fix(lib): package!: add :env property

Allows the association of arbitrary envvars or variables with the build
artifacts of a package. If they change, the package is rebuilt on the
next 'doom sync'. This is a temporary measure, which is why this is not
touted as a new feature. It will be replaced in v3.

lisp/doom-lib.el

@@ -1601,7 +1601,7 @@ For more about modules and flags, see `doom!'."
 ;;; `doom-package'
 
 (cl-defmacro package!
-    (name &rest plist &key built-in recipe ignore _type _pin _disable)
+    (name &rest plist &key built-in recipe ignore _type _pin _disable _env)
   "Declares a package and how to install it (if applicable).
 
 This macro is declarative and does not load nor install packages. It is used to
@@ -1638,6 +1638,9 @@ Accepts the following properties:
    inform help commands like `doom/help-packages' that this is a built-in
    package. If set to 'prefer, the package will not be installed if it is
    already provided by Emacs.
+ :env ALIST
+   Parameters and envvars to set while the package is building. If these values
+   change, the package will be rebuilt on next 'doom sync'.
 
 Returns t if package is successfully registered, and nil if it was disabled
 elsewhere."

lisp/lib/packages.el

@@ -965,8 +965,14 @@ Must be run from a magit diff buffer."
       (if-let* ((built
                  (doom-packages--with-recipes recipes (package local-repo recipe)
                    (let ((repo-dir (straight--repos-dir (or local-repo package)))
-                         (build-dir (straight--build-dir package)))
+                         (build-dir (straight--build-dir package))
+                         (build-file ".doompackage"))
                      (unless force-p
+                       ;; Ensure packages w/ a changed :env are rebuilt
+                       (when-let* ((plist (alist-get (intern package) doom-packages)))
+                         (unless (equal (plist-get plist :env)
+                                        (doom-file-read (doom-path build-dir build-file) :by 'read :noerror t))
+                           (puthash package t straight--packages-to-rebuild)))
                        ;; Ensure packages w/ outdated files/bytecode are rebuilt
                        (let* ((build (if (plist-member recipe :build)
                                          (plist-get recipe :build)
@@ -1005,7 +1011,25 @@ Must be run from a magit diff buffer."
                                               (print! (item "%s: pinned to %s") package pin)
                                             (when commit
                                               (print! (item "%s: checked out %s") package commit)))))
-                                      straight-vc-git-post-clone-hook)))
+                                      straight-vc-git-post-clone-hook))
+                               (straight-use-package-prepare-functions
+                                (cons (lambda (package &rest _)
+                                        (when-let* ((plist (alist-get (intern package) doom-packages))
+                                                    (env (plist-get plist :env)))
+                                          (cl-loop for (var . val) in env
+                                                   if (and (symbolp var)
+                                                           (string-prefix-p "_" (symbol-name var)))
+                                                   do (set-default var val)
+                                                   else if (and (stringp var) val)
+                                                   do (setenv var val))))
+                                      straight-use-package-prepare-functions))
+                               (straight-use-package-post-build-functions
+                                (cons (lambda (package &rest _)
+                                        (when-let* ((plist (alist-get (intern package) doom-packages))
+                                                    (env (plist-get plist :env)))
+                                          (with-temp-file (straight--build-file package build-file)
+                                            (prin1 env (current-buffer)))))
+                                      straight-use-package-post-build-functions)))
                            (straight-use-package (intern package)))
                        (error
                         (signal 'doom-package-error (list package e))))))))

lisp/lib/profiles.el

@@ -61,6 +61,7 @@ Can be changed externally by setting $DOOMPROFILELOADFILE.")
 ;;; Profile storage variables
 (defvar doom-profile-generators
   '(("05-vars.auto.el"              doom-profile--generate-vars               doom--startup-vars)
+    ("20-package-envs.auto.el"      doom-profile--generate-package-envs)
     ("80-loaddefs.auto.el"          doom-profile--generate-loaddefs-doom      doom--startup-loaddefs-doom)
     ("90-loaddefs-packages.auto.el" doom-profile--generate-loaddefs-packages  doom--startup-loaddefs-packages)
     ("95-modules.auto.el"           doom-profile--generate-load-modules       doom--startup-modules))
@@ -422,6 +423,16 @@ caches them in `doom--profiles'. If RELOAD? is non-nil, refresh the cache."
                    (mapcan #'doom-glob doom-autoloads-files))
            nil)))))
 
+(defun doom-profile--generate-package-envs ()
+  (cl-loop for (_ . plist) in doom-packages
+           if (plist-get plist :env)
+           append (cl-loop for (var . val) in it
+                           if (and (stringp var) val)
+                           collect `(setenv ,var ,val)
+                           else if (and (symbolp var)
+                                        (string-prefix-p "_" (symbol-name var)))
+                           collect `(setq-default ,var ,val))))
+
 (defun doom-profile--generate-loaddefs-packages ()
   `((defun doom--startup-loaddefs-packages ()
       (let ((load-in-progress t))