this->GetName());
+  }
+
   return !skip;
 }
 
diff --git a/Source/cmGlobalGenerator.cxx b/Source/cmGlobalGenerator.cxx
index f118250..b6b7d9e 100644
--- a/Source/cmGlobalGenerator.cxx
+++ b/Source/cmGlobalGenerator.cxx
@@ -1194,6 +1194,11 @@ void cmGlobalGenerator::AddCMP0042WarnTarget(const std::string& target)
   this->CMP0042WarnTargets.insert(target);
 }
 
+void cmGlobalGenerator::AddCMP0068WarnTarget(const std::string& target)
+{
+  this->CMP0068WarnTargets.insert(target);
+}
+
 bool cmGlobalGenerator::CheckALLOW_DUPLICATE_CUSTOM_TARGETS() const
 {
   // If the property is not enabled then okay.
@@ -1235,6 +1240,8 @@ bool cmGlobalGenerator::Compute()
 
   // clear targets to issue warning CMP0042 for
   this->CMP0042WarnTargets.clear();
+  // clear targets to issue warning CMP0068 for
+  this->CMP0068WarnTargets.clear();
 
   // Check whether this generator is allowed to run.
   if (!this->CheckALLOW_DUPLICATE_CUSTOM_TARGETS()) {
@@ -1366,6 +1373,24 @@ void cmGlobalGenerator::Generate()
     this->GetCMakeInstance()->IssueMessage(cmake::AUTHOR_WARNING, w.str());
   }
 
+  if (!this->CMP0068WarnTargets.empty()) {
+    std::ostringstream w;
+    /* clang-format off */
+    w <<
+      cmPolicies::GetPolicyWarning(cmPolicies::CMP0068) << "\n"
+      "For compatibility with older versions of CMake, the install_name "
+      "fields for the following targets are still affected by RPATH "
+      "settings:\n"
+      ;
+    /* clang-format on */
+    for (std::set<std::string>::iterator iter =
+           this->CMP0068WarnTargets.begin();
+         iter != this->CMP0068WarnTargets.end(); ++iter) {
+      w << " " << *iter << "\n";
+    }
+    this->GetCMakeInstance()->IssueMessage(cmake::AUTHOR_WARNING, w.str());
+  }
+
   this->CMakeInstance->UpdateProgress("Generating done", -1);
 }
 
diff --git a/Source/cmGlobalGenerator.h b/Source/cmGlobalGenerator.h
index 18e3730..b3cb41f 100644
--- a/Source/cmGlobalGenerator.h
+++ b/Source/cmGlobalGenerator.h
@@ -357,6 +357,7 @@ public:
   cmExportBuildFileGenerator* GetExportedTargetsFile(
     const std::string& filename) const;
   void AddCMP0042WarnTarget(const std::string& target);
+  void AddCMP0068WarnTarget(const std::string& target);
 
   virtual void ComputeTargetObjectDirectory(cmGeneratorTarget* gt) const;
 
@@ -562,6 +563,8 @@ private:
 
   // track targets to issue CMP0042 warning for.
   std::set<std::string> CMP0042WarnTargets;
+  // track targets to issue CMP0068 warning for.
+  std::set<std::string> CMP0068WarnTargets;
 
   mutable std::map<cmSourceFile*, std::set<cmGeneratorTarget const*> >
     FilenameTargetDepends;
diff --git a/Source/cmPolicies.h b/Source/cmPolicies.h
index 62e67c7..ecf06b3 100644
--- a/Source/cmPolicies.h
+++ b/Source/cmPolicies.h
@@ -200,7 +200,10 @@ class cmMakefile;
          7, 0, cmPolicies::WARN)                                              \
   SELECT(POLICY, CMP0067,                                                     \
          "Honor language standard in try_compile() source-file signature.",   \
-         3, 8, 0, cmPolicies::WARN)
+         3, 8, 0, cmPolicies::WARN)                                           \
+  SELECT(POLICY, CMP0068,                                                     \
+         "RPATH settings on macOS do not affect install_name.", 3, 9, 0,      \
+         cmPolicies::WARN)
 
 #define CM_SELECT_ID(F, A1, A2, A3, A4, A5, A6) F(A1)
 #define CM_FOR_EACH_POLICY_ID(POLICY)                                         \
@@ -221,7 +224,8 @@ class cmMakefile;
   F(CMP0052)                                                                  \
   F(CMP0060)                                                                  \
   F(CMP0063)                                                                  \
-  F(CMP0065)
+  F(CMP0065)                                                                  \
+  F(CMP0068)
 
 /** \class cmPolicies
  * \brief Handles changes in CMake behavior and policies