From 28ea2cd1905808c0d7d9db0bc573ee4861ef91c6 Mon Sep 17 00:00:00 2001
From: Jack Christensen <jack@jackchristensen.com>
Date: Sat, 5 Feb 2022 13:05:23 -0600
Subject: [PATCH] Better error messages

---
 pgtype/array_codec.go |  2 +-
 pgtype/pgtype.go      | 12 +++++++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/pgtype/array_codec.go b/pgtype/array_codec.go
index 901ea5f7..5a02c435 100644
--- a/pgtype/array_codec.go
+++ b/pgtype/array_codec.go
@@ -250,7 +250,7 @@ func (c *ArrayCodec) decodeBinary(ci *ConnInfo, arrayOID uint32, src []byte, arr
 		}
 		err = elementScanPlan.Scan(elemSrc, elem)
 		if err != nil {
-			return err
+			return fmt.Errorf("failed to scan array element %d: %w", i, err)
 		}
 	}
 
diff --git a/pgtype/pgtype.go b/pgtype/pgtype.go
index 571b5bfc..45b9a092 100644
--- a/pgtype/pgtype.go
+++ b/pgtype/pgtype.go
@@ -489,7 +489,17 @@ type scanPlanFail struct {
 }
 
 func (plan *scanPlanFail) Scan(src []byte, dst interface{}) error {
-	return fmt.Errorf("cannot scan OID %v in format %v into %T", plan.oid, plan.formatCode, dst)
+	var format string
+	switch plan.formatCode {
+	case TextFormatCode:
+		format = "text"
+	case BinaryFormatCode:
+		format = "binary"
+	default:
+		format = fmt.Sprintf("unknown %d", plan.formatCode)
+	}
+
+	return fmt.Errorf("cannot scan OID %v in %v format into %T", plan.oid, format, dst)
 }
 
 // TryWrapScanPlanFunc is a function that tries to create a wrapper plan for target. If successful it returns a plan