feat: add support for absolute imports

[david-luna]

protobuf.js version: 7.2.6

The load method forces to use relative import for other `.proto` files where the spec doesn't explicitly say this.

Create a project with the following proto files

// file: org/common/common.proto
package org.common;
syntax = "proto3";

message CommonMessage {
    string common_field = 1; // becomes commonField
}

// file: org/test/test.proto
package org.test;
syntax = "proto3";

import "org/common/common.proto";

message TestMessage {
    string test_field = 1; // becomes testField
    repeated org.common.CommonMessage common_fields = 2;
}

and try to load test.proto in node

const {load} = require('protobufjs');

load(`${__dirname}/org/test/test.proto`, (err, root) => {
  if (err) {
    console.error(err);
  }

  console.log(root);
})

the load process tries to load common.proto resolving the import from the current location of test.proto file giving the following error

[Error: ENOENT: no such file or directory, open '/.../proto-load/org/test/org/common/common.proto'] {
  errno: -2,
  code: 'ENOENT',
  syscall: 'open',
  path: '/.../proto-load/org/test/org/common/common.proto'
}

not the import path being appended to the path of the current file being processed

Making the import relative import "../common/common.proto" makes the error go away but I'm not sure that this is the behavior documented in https://protobuf.dev/programming-guides/proto3/#importing. I've checked load & loadSync but I've could not find a config to set a root path for imports.

I guess what is expected is to have a way to define a root path from where to resolve imports. https://github.com/open-telemetry/opentelemetry-proto seems to assume this.

[david-luna]

With v7.2.5 the error was not reported so you could load all files separately.

const {load} = require('protobufjs');

load(
  [
    `${__dirname}/org/common/common.proto`,
    `${__dirname}/org/test/test.proto`
  ],
  (err, root) => {
    if (err) {
      console.error(err);
    }
    console.log(root);
})

As a result of #1960 now we get the error