EVM: fix encoding of zero

Author: Stebalien

actors/evm/src/interpreter/precompiles/evm.rs

@@ -141,15 +141,15 @@ pub(super) fn modexp<RT: Runtime>(
     Ok(output)
 }
 
-pub(super) fn curve_to_vec(curve: G1) -> Result<Vec<u8>, PrecompileError> {
+pub(super) fn curve_to_vec(curve: G1) -> Vec<u8> {
     AffineG1::from_jacobian(curve)
         .map(|product| {
             let mut output = vec![0; 64];
             product.x().to_big_endian(&mut output[0..32]).unwrap();
             product.y().to_big_endian(&mut output[32..64]).unwrap();
             output
         })
-        .ok_or(PrecompileError::EcErr(substrate_bn::CurveError::InvalidEncoding))
+        .unwrap_or_default()
 }
 
 /// add 2 points together on an elliptic curve
@@ -162,7 +162,7 @@ pub(super) fn ec_add<RT: Runtime>(
     let point1: G1 = input_params.read_value()?;
     let point2: G1 = input_params.read_value()?;
 
-    curve_to_vec(point1 + point2)
+    Ok(curve_to_vec(point1 + point2))
 }
 
 /// multiply a point on an elliptic curve by a scalar value
@@ -175,7 +175,7 @@ pub(super) fn ec_mul<RT: Runtime>(
     let point: G1 = input_params.read_value()?;
     let scalar: Fr = input_params.read_value()?;
 
-    curve_to_vec(point * scalar)
+    Ok(curve_to_vec(point * scalar))
 }
 
 /// pairs multple groups of twisted bn curves