affected is broken due to incorrect gitignore handling

[cdaringe]

Current Behavior

affected -t build --files=packages/foo/src/index.ts yields no output

Expected Behavior

The above command should yield package foo

GitHub Repo

n/a

Steps to Reproduce

n/a

You can reproduce, but see below conversation. This behavior is traced.

Nx Report

19.7.2

Failure Logs

n/a

Package Manager Version

No response

Operating System

• macOS
• Linux
• Windows
• Other (Please specify)

Additional Information

Here's the scoop.

Suppose you have two types of packages:

• package type foo, e.g. a generic node lib
• package type bar

The {workspaceRoot}/.gitignore has:

# {workspaceRoot}/.gitignore
src/**

...in it, because 99% of your packages are bars. Imagine that bar packages are all codegen'd, so you don't want to track src. It seemed easier to to put this in the root ignore vs every per-package gitignore.

Now, imagine that packages/foo undoes that root gitignore with:

# {workspaceRoot}/packages/foo/.gitignore
!src/**

Now, try doing affected --files=packages/foo/src/some/modue.ts. Bummer, affected says that foo is not affected!

TLDR: https://github.com/nrwl/nx/blob/b6140d459020847818b738ddc17e52c069657893/packages/nx/src/project-graph/file-utils.ts#L67C12-L67C27 does not consider package gitignores, thus incorrectly computes affected.

Discussion:

• affected should pick up on project/package level gitignores, or
• error on their presence, as they lead to surprising behavior