[Bug]: Finding root of nested alire project

[simonjwright]

Environment

• OS and Version: macOS 15.0.1 (arm64)
• IDE Version: Emacs 29.3, eglot 1.17, ALS 25.0.20240915
• Ada & SPARK Extension Version: 14.2.0

Bug Summary and Reproducer

Bug Summary: I have a project where the main crate directory has a subdirectory test/ containing a test crate.

If I open a file test/src/vectors_test.adb, ALS log shows

[ALS.MAIN] In Message_Handler Text_Document_Did_Open URI:
[ALS.MAIN] file:///Users/simon/Developer/minimal_containers/test/src/maps_tests.adb
[ALS.MAIN] Looking for a project... Root:
[ALS.MAIN] file:///Users/simon/Developer/minimal_containers
[ALS.MAIN] Check alire:
[ALS.MAIN] Project:
[ALS.MAIN] minimal_containers.gpr

Steps to reproduce: see above.

Expected behavior: It should find the immediate test/ directory.

Configuration and Logs

[ALS.MAIN] In Message_Handler Text_Document_Did_Open URI:
[ALS.MAIN] file:///Users/simon/Developer/minimal_containers/test/src/maps_tests.adb
[ALS.MAIN] Looking for a project... Root:
[ALS.MAIN] file:///Users/simon/Developer/minimal_containers
[ALS.MAIN] Check alire:
[ALS.MAIN] Project:
[ALS.MAIN] minimal_containers.gpr

Other VS Code Extensions

No response

Additional context

No response

[simonjwright]

This isn’t a bug, nor is it an issue with ALS!

eglot uses project, and project’s only provided root-finding method is to look for a repo. We need to tell it to look first for alire.toml, next for *.gpr, and then for a repo.

[eliericha]

I'm not familiar with eglot, but I can say that upon startup, if ALS finds a alire.toml at the root workspace, it queries Alire for the project to use.

In your project if ALS was started at the root of the repository, it will use the root alire.toml even if you open a source file from the test/ sub-directory.

Is eglot able to intervene earlier to start the ALS under the test/ sub-directory when relevant?

[simonjwright]

My use case is that the Alire crate’s top level (the repo) has a sub-crate containing the test suite. So when I open a file under the test crate, I want ALS to find the sub-crate, not the main one, which is indeed the default in eglot.

This below sets project.el to look first for alire.toml, if not found for *.gpr, if not found for a repo. It works a treat with ALS!

(defun ada-mode--find-alire (dir)
  (let ((alire (locate-dominating-file dir "alire.toml")))
    (if alire
      (cons 'transient alire)
      nil)))

(defun ada-mode--find-gpr (dir)
  (let ((gpr (locate-dominating-file
              dir
              (lambda (dir) (directory-files dir nil "gpr"))
              )))
    (if gpr
      (cons 'transient gpr)
      nil)))

(use-package project
  :config
  ;; last-in, first-used
  (add-hook 'project-find-functions #'ada-mode--find-gpr)
  (add-hook 'project-find-functions #'ada-mode--find-alire)
  )