From d0478d1538d229302f33cc2a6d753ab3c7d73bf3 Mon Sep 17 00:00:00 2001
From: oskarth <ot@oskarthoren.com>
Date: Fri, 25 Feb 2022 18:25:03 +0800
Subject: [PATCH] When constraints are unsatisfied, show first one (#21)

Useful for debugging
---
 src/circom/builder.rs | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/circom/builder.rs b/src/circom/builder.rs
index b0650ef..3cd2ac9 100644
--- a/src/circom/builder.rs
+++ b/src/circom/builder.rs
@@ -83,7 +83,15 @@ impl<E: PairingEngine> CircomBuilder<E> {
             use ark_relations::r1cs::{ConstraintSynthesizer, ConstraintSystem};
             let cs = ConstraintSystem::<E::Fr>::new_ref();
             circom.clone().generate_constraints(cs.clone()).unwrap();
-            cs.is_satisfied().unwrap()
+            let is_satisfied = cs.is_satisfied().unwrap();
+            if !is_satisfied {
+                println!(
+                    "Unsatisfied constraint: {:?}",
+                    cs.which_is_unsatisfied().unwrap()
+                );
+            }
+
+            is_satisfied
         });
 
         Ok(circom)