sqlite_empty_fail.go

package main

import (
	"database/sql"
	"fmt"

	_ "code.google.com/p/go-sqlite/go1/sqlite3"
)

var a string
var b = ""

func main() {
	db, _ := sql.Open("sqlite3", "test.db")
	db.Exec("CREATE TABLE a (a)")

	c := ""
	var d string
	var e = ""
	f := make([]string, 1)
	g := []string{""}
	h := make(map[int]string)
	i := map[int]string{0: ""}
	j := struct{ a string }{}
	k := struct{ a string }{""}

	s, _ := db.Prepare("INSERT INTO a (a) VALUES (?)")
	s.Exec("")
	s.Exec(a)
	s.Exec(b)
	s.Exec(c)
	s.Exec(d)
	s.Exec(e)
	s.Exec(f[0])
	s.Exec(g[0])
	s.Exec(h[0])
	s.Exec(i[0])
	s.Exec(j.a)
	s.Exec(k.a)

	for z := 1; z <= 12; z++ {
		var out *string
		err := db.QueryRow("SELECT a FROM a WHERE rowid = ? AND a IS NOT NULL", z).Scan(&out)
		if err == sql.ErrNoRows {
			fmt.Println(string(" abcdefghijk"[z-1]), "is NULL")
		}
	}

	var count int
	db.QueryRow("SELECT COUNT(*) FROM a").Scan(&count)
	fmt.Println("count:", count)
}

// go version go1.1 darwin/amd64 OUTPUT:
// a is NULL
// b is NULL
// d is NULL
// f is NULL
// h is NULL
// j is NULL
// count: 12

Probably has to do with this:

// cStr returns a pointer to the first byte in s. s must end with '\x00' to be
// used as a regular C string.
func cStr(s string) *C.char {
        h := (*reflect.StringHeader)(unsafe.Pointer(&s))
        return (*C.char)(unsafe.Pointer(h.Data))
}

https://code.google.com/p/go-sqlite/source/browse/go1/sqlite3/util.go#267

Quick fix:

+var emptyStr = C.CString("")
+
 // cStr returns a pointer to the first byte in s. s must end with '\x00' to be
 // used as a regular C string.
 func cStr(s string) *C.char {
+       if len(s) == 0 {
+               return emptyStr
+       }
        h := (*reflect.StringHeader)(unsafe.Pointer(&s))
        return (*C.char)(unsafe.Pointer(h.Data))
 }

Fixed: https://code.google.com/p/go-sqlite/source/detail?r=017b55634475b5c3cdec5c80aaca1e2ddc6e4dd4