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authorEelco Dolstra <e.dolstra@tudelft.nl>2010-04-08T11·25+0000
committerEelco Dolstra <e.dolstra@tudelft.nl>2010-04-08T11·25+0000
commit7e048eddf55637b9e81d704f6b9f1fdeca98a5ea (patch)
treec2f39dec45c5e2c6b84f7cde29fbd03438038481 /src
parentaf2a372bb000d4d5aeec37e43ee0f6245c1bba54 (diff)
* Fix blackholing. If evaluation fails due to an assertion failure,
  then the blackhole has to be removed to ensure that repeated
  evaluation of the same value gives an assertion failure again rather
  than an "infinite recursion" error.

Diffstat (limited to 'src')
-rw-r--r--src/libexpr/eval.cc10
1 files changed, 8 insertions, 2 deletions
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 98b6b7bdd150..e72538e60874 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -681,8 +681,14 @@ bool EvalState::evalBool(Env & env, Expr e)
 void EvalState::forceValue(Value & v)
 {
     if (v.type == tThunk) {
-        //v.type = tBlackhole;
-        eval(*v.thunk.env, v.thunk.expr, v);
+        ValueType saved = v.type;
+        try {
+            v.type = tBlackhole;
+            eval(*v.thunk.env, v.thunk.expr, v);
+        } catch (Error & e) {
+            v.type = saved;
+            throw;
+        }
     }
     else if (v.type == tCopy) {
         forceValue(*v.val);