Add deprecated / obsolete variable support

By calling the custom KATI_deprecated_var / KATI_obsolete_var functions,
variables may be marked as deprecated or obsolete.

When accessed or assigned, deprecated variables will print a warning.

When accessed or assigned, obsolete variables will print an error and
stop.

Variables do not need to be set before calling the functions, and will
persist the deprecation warning through a reassignment. This way we can
easily mark variables that are sometimes passed via the environment as
deprecated.

Change-Id: Id04c974c446f471a18cc173f817760f4a02b9239

1 files changed, 9 insertions, 2 deletions

diff --git a/eval.cc b/eval.cc
index 7a08be7..ecfcd50 100644
--- a/eval.cc
+++ b/eval.cc
@@ -55,7 +55,9 @@ Var* Evaluator::EvalRHS(Symbol lhs, Value* rhs_v, StringPiece orig_rhs,
        is_override ? VarOrigin::OVERRIDE : VarOrigin::FILE));
 
   Var* rhs = NULL;
+  Var* prev = LookupVarInCurrentScope(lhs);
   bool needs_assign = true;
+
   switch (op) {
     case AssignOp::COLON_EQ: {
       SimpleVar* sv = new SimpleVar(origin);
@@ -67,7 +69,6 @@ Var* Evaluator::EvalRHS(Symbol lhs, Value* rhs_v, StringPiece orig_rhs,
       rhs = new RecursiveVar(rhs_v, origin, orig_rhs);
       break;
     case AssignOp::PLUS_EQ: {
-      Var* prev = LookupVarInCurrentScope(lhs);
       if (!prev->IsDefined()) {
         rhs = new RecursiveVar(rhs_v, origin, orig_rhs);
       } else if (prev->ReadOnly()) {
@@ -80,7 +81,6 @@ Var* Evaluator::EvalRHS(Symbol lhs, Value* rhs_v, StringPiece orig_rhs,
       break;
     }
     case AssignOp::QUESTION_EQ: {
-      Var* prev = LookupVarInCurrentScope(lhs);
       if (!prev->IsDefined()) {
         rhs = new RecursiveVar(rhs_v, origin, orig_rhs);
       } else {
@@ -91,6 +91,13 @@ Var* Evaluator::EvalRHS(Symbol lhs, Value* rhs_v, StringPiece orig_rhs,
     }
   }
 
+  prev->Used(this, lhs);
+  if (prev->Deprecated()) {
+    if (needs_assign) {
+      rhs->SetDeprecated(prev->DeprecatedMessage());
+    }
+  }
+
   LOG("Assign: %s=%s", lhs.c_str(), rhs->DebugString().c_str());
   if (needs_assign) {
     return rhs;