feat(cli): generalize 'doom make codeowners'

- Adds -o/--file option,
- If -o/--file is passed a dash, print codeowners to stdout,
- Adds --dryrun option,
- Will accept literal string entries in doom-make-codeowners as
  standalone lines (useful for comments).

lisp/cli/make.el

@@ -10,8 +10,16 @@
 ;;
 ;;; Variables
 
-;; (defvar doom-make-codeowners ()
-;;   "TODO")
+(defvar doom-make-codeowners-file ".github/CODEOWNERS"
+  "Where to write the CODEOWNERS file, relative to the repo's toplevel.")
+
+(defvar doom-make-codeowners ()
+  "An alist of codeowners for this project.
+
+Each entry can either be a string (inserted verbatim, surrounded by newlines) or
+a pair of strings (in a cons cell) consisting of: (GLOB . CODEOWNERS).
+
+The contents of this variable are inserted in reverse.")
 
 
 ;;
@@ -21,23 +29,43 @@
   "(Re)Generate project files and boilerplate."
   :partial t)
 
-;; TODO Finish and generalize me
-(defstub! (make codeowners) ()
-  "TODO"
-  (print! (start "Generating CODEOWNERS file"))
-  (let ((codeowners (doom-path doom-emacs-dir ".github/CODEOWNERS")))
-    (with-temp-file codeowners
-      (insert-file-contents codeowners)
-      (when (re-search-forward "^# Don't edit this by hand!" nil t)
-        (goto-char (line-end-position))
-        (delete-region (point) (point-max))
-        (insert "\n")
-        (dolist (path (cdr (doom-module-load-path (list doom-modules-dir))))
-          (when (string-match "/modules/\\([^/]+\\)/\\([^/]+\\)/$" path)
-            (insert (format "%-35s @doomemacs/maintainers @doomemacs/%s-%s\n"
-                            (concat (substring (match-string-no-properties 0 path) 1) "*")
-                            (match-string-no-properties 1 path)
-                            (match-string-no-properties 2 path)))))))))
+(defcli! (make codeowners)
+    ((outfile  ("-o" "--file" (file stdout)) "Where to write the codeowners file")
+     (dryrun?  ("--dryrun")))
+  "Generate (or update) a CODEOWNERS file.
+
+By default, this means $GIT_WORK_TREE/.github/CODEOWNERS. This will throw an
+error if not run in a Git repo.
+
+OPTIONS:
+  -o, --file
+    Pass this option a dash to print the codeowners file to stdout."
+  (when dryrun?
+    (setq outfile "-")
+    (print! (warn "Running dry run; will only print to stdout:")))
+  (with-temp-buffer
+    (let ((codeowners-file
+           (cond ((equal outfile "-") nil)
+                 (outfile (expand-file-name outfile))
+                 ((file-name-concat (doom-git-toplevel) doom-make-codeowners-file)))))
+      (insert "# -*- mode: conf -*-\n"
+              "# Each line is a file pattern followed by one or more owners.\n"
+              "# This file was generated by 'doom make codeowners', do not edit it by hand.\n")
+      (dolist (entry (nreverse doom-make-codeowners))
+        (if (stringp entry)
+            (insert "\n" entry "\n")
+          (insert (car entry) " " (cdr entry) "\n")))
+      (insert "\n# End of CODEOWNERS")
+      (setq indent-tabs-mode nil) ; align w/ spaces, not tabs
+      (align-regexp (point-min) (point-max) "/\\(\\s-+\\)@" 1)
+      (if (null codeowners-file)
+          (print! "%s" (buffer-string))
+        (print! (start "%s codeowners file at: %s")
+                (if (file-exists-p codeowners-file)
+                    "Regenerated"
+                  "Generated")
+                (relpath codeowners-file))
+        (write-region (buffer-string) nil codeowners-file)))))
 
 ;; TODO Finish me
 (defstub! (make changelog))