ENH: Create $CACHE{VAR} syntax

This syntax allows reading of cache entries even when variables of the
same name have been defined in the local scope.  See issue #7715.

2 files changed, 30 insertions, 1 deletions

diff --git a/Source/cmCommandArgumentParserHelper.cxx b/Source/cmCommandArgumentParserHelper.cxx
index 2aa6c0c..c67f884 100644
--- a/Source/cmCommandArgumentParserHelper.cxx
+++ b/Source/cmCommandArgumentParserHelper.cxx
@@ -87,9 +87,24 @@ char* cmCommandArgumentParserHelper::ExpandSpecialVariable(const char* key,
       }
     return this->EmptyVariable;
     }
+  if ( strcmp(key, "CACHE") == 0 )
+    {
+    if(const char* c = this->Makefile->GetCacheManager()->GetCacheValue(var))
+      {
+      if(this->EscapeQuotes)
+        {
+        return this->AddString(cmSystemTools::EscapeQuotes(c).c_str());
+        }
+      else
+        {
+        return this->AddString(c);
+        }
+      }
+    return this->EmptyVariable;
+    }
   cmOStringStream e;
   e << "Syntax $" << key << "{} is not supported.  "
-    << "Only ${} and ENV{} are allowed.";
+    << "Only ${}, $ENV{}, and $CACHE{} are allowed.";
   this->SetError(e.str());
   return 0;
 }
diff --git a/Tests/Unset/CMakeLists.txt b/Tests/Unset/CMakeLists.txt
index 05a7e03..bacb6d2 100644
--- a/Tests/Unset/CMakeLists.txt
+++ b/Tests/Unset/CMakeLists.txt
@@ -32,6 +32,20 @@ if(NOT DEFINED BAR)
   message(FATAL_ERROR "BAR not defined")
 endif(NOT DEFINED BAR)
 
+# Test interaction of cache entries with variables.
+set(BAR "test-var")
+if(NOT "$CACHE{BAR}" STREQUAL "test")
+  message(FATAL_ERROR "\$CACHE{BAR} changed by variable BAR")
+endif(NOT "$CACHE{BAR}" STREQUAL "test")
+if(NOT "${BAR}" STREQUAL "test-var")
+  message(FATAL_ERROR "\${BAR} not separate from \$CACHE{BAR}")
+endif(NOT "${BAR}" STREQUAL "test-var")
+unset(BAR)
+if(NOT "${BAR}" STREQUAL "test")
+  message(FATAL_ERROR "\${BAR} does not fall through to \$CACHE{BAR}")
+endif(NOT "${BAR}" STREQUAL "test")
+
+# Test unsetting of CACHE entry.
 unset(BAR CACHE)
 if(DEFINED BAR)
   message(FATAL_ERROR "BAR still defined")