奇怪的行为GoLang将字符串存储到变量中的长度限制为64个字节

Question

I have been trying to store a large string into a string variable in GoLang , but for some unknown reason GoLang is limiting the string to 64 Bytes in length

The main purpose of this string concatenation is to generate a couchbase's N1QL query at runtime based on user input

userInput := []string{"apple", "boy", "cat", "dog"} 
var buffer string 
buffer = "SELECT * FROM DB WHERE DB.ITEM_NAME="+userInput[0]+
         "OR DB.ITEM_NAME="+userInput[1]

In such a case if I debug on variable buffer, for example I can see it contains only until "SELECT * FROM DB WHERE DB.ITEM_NAME="+userInput[0]+OR" depending upon user input size it varies and it caps the string to 64th character

Answer 1

The behaviour is as expected. The behaviour is not strange.

Your code creates obviously wrong Couchbase N1QL:

package main

import (
    "fmt"
)

func main() {
    userInput := []string{"apple", "boy", "cat", "dog"}
    var buffer string
    buffer = "SELECT * FROM DB WHERE DB.ITEM_NAME=" + userInput[0] +
        "OR DB.ITEM_NAME=" + userInput[1]
    fmt.Println(buffer)
}

Output:

SELECT * FROM DB WHERE DB.ITEM_NAME=appleOR DB.ITEM_NAME=boy

Here is a plausible solution:

package main

import (
    "fmt"
)

func main() {
    userInput := []string{"apple", "boy", "cat", "dog"}
    query := fmt.Sprintf(
        `SELECT * FROM DB WHERE DB.ITEM_NAME=%q OR DB.ITEM_NAME=%q;`,
        userInput[0], userInput[1],
    )
    fmt.Println(query)
}

Output:

SELECT * FROM DB WHERE DB.ITEM_NAME="apple" OR DB.ITEM_NAME="boy";

Note: Beware of SQL injection.

References:

The Go Programming Language Specification

Couchbase: Query Language Tutorial

Couchbase: Querying with N1QL