njs: If two or more "location" block defines the same "js_var" directive name, the value will be overwritten

Abstract:

If two or more “location” block defines the same “js_var” directive name, the value in the previous “location” block will be overwritten by the next “location” block. This behaviour is not the same as the “set” directive, it should be consider as a bug.

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Detail:

js_content directive can pass “module.function” which only accept one paramter (r: NginxHTTPRequest), but sometimes developer want to pass more paramters by location block with same “module.function”. js_var or set may be used as this idea.

The problem is, when use the same name in js_var, the last one will overwrite the previous one. that means value isolation by location block fail.

This behavior does not exist in the “set” directive, so it should be consider as a bug.

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Environment & Version:

CentOS 7 nginx.x86_64 1:1.25.2-1.el7.ngx nginx-module-njs.x86_64 1:1.25.2+0.8.0-1.el7.ngx

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Steps to reproduce:

nginx.conf:

server {
    listen       8765;
    server_name  localhost;
    

    js_import test from test.js;

    location /test {
        js_var $js_var_test "js_var_test from /test";
        set $set_test "set_test from /test";
        js_content test.test;
    }

    location /test2 {
        js_var $js_var_test "js_var_test from /test2";
        set $set_test "set_test from /test2";
        js_content test.test;
    }

}

test.js:

function test(r){
    r.return(200, JSON.stringify({
        "js_var_test": r.variables.js_var_test,
        "set_test": r.variables.set_test
    }));
}


export default {test};

curl /test:

curl -v "http://localhost:8765/test" curl /test2:

curl -v "http://localhost:8765/test2"

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What is expected?

Started from “from” string, the value from js_var_test should be the same as set_test.

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What is actually happening?

curl /test:

{"js_var_test":"js_var_test from /test2","set_test":"set_test from /test"} (js_var_test is overwritten)

curl /test2:

{"js_var_test":"js_var_test from /test2","set_test":"set_test from /test2"}