Fix for #413 (#415)

src/backends/plonky2/mainpod/mod.rs

@@ -1,9 +1,9 @@
 pub mod operation;
-use crate::middleware::PodType;
+use crate::middleware::{wildcard_values_from_op_st, PodType};
 pub mod statement;
 use std::{iter, sync::Arc};
 
-use itertools::Itertools;
+use itertools::{zip_eq, Itertools};
 use num_bigint::BigUint;
 pub use operation::*;
 use plonky2::{hash::poseidon::PoseidonHash, plonk::config::Hasher};
@@ -37,9 +37,9 @@ use crate::{
         serialize_proof, serialize_verifier_only,
     },
     middleware::{
-        self, resolve_wildcard_values, value_from_op, CustomPredicateBatch,
+        self, value_from_op, CustomPredicateBatch, Error as MiddlewareError, Hash, MainPodInputs,
-        Error as MiddlewareError, Hash, MainPodInputs, MainPodProver, NativeOperation,
+        MainPodProver, NativeOperation, OperationType, Params, Pod, RawValue, StatementArg,
-        OperationType, Params, Pod, RawValue, StatementArg, ToFields, VDSet,
+        ToFields, VDSet,
     },
     timed,
 };
@@ -97,13 +97,17 @@ pub(crate) fn extract_custom_predicate_verifications(
     params: &Params,
     aux_list: &mut [OperationAux],
     operations: &[middleware::Operation],
+    statements: &[middleware::Statement],
     custom_predicate_batches: &[Arc<CustomPredicateBatch>],
 ) -> Result<Vec<CustomPredicateVerification>> {
     let mut table = Vec::new();
-    for (i, op) in operations.iter().enumerate() {
+    for (i, (op, st)) in zip_eq(operations.iter(), statements.iter()).enumerate() {
         if let middleware::Operation::Custom(cpr, sts) = op {
+            if let middleware::Statement::Custom(st_cpr, st_args) = st {
+                assert_eq!(cpr, st_cpr);
                 let wildcard_values =
-                resolve_wildcard_values(params, cpr.predicate(), sts).expect("resolved wildcards");
+                    wildcard_values_from_op_st(params, cpr.predicate(), sts, st_args)
+                        .expect("resolved wildcards");
                 let sts = sts.iter().map(|s| Statement::from(s.clone())).collect();
                 let batch_index = custom_predicate_batches
                     .iter()
@@ -119,6 +123,9 @@ pub(crate) fn extract_custom_predicate_verifications(
                     args: wildcard_values,
                     op_args: sts,
                 });
+            } else {
+                panic!("Custom operation paired with non-custom statement");
+            }
         }
     }
 
@@ -499,6 +506,7 @@ impl MainPodProver for Prover {
             params,
             &mut aux_list,
             inputs.operations,
+            inputs.statements,
             &custom_predicate_batches,
         )?;
         let public_key_of_sks =
@@ -823,6 +831,7 @@ pub mod tests {
         frontend::{
             self, literal, CustomPredicateBatchBuilder, MainPodBuilder, StatementTmplBuilder as STB,
         },
+        lang::parse,
         middleware::{
             self, containers::Set, CustomPredicateRef, NativePredicate as NP, Signer as _,
             DEFAULT_VD_LIST, DEFAULT_VD_SET,
@@ -1154,4 +1163,40 @@ pub mod tests {
         builder.prove(&prover)?;
         Ok(())
     }
+
+    #[test]
+    fn test_undetermined_values() {
+        let params = Default::default();
+        let batch = parse(
+            r#"
+            two_equal(x,y,z) = OR(
+                Equal(x,y)
+                Equal(y,z)
+                Equal(x,z)
+            )
+            "#,
+            &params,
+            &[],
+        )
+        .unwrap()
+        .custom_batch;
+        let mut builder = MainPodBuilder::new(&params, &DEFAULT_VD_SET);
+        let cpr = CustomPredicateRef { batch, index: 0 };
+        let eq_st = builder.priv_op(frontend::Operation::eq(1, 1)).unwrap();
+        let op = frontend::Operation::custom(
+            cpr.clone(),
+            [
+                eq_st,
+                middleware::Statement::None,
+                middleware::Statement::None,
+            ],
+        );
+        let st = middleware::Statement::Custom(
+            cpr,
+            [1, 1, 2].into_iter().map(middleware::Value::from).collect(),
+        );
+        builder.insert(true, (st, op)).unwrap();
+        let prover = Prover {};
+        builder.prove(&prover).unwrap();
+    }
 }

src/middleware/operation.rs

@@ -1,5 +1,6 @@
 use std::{fmt, iter};
 
+use itertools::Itertools;
 use log::error;
 use plonky2::field::types::Field;
 use serde::{Deserialize, Serialize};
@@ -14,8 +15,8 @@ use crate::{
     },
     middleware::{
         hash_values, AnchoredKey, CustomPredicate, CustomPredicateRef, Error, Hash, Key,
-        NativePredicate, Params, Predicate, Result, Statement, StatementArg, StatementTmpl,
+        MiddlewareInnerError, NativePredicate, Params, Predicate, Result, Statement, StatementArg,
-        StatementTmplArg, ToFields, TypedValue, Value, ValueRef, Wildcard, F,
+        StatementTmpl, StatementTmplArg, ToFields, TypedValue, Value, ValueRef, Wildcard, F,
     },
 };
 
@@ -613,16 +614,11 @@ pub fn check_st_tmpl(
     }
 }
 
-pub fn resolve_wildcard_values(
+pub fn fill_wildcard_values(
-    params: &Params,
     pred: &CustomPredicate,
     args: &[Statement],
-) -> Result<Vec<Value>> {
+    wildcard_map: &mut [Option<Value>],
-    // Check that all wildcard have consistent values as assigned in the statements while storing a
+) -> Result<()> {
-    // map of their values.
-    // NOTE: We assume the statements have the same order as defined in the custom predicate.  For
-    // disjunctions we expect Statement::None for the unused statements.
-    let mut wildcard_map = vec![None; params.max_custom_predicate_wildcards];
     for (st_tmpl, st) in pred.statements.iter().zip(args) {
         let st_args = st.args();
         st_tmpl
@@ -630,10 +626,25 @@ pub fn resolve_wildcard_values(
             .iter()
             .zip(&st_args)
             .try_for_each(|(st_tmpl_arg, st_arg)| {
-                check_st_tmpl(st_tmpl_arg, st_arg, &mut wildcard_map)
+                check_st_tmpl(st_tmpl_arg, st_arg, wildcard_map)
             })?;
     }
+    Ok(())
+}
 
+pub fn wildcard_values_from_op_st(
+    params: &Params,
+    pred: &CustomPredicate,
+    op_args: &[Statement],
+    st_args: &[Value],
+) -> Result<Vec<Value>> {
+    let mut wildcard_map = st_args
+        .iter()
+        .map(|v| Some(v.clone()))
+        .chain(core::iter::repeat(None))
+        .take(params.max_custom_predicate_wildcards)
+        .collect_vec();
+    fill_wildcard_values(pred, op_args, &mut wildcard_map)?;
     // NOTE: We set unresolved wildcard slots with an empty value.  They can be unresolved because
     // they are beyond the number of used wildcards in this custom predicate, or they could be
     // private arguments that are unused in a particular disjunction.
@@ -717,21 +728,24 @@ pub(crate) fn check_custom_pred(
         ));
     }
 
-    let wildcard_map = resolve_wildcard_values(params, pred, args)?;
-
     // Check that the resolved wildcards match the statement arguments.
-    for (arg_index, (s_arg, wc_value)) in s_args.iter().zip(wildcard_map.iter()).enumerate() {
+    match wildcard_values_from_op_st(params, pred, args, s_args) {
-        if *wc_value != *s_arg {
+        Ok(_) => Ok(()),
-            return Err(Error::mismatched_wildcard_value_and_statement_arg(
+        Err(Error::Inner { inner, backtrace }) => match *inner {
-                wc_value.clone(),
+            MiddlewareInnerError::InvalidWildcardAssignment(wc, v, prev)
-                s_arg.clone(),
+                if wc.index <= s_args.len() =>
-                arg_index,
+            {
+                Err(Error::mismatched_wildcard_value_and_statement_arg(
+                    v,
+                    prev,
+                    wc.index,
                     pred.clone(),
-            ));
+                ))
             }
+            _ => Err(Error::Inner { inner, backtrace }),
+        },
+        _ => unreachable!(),
     }
-
-    Ok(())
 }
 
 impl ToFields for Operation {