I suggest retiring pkg-config already too. i.e. Let's delete it and add a formula rename for pkg-config -> pkgconf.

That's a bit complicated as audit doesn't like usage of old names / aliases.

Assuming audit is not changed, either need to:

• Do a giant syntax-only migration of all pkg-config usage to pkgconf.
• Make pkg-config into a transitional formula that just installs pkgconf and then do the migration at a more leisurely pace. At the end, can squash pkg-config formula to either be a rename/alias of pkgconf.

We can just add a temporary exception for pkg-config and do the migration gradually.

Am OK with this PR given pkgconf and pkg-config are already conflicting.

In terms of switching our uses to pkgconf, the requirements are:

• pkgconf cannot conflict with pkg-config
• brew install pkg-config must continue to work (I'd probably go as far as saying it should continue to do so without warnings, i.e. as an alias)

Merging via renames and merging via alias however works completely differently. One uses the migrator mechanism and one doesn't. So will need to carefully test it.

I expect anything we do here to be "special", which may indeed mean adjusting things in brew to allow depends_on "pkg-config" (potentially for a long time/forever as it would affect so many third-party formulae).

Merging via renames and merging via alias however works completely differently. One uses the migrator mechanism and one doesn't. So will need to carefully test it.

At least pkgconf is using a higher version number so can be seen as an upgrade.

❯ brew outdated pkg-config
pkgconf (0.29.2_3) < 2.3.0_1

Though that also means the old version may remain for users who avoid upgrades.

For alias option, probably need Homebrew/brew#18675 in stable tag before continuing.

I guess one possible issue is if we update shim as a user that still has old pkg-config may not end up with pkgconf path:

https://github.com/Homebrew/brew/blob/master/Library/Homebrew/shims/mac/super/pkg-config#L5

Though, perhaps we shouldn't be using the explicit path. It does cause pkg-config to be silently added as a dependency as long as it is locally installed.

Maybe using the PATH lookup helper would align closer to our other shims.

Alias support available in 4.4.4. I think brew should just see this as an upgrade and handle like other version bumps.

Only bug I see is brew may not clean up the old Cellar. EDIT: A brew cleanup does handle leftover installation so easy way for users to deal with.

LGTM. CC @Homebrew/core for additional feedback.

Let's delete it and add a formula rename for pkg-config -> pkgconf.

I don't think we should do this. It's not a formula rename, it's another formula that we're migrating to.

I feel vaguely uneasy but OK about the pkg-config alias but the above is definitely a step too far.

Alias support available in 4.4.4. I think brew should just see this as an upgrade and handle like other version bumps.

@cho-m can you make sure you've tested this locally? Want to ensure that this is robust before this is merged.

At least the basic usage is all fine from tap. Testing without revision on pkgconf to check bottle usage.

• brew upgrade will install pkgconf and link it, e.g.

  $ brew outdated
  pkgconf (0.29.2_3) < 2.3.0
  
  $ brew upgrade
  ==> Upgrading 1 outdated package:
  pkg-config 2.3.0
  ==> Downloading https://ghcr.io/v2/homebrew/core/pkgconf/manifests/2.3.0
  Already downloaded: /Users/cho-m/Library/Caches/Homebrew/downloads/2f1a3719bf003aa9443a2e2e6af8e6441aa287088a24771231f191a9bcf36884--pkgconf-2.3.0.bottle_manifest.json
  ==> Fetching pkgconf
  ==> Downloading https://ghcr.io/v2/homebrew/core/pkgconf/blobs/sha256:9b44fe313d296fa10617d6b58ea1eab78bf217b6f00478ad98b01e0375475472
  Already downloaded: /Users/cho-m/Library/Caches/Homebrew/downloads/eed8a0a3462be8896edfce1cf6d726e4ebfd489cafecfb485f1b1b669a5d89af--pkgconf--2.3.0.sequoia.bottle.tar.gz
  ==> Upgrading pkg-config
    -> 2.3.0
  ==> Pouring pkgconf--2.3.0.sequoia.bottle.tar.gz
  🍺  /usr/local/Cellar/pkgconf/2.3.0: 25 files, 327.9KB
  ==> Running `brew cleanup pkgconf`...
  Disable this behaviour by setting HOMEBREW_NO_INSTALL_CLEANUP.
  Hide these hints with HOMEBREW_NO_ENV_HINTS (see `man brew`).
  Removing: /usr/local/Cellar/pkg-config/0.29.2_3... (12 files, 631.4KB)
  
  $ brew info pkg-config
  ==> pkgconf: stable 2.3.0 (bottled), HEAD
  Package compiler and linker metadata toolkit
  https://github.com/pkgconf/pkgconf
  Installed
  /usr/local/Cellar/pkgconf/2.3.0 (25 files, 327.9KB) *
    Poured from bottle on 2024-11-08 at 13:13:07
  From: https://github.com/Homebrew/homebrew-core/blob/HEAD/Formula/p/pkgconf.rb
  License: ISC
  ==> Options
  --HEAD
      Install HEAD version
  
  $ jq '.source' /usr/local/opt/pkg-config/INSTALL_RECEIPT.json
  {
    "spec": "stable",
    "versions": {
      "stable": "2.3.0",
      "head": null,
      "version_scheme": 0
    },
    "path": "/usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/Aliases/pkg-config",
    "tap_git_head": "afeea04d898316ef1ea37d87b80de9c9829550d7",
    "tap": "homebrew/core"
  }

• brew install <formula-with-pkg-config-dep> will automatically upgrade/install pkgconf and record it in receipt:

  $ brew install pkg-config
  ==> Downloading https://ghcr.io/v2/homebrew/core/pkg-config/manifests/0.29.2_3
  Already downloaded: /Users/cho-m/Library/Caches/Homebrew/downloads/ac691fc7ab8ecffba32a837e7197101d271474a3a84cfddcc30c9fd6763ab3c6--pkg-config-0.29.2_3.bottle_manifest.json
  ==> Fetching pkg-config
  ==> Downloading https://ghcr.io/v2/homebrew/core/pkg-config/blobs/sha256:55f4268c3d6f320932ce736e8ad862a98b27048a30481f85c0679d8c655fb0f6
  Already downloaded: /Users/cho-m/Library/Caches/Homebrew/downloads/25f2808beac7c455c7101ea7fb7f9ae61f5019163147d7e822e30a76ceb11263--pkg-config--0.29.2_3.sequoia.bottle.tar.gz
  ==> Pouring pkg-config--0.29.2_3.sequoia.bottle.tar.gz
  🍺  /usr/local/Cellar/pkg-config/0.29.2_3: 12 files, 631.5KB
  ==> Running `brew cleanup pkg-config`...
  Disable this behaviour by setting HOMEBREW_NO_INSTALL_CLEANUP.
  Hide these hints with HOMEBREW_NO_ENV_HINTS (see `man brew`).
  
  $ # update branch and revision
  
  $ brew install libpthread-stubs
  ==> Downloading https://ghcr.io/v2/homebrew/core/libpthread-stubs/manifests/0.5-1
  Already downloaded: /Users/cho-m/Library/Caches/Homebrew/downloads/daf0585704083a365a05b49b2a0078c97907e4a8b527f2a432b59a77805cf3f4--libpthread-stubs-0.5-1.bottle_manifest.json
  ==> Fetching dependencies for libpthread-stubs: pkgconf
  ==> Downloading https://ghcr.io/v2/homebrew/core/pkgconf/manifests/2.3.0
  Already downloaded: /Users/cho-m/Library/Caches/Homebrew/downloads/2f1a3719bf003aa9443a2e2e6af8e6441aa287088a24771231f191a9bcf36884--pkgconf-2.3.0.bottle_manifest.json
  ==> Fetching pkgconf
  ==> Downloading https://ghcr.io/v2/homebrew/core/pkgconf/blobs/sha256:9b44fe313d296fa10617d6b58ea1eab78bf217b6f00478ad98b01e0375475472
  Already downloaded: /Users/cho-m/Library/Caches/Homebrew/downloads/eed8a0a3462be8896edfce1cf6d726e4ebfd489cafecfb485f1b1b669a5d89af--pkgconf--2.3.0.sequoia.bottle.tar.gz
  ==> Fetching libpthread-stubs
  ==> Downloading https://ghcr.io/v2/homebrew/core/libpthread-stubs/blobs/sha256:303b8c21fc1b9322b6bd8f24e75a4e53a1c331d09b4f6271f75eba743d119819
  Already downloaded: /Users/cho-m/Library/Caches/Homebrew/downloads/623815c812e848149470976d73b58273ffb90c3873fe1ed3ec11f6d4a88c877f--libpthread-stubs--0.5.all.bottle.1.tar.gz
  ==> Installing dependencies for libpthread-stubs: pkgconf
  ==> Installing libpthread-stubs dependency: pkgconf
  ==> Downloading https://ghcr.io/v2/homebrew/core/pkgconf/manifests/2.3.0
  Already downloaded: /Users/cho-m/Library/Caches/Homebrew/downloads/2f1a3719bf003aa9443a2e2e6af8e6441aa287088a24771231f191a9bcf36884--pkgconf-2.3.0.bottle_manifest.json
  ==> Pouring pkgconf--2.3.0.sequoia.bottle.tar.gz
  🍺  /usr/local/Cellar/pkgconf/2.3.0: 25 files, 327.9KB
  ==> Installing libpthread-stubs
  ==> Pouring libpthread-stubs--0.5.all.bottle.1.tar.gz
  🍺  /usr/local/Cellar/libpthread-stubs/0.5: 6 files, 10.6KB
  ==> Running `brew cleanup libpthread-stubs`...
  Disable this behaviour by setting HOMEBREW_NO_INSTALL_CLEANUP.
  Hide these hints with HOMEBREW_NO_ENV_HINTS (see `man brew`).
  
  $ jq '.runtime_dependencies' /usr/local/Cellar/libpthread-stubs/0.5/INSTALL_RECEIPT.json
  [
    {
      "full_name": "pkgconf",
      "version": "2.3.0",
      "revision": 0,
      "pkg_version": "2.3.0",
      "declared_directly": false
    }
  ]

@cho-m sounds good, thanks!

Will rebase due to merging my Homebrew/brew PR which will probably cause syntax failure. Then can merge.

🤖 An automated task has requested bottles to be published to this PR.

is there any context as to why this was done? this seems to be the PR that deleted pkg-config formula, but it doesn't mention at all why it happened.

See discussion at #182175

The change shouldn't have any notable effect for the vast majority of users (except one incident with GitHub Actions that was caused by GitHub themselves which they have since fixed). We added aliases so brew install pkg-config still works and pkg-config still exists as an executable. Existing pkg-config installs install pkgconf automatically on brew upgrade, retaining full compatibility with any existing hardcoded paths (e.g. /opt/homebrew/opt/pkg-config/bin/pkg-config references).

If you face any regressions let us know.