Add set_property option: DEPRECATION

Add a new property flag for a target which contains a message regarding
deprecation status.

Add a warning at "Generate" time if a linked target is marked as
deprecated.

Expand ExportImport test to ensure that new property is being set and
passed correctly.  Ensure that the message is shown during the
"Generate" step run of the ExportImport test.

4 files changed, 42 insertions, 0 deletions

diff --git a/Source/cmExportFileGenerator.cxx b/Source/cmExportFileGenerator.cxx
index aeef602..7a4b887 100644
--- a/Source/cmExportFileGenerator.cxx
+++ b/Source/cmExportFileGenerator.cxx
@@ -1062,6 +1062,12 @@ void cmExportFileGenerator::GenerateImportTargetCode(
   if (target->IsCFBundleOnApple()) {
     os << "set_property(TARGET " << targetName << " PROPERTY BUNDLE 1)\n";
   }
+
+  // generate DEPRECATION
+  if (target->IsDeprecated()) {
+    os << "set_property(TARGET " << targetName << " PROPERTY DEPRECATION "
+       << cmExportFileGeneratorEscape(target->GetDeprecation()) << ")\n";
+  }
   os << "\n";
 }
 
diff --git a/Source/cmGeneratorTarget.cxx b/Source/cmGeneratorTarget.cxx
index 19d5b4d..927364d 100644
--- a/Source/cmGeneratorTarget.cxx
+++ b/Source/cmGeneratorTarget.cxx
@@ -6354,6 +6354,21 @@ std::string cmGeneratorTarget::CheckCMP0004(std::string const& item) const
   return lib;
 }
 
+bool cmGeneratorTarget::IsDeprecated() const
+{
+  const char* deprecation = this->GetProperty("DEPRECATION");
+  return deprecation && *deprecation;
+}
+
+std::string cmGeneratorTarget::GetDeprecation() const
+{
+  // find DEPRECATION property
+  if (const char* deprecation = this->GetProperty("DEPRECATION")) {
+    return deprecation;
+  }
+  return std::string();
+}
+
 void cmGeneratorTarget::GetLanguages(std::set<std::string>& languages,
                                      const std::string& config) const
 {
@@ -6624,6 +6639,19 @@ cmLinkItem cmGeneratorTarget::ResolveLinkItem(
     return cmLinkItem(resolved.String, bt);
   }
 
+  // Check deprecation, issue message with `bt` backtrace.
+  if (resolved.Target->IsDeprecated()) {
+    std::ostringstream w;
+    /* clang-format off */
+    w <<
+      "The library that is being linked to, "  << resolved.Target->GetName() <<
+      ", is marked as being deprecated by the owner.  The message provided by "
+      "the developer is: \n" << resolved.Target->GetDeprecation() << "\n";
+    /* clang-format on */
+    this->LocalGenerator->GetCMakeInstance()->IssueMessage(
+      MessageType::AUTHOR_WARNING, w.str(), bt);
+  }
+
   // Skip targets that will not really be linked.  This is probably a
   // name conflict between an external library and an executable
   // within the project.
diff --git a/Source/cmGeneratorTarget.h b/Source/cmGeneratorTarget.h
index eabd3fa9..0a72cbe 100644
--- a/Source/cmGeneratorTarget.h
+++ b/Source/cmGeneratorTarget.h
@@ -250,6 +250,13 @@ public:
   std::string GetAppBundleDirectory(const std::string& config,
                                     BundleDirectoryLevel level) const;
 
+  /** Return whether this target is marked as deprecated by the
+      maintainer  */
+  bool IsDeprecated() const;
+
+  /** Returns the deprecation message provided by the maintainer */
+  std::string GetDeprecation() const;
+
   /** Return whether this target is an executable Bundle, a framework
       or CFBundle on Apple.  */
   bool IsBundleOnApple() const;
diff --git a/Source/cmTargetPropertyComputer.cxx b/Source/cmTargetPropertyComputer.cxx
index baab8da..f37995c 100644
--- a/Source/cmTargetPropertyComputer.cxx
+++ b/Source/cmTargetPropertyComputer.cxx
@@ -62,6 +62,7 @@ bool cmTargetPropertyComputer::WhiteListedInterfaceProperty(
     "COMPATIBLE_INTERFACE_NUMBER_MAX",
     "COMPATIBLE_INTERFACE_NUMBER_MIN",
     "COMPATIBLE_INTERFACE_STRING",
+    "DEPRECATION",
     "EXPORT_NAME",
     "EXPORT_PROPERTIES",
     "IMPORTED",