fix(cli): rewrite 'doom sync'; deprecate 'doom build'

This changes 'doom sync' to be smarter about responding to changed
package recipes/pins, changes in Emacs version, or instances where the user
has copied a config to a new system.

In all these cases, the user would formerly have to know about a
specific combination of 'doom sync -u' and 'doom build' to ensure Doom
is in a good state. With this change, 'doom sync' handles all these
cases.

Also, 'doom build' is now deprecated (and 'doom sync' now has a
--rebuild option to mimic its old behavior).

Also also, sometimes, a package may silently fail when cloned (which
used to result in an empty repo). Now, if this is detected, cloning will
be re-attempted up to 3 times before aborting with much more visible
error.

Note: these are stopgap solutions, until v3 is finished.

lisp/cli/sync.el

@@ -14,18 +14,21 @@
 (defvar doom-before-sync-hook ()
   "Hooks run before 'doom sync' synchronizes the user's config with Doom.")
 
+(defvar doom-cli-sync-info-file (file-name-concat doom-profile-data-dir "sync"))
+
 
 ;;
 ;;; Commands
 
-(defcli-alias! (:before (sync s)) (:before build))
-
 (defcli! ((sync s))
     ((noenvvar? ("-e") "Don't regenerate the envvar file")
-     (noelc?    ("-c") "Don't recompile config")
-     (update?   ("-u") "Update installed packages after syncing")
+     (update?   ("-u") "Update all installed packages after syncing")
+     (noupdate? ("-U") "Don't update any packages")
      (purge?    ("-p") "Purge orphaned package repos & regraft them")
-     (jobs      ("-j" "--jobs" num) "How many CPUs to use for native compilation"))
+     (jobs      ("-j" "--jobs" num) "How many threads to use for native compilation")
+     (rebuild?  ("-b" "--rebuild") "Rebuild, compile, & symlink installed packages")
+     (auto?     ("-B") "Rebuild packages, but only if necessary")
+     &context context)
   "Synchronize your config with Doom Emacs.
 
 This is the equivalent of running autoremove, install, autoloads, then
@@ -33,8 +36,10 @@ recompile. Run this whenever you:
 
   1. Modify your `doom!' block,
   2. Add or remove `package!' blocks to your config,
-  3. Add or remove autoloaded functions in module autoloaded files.
-  4. Update Doom outside of Doom (e.g. with git)
+  3. Add or remove autoloaded functions in module autoloaded files,
+  4. Update Doom outside of Doom (e.g. with git),
+  5. Move your Doom config (either $EMACSDIR or $DOOMDIR) to a new location.
+  6. When you up (or down) grade Emacs itself.
 
 It will ensure that unneeded packages are removed, all needed packages are
 installed, autoloads files are up-to-date and no byte-compiled files have gone
@@ -47,26 +52,47 @@ OPTIONS:
   :benchmark t
   (when (doom-profiles-bootloadable-p)
     (call! '(profiles sync "--reload")))
-  (run-hooks 'doom-before-sync-hook)
-  (add-hook 'kill-emacs-hook #'doom-sync--abort-warning-h)
+  (when (doom-cli-context-suppress-prompts-p context)
+    (setq auto? t))
   (when jobs
     (setq native-comp-async-jobs-number (truncate jobs)))
-  (print! (start "Synchronizing %S profile..." )
-          (or (car doom-profile) "default"))
+  (run-hooks 'doom-before-sync-hook)
+  (add-hook 'kill-emacs-hook #'doom-sync--abort-warning-h)
+  (print! (item "Using Emacs %s @ %s") emacs-version (path invocation-directory invocation-name))
+  (print! (start "Synchronizing %S profile..." ) (or (car doom-profile) "default"))
   (unwind-protect
       (print-group!
-       (when (and (not noenvvar?)
-                  (file-exists-p doom-env-file))
-         (call! '(env)))
-       (doom-packages-install)
-       (doom-packages-build)
-       (when update?
-         (doom-packages-update))
-       (doom-packages-purge purge? purge? purge? purge? purge?)
-       (when (doom-profile-generate)
-         (print! (item "Restart Emacs or use 'M-x doom/reload' for changes to take effect"))
-         (run-hooks 'doom-after-sync-hook))
-       t)
+        ;; If the user has up/downgraded Emacs since last sync, or copied their
+        ;; config to a different system, then their packages need to be
+        ;; recompiled. This is necessary because Emacs byte-code is not
+        ;; necessarily back/forward compatible across major versions, and many
+        ;; packages bake in hardcoded data at compile-time.
+        (pcase-let ((`(,old-version . ,old-host) (doom-file-read doom-cli-sync-info-file :by 'read :noerror t))
+                    (to-rebuild nil))
+          (when (and old-version (not (equal old-version emacs-version)))
+            (print! (warn "Emacs version has changed since last sync (from %s to %s)") old-version emacs-version)
+            (setq to-rebuild t))
+          (when (and old-host (not (equal old-host (system-name))))
+            (print! (warn "Your system has changed since last sync"))
+            (setq to-rebuild t))
+          (when (and to-rebuild (not auto?))
+            (or (y-or-n-p
+                 (format! "  %s" "Your installed packages will need to be recompiled. Do so now?"))
+                (exit! 0))
+            (setq rebuild? t)))
+        (when (and (not noenvvar?)
+                   (file-exists-p
+                    (file-name-concat doom-profile-dir
+                                      doom-profile-env-file-name)))
+          (call! '(env)))
+        (doom-packages-ensure rebuild?)
+        (unless noupdate? (doom-packages-update (not update?)))
+        (doom-packages-purge purge? purge? purge? purge? purge?)
+        (when (doom-profile-generate)
+          (print! (item "Restart Emacs or use 'M-x doom/reload' for changes to take effect"))
+          (run-hooks 'doom-after-sync-hook))
+        (with-temp-file doom-cli-sync-info-file (prin1 (cons emacs-version (system-name)) (current-buffer)))
+        t)
     (remove-hook 'kill-emacs-hook #'doom-sync--abort-warning-h)))