From 2199e0a8a1f0d492d6e5476523b663cd6a99e0f3 Mon Sep 17 00:00:00 2001
From: Sam Kleinman <garen@tychoish.com>
Date: Fri, 14 Jan 2022 16:18:50 -0500
Subject: [PATCH] light: convert validation panics to errors (#7597)

---
 light/client_benchmark_test.go |  3 ++-
 light/verifier.go              | 25 ++++++++++++++++---------
 2 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/light/client_benchmark_test.go b/light/client_benchmark_test.go
index 38b44d271..59eb79766 100644
--- a/light/client_benchmark_test.go
+++ b/light/client_benchmark_test.go
@@ -2,6 +2,7 @@ package light_test
 
 import (
 	"context"
+	"errors"
 	"testing"
 	"time"
 
@@ -57,7 +58,7 @@ func (impl *providerBenchmarkImpl) LightBlock(ctx context.Context, height int64)
 }
 
 func (impl *providerBenchmarkImpl) ReportEvidence(_ context.Context, _ types.Evidence) error {
-	panic("not implemented")
+	return errors.New("not implemented")
 }
 
 func BenchmarkSequence(b *testing.B) {
diff --git a/light/verifier.go b/light/verifier.go
index ee4bfb053..f6156c5de 100644
--- a/light/verifier.go
+++ b/light/verifier.go
@@ -38,9 +38,12 @@ func VerifyNonAdjacent(
 	trustingPeriod time.Duration,
 	now time.Time,
 	maxClockDrift time.Duration,
-	trustLevel tmmath.Fraction) error {
+	trustLevel tmmath.Fraction,
+) error {
 
-	checkRequiredHeaderFields(trustedHeader)
+	if err := checkRequiredHeaderFields(trustedHeader); err != nil {
+		return err
+	}
 
 	if untrustedHeader.Height == trustedHeader.Height+1 {
 		return errors.New("headers must be non adjacent in height")
@@ -106,12 +109,15 @@ func VerifyAdjacent(
 	untrustedVals *types.ValidatorSet, // height=X+1
 	trustingPeriod time.Duration,
 	now time.Time,
-	maxClockDrift time.Duration) error {
+	maxClockDrift time.Duration,
+) error {
 
-	checkRequiredHeaderFields(trustedHeader)
+	if err := checkRequiredHeaderFields(trustedHeader); err != nil {
+		return err
+	}
 
 	if len(trustedHeader.NextValidatorsHash) == 0 {
-		panic("next validators hash in trusted header is empty")
+		return errors.New("next validators hash in trusted header is empty")
 	}
 
 	if untrustedHeader.Height != trustedHeader.Height+1 {
@@ -268,17 +274,18 @@ func verifyNewHeaderAndVals(
 	return nil
 }
 
-func checkRequiredHeaderFields(h *types.SignedHeader) {
+func checkRequiredHeaderFields(h *types.SignedHeader) error {
 	if h.Height == 0 {
-		panic("height in trusted header must be set (non zero")
+		return errors.New("height in trusted header must be set (non zero")
 	}
 
 	zeroTime := time.Time{}
 	if h.Time == zeroTime {
-		panic("time in trusted header must be set")
+		return errors.New("time in trusted header must be set")
 	}
 
 	if h.ChainID == "" {
-		panic("chain ID in trusted header must be set")
+		return errors.New("chain ID in trusted header must be set")
 	}
+	return nil
 }