From 0bb1cd5e2ea4021a2e5080265f0a11e3924a74d0 Mon Sep 17 00:00:00 2001
From: Nuno Cruces <ncruces@users.noreply.github.com>
Date: Wed, 20 Dec 2023 16:10:32 +0000
Subject: [PATCH] Rework error messages, see #45.

---
 ext/array/array.go            | 14 +++++++-------
 internal/util/reflect.go      | 10 ++++++++++
 internal/util/reflect_test.go | 21 +++++++++++++++++++++
 3 files changed, 38 insertions(+), 7 deletions(-)
 create mode 100644 internal/util/reflect.go
 create mode 100644 internal/util/reflect_test.go

diff --git a/ext/array/array.go b/ext/array/array.go
index f10c508..921aa1b 100644
--- a/ext/array/array.go
+++ b/ext/array/array.go
@@ -8,6 +8,7 @@ import (
 	"reflect"
 
 	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
 )
 
 // Register registers the array single-argument, table-valued SQL function.
@@ -102,7 +103,7 @@ func (c *cursor) Column(ctx *sqlite3.Context, n int) error {
 		ctx.ResultBlob(v.Bytes())
 
 	default:
-		return fmt.Errorf("array: unsupported element:%.0w %v", sqlite3.MISMATCH, v.Type())
+		return fmt.Errorf("array: unsupported element:%.0w %v", sqlite3.MISMATCH, util.ReflectType(v))
 	}
 	return nil
 }
@@ -120,16 +121,15 @@ func (c *cursor) Filter(idxNum int, idxStr string, arg ...sqlite3.Value) error {
 }
 
 func indexable(v reflect.Value) (reflect.Value, error) {
-	if v.Kind() == reflect.Slice {
+	switch v.Kind() {
+	case reflect.Slice:
 		return v, nil
-	}
-	if v.Kind() == reflect.Array {
+	case reflect.Array:
 		return v, nil
-	}
-	if v.Kind() == reflect.Pointer {
+	case reflect.Pointer:
 		if v := v.Elem(); v.Kind() == reflect.Array {
 			return v, nil
 		}
 	}
-	return v, fmt.Errorf("array: unsupported argument:%.0w %v", sqlite3.MISMATCH, v)
+	return v, fmt.Errorf("array: unsupported argument:%.0w %v", sqlite3.MISMATCH, util.ReflectType(v))
 }
diff --git a/internal/util/reflect.go b/internal/util/reflect.go
new file mode 100644
index 0000000..3104a7c
--- /dev/null
+++ b/internal/util/reflect.go
@@ -0,0 +1,10 @@
+package util
+
+import "reflect"
+
+func ReflectType(v reflect.Value) reflect.Type {
+	if v.Kind() != reflect.Invalid {
+		return v.Type()
+	}
+	return nil
+}
diff --git a/internal/util/reflect_test.go b/internal/util/reflect_test.go
new file mode 100644
index 0000000..72a19a8
--- /dev/null
+++ b/internal/util/reflect_test.go
@@ -0,0 +1,21 @@
+package util
+
+import (
+	"fmt"
+	"math"
+	"reflect"
+	"testing"
+)
+
+func TestReflectType(t *testing.T) {
+	tests := []any{nil, 1, math.Pi, "abc"}
+	for _, tt := range tests {
+		t.Run(fmt.Sprint(tt), func(t *testing.T) {
+			want := fmt.Sprintf("%T", tt)
+			got := fmt.Sprintf("%v", ReflectType(reflect.ValueOf(tt)))
+			if got != want {
+				t.Errorf("ReflectType() = %v, want %v", got, want)
+			}
+		})
+	}
+}