prog: validate deserialized programs

The optimization change removed validation too aggressively.
We do need program validation during deserialization,
because we can get bad programs from corpus or hub.
Restore program validation after deserialization.

1 files changed, 7 insertions, 2 deletions

diff --git a/prog/encoding.go b/prog/encoding.go
index 274e94a2d..151ff1935 100644
--- a/prog/encoding.go
+++ b/prog/encoding.go
@@ -27,8 +27,10 @@ func (p *Prog) String() string {
 }
 
 func (p *Prog) Serialize() []byte {
-	if err := p.validate(); err != nil {
-		panic("serializing invalid program")
+	if debug {
+		if err := p.validate(); err != nil {
+			panic("serializing invalid program")
+		}
 	}
 	buf := new(bytes.Buffer)
 	vars := make(map[*Arg]int)
@@ -173,6 +175,9 @@ func Deserialize(data []byte) (prog *Prog, err error) {
 	if err := p.Err(); err != nil {
 		return nil, err
 	}
+	// This validation is done even in non-debug mode because deserialization
+	// procedure does not catch all bugs (e.g. mismatched types).
+	// And we can receive bad programs from corpus and hub.
 	if err := prog.validate(); err != nil {
 		return nil, err
 	}