From 8e88a000fef547950875c7cb8d197ba8fee25f04 Mon Sep 17 00:00:00 2001
From: Artyom Pervukhin <github@artyom.dev>
Date: Wed, 18 May 2022 23:48:36 +0300
Subject: [PATCH] Fix handling of nil []byte as NULL values

This fixes a regression introduced in 87412bbfa9b5b979ca4d4e8ba69c347819b9c4da,
which changed nil []byte values by storing them as zero-sized blobs, instead of
NULLs.

Closes #100
---
 all_test.go | 34 ++++++++++++++++++++++++++++++++++
 sqlite.go   |  6 ++++--
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/all_test.go b/all_test.go
index 154350d..8f5d704 100644
--- a/all_test.go
+++ b/all_test.go
@@ -149,6 +149,40 @@ func tempDB(t testing.TB) (string, *sql.DB) {
 	return dir, db
 }
 
+// https://gitlab.com/cznic/sqlite/issues/100
+func TestIssue100(t *testing.T) {
+	db, err := sql.Open("sqlite", ":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	if _, err := db.Exec(`CREATE TABLE t1(v TEXT)`); err != nil {
+		t.Fatal(err)
+	}
+	var val []byte
+	if _, err := db.Exec(`INSERT INTO t1(v) VALUES(?)`, val); err != nil {
+		t.Fatal(err)
+	}
+	var res sql.NullByte
+	if err = db.QueryRow(`SELECT v FROM t1 LIMIT 1`).Scan(&res); err != nil {
+		t.Fatal(err)
+	}
+	if res.Valid {
+		t.Fatalf("got non-NULL result: %+v", res)
+	}
+
+	if _, err := db.Exec(`CREATE TABLE t2(
+		v TEXT check(v is NULL OR(json_valid(v) AND json_type(v)='array'))
+	)`); err != nil {
+		t.Fatal(err)
+	}
+	for _, val := range [...][]byte{nil, []byte(`["a"]`)} {
+		if _, err := db.Exec(`INSERT INTO t2(v) VALUES(?)`, val); err != nil {
+			t.Fatalf("inserting value %v (%[1]q): %v", val, err)
+		}
+	}
+}
+
 // https://gitlab.com/cznic/sqlite/issues/98
 func TestIssue98(t *testing.T) {
 	dir, db := tempDB(t)
diff --git a/sqlite.go b/sqlite.go
index 70d4007..109a11f 100644
--- a/sqlite.go
+++ b/sqlite.go
@@ -1147,7 +1147,7 @@ func (c *conn) bindText(pstmt uintptr, idx1 int, value string) (uintptr, error)
 
 // int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
 func (c *conn) bindBlob(pstmt uintptr, idx1 int, value []byte) (uintptr, error) {
-	if len(value) == 0 {
+	if value != nil && len(value) == 0 {
 		if rc := sqlite3.Xsqlite3_bind_zeroblob(c.tls, pstmt, int32(idx1), 0); rc != sqlite3.SQLITE_OK {
 			return 0, c.errstr(rc)
 		}
@@ -1158,7 +1158,9 @@ func (c *conn) bindBlob(pstmt uintptr, idx1 int, value []byte) (uintptr, error)
 	if err != nil {
 		return 0, err
 	}
-	copy((*libc.RawMem)(unsafe.Pointer(p))[:len(value):len(value)], value)
+	if len(value) != 0 {
+		copy((*libc.RawMem)(unsafe.Pointer(p))[:len(value):len(value)], value)
+	}
 	if rc := sqlite3.Xsqlite3_bind_blob(c.tls, pstmt, int32(idx1), p, int32(len(value)), 0); rc != sqlite3.SQLITE_OK {
 		c.free(p)
 		return 0, c.errstr(rc)