Relative external modules resolve to the wrong place when CWD too short

[mattdrose]

• Rollup Version: 1.14.2
• Operating System (or Browser): macOS, and Linux
• Node Version: v10.15.2

How Do We Reproduce?

1. Import a module that jumps up a couple directories
2. Build as an external cjs module
3. Mock process.cwd() to have less depth than the directories you jumped back

There's a REPL here: https://repl.it/@mattdrose/CiRollupExample

Expected Behavior

import Foo from '../../foo';

becomes

const Foo = require('../../foo');

Actual Behavior

import Foo from '../../foo';

becomes

const Foo = require('../foo');

Why is this happening?

I was able to trace the issue to this line:

rollup/src/Chunk.ts

Line 624 in b1df517

let relPath = this.id ? normalize(relative(dirname(this.id), depId)) : depId;

This resolves to:

path.relative('.', '../../foo');

Since node's path.relative is relative to process.cwd(), if process.cwd() offers less directories than what you're trying to jump back, it will begin to omit ../'s.

Having a cwd close to / is common in CI environments.

[lukastaegert]

Thanks, fix at #2901

[mattdrose]

Thanks so much for a quick fix 🙌