Implement daisy-chaining for CLI sessions

elisp lacks an execv implementation (or mature subprocess library), so
we exploit some splenderiffic hackery to get Emacs to execute arbitrary
shell commands after a 'doom ...' command completes. This allows us to
daisy chain doom commands in distinct sessions (wonderful for reloading
doom after a 'doom upgrade', which we do). This minimizes errors when a
'doom upgrade' pulls in breaking changes to Doom's CLI.

We also bring 'doom run' into elisp, since this new functionality
enables us to.

bin/doom

@@ -1,13 +1,15 @@
 #!/usr/bin/env sh
 :; ( echo "$EMACS" | grep -q "term" ) && EMACS=emacs || EMACS=${EMACS:-emacs} # -*-emacs-lisp-*-
 :; command -v $EMACS >/dev/null || { >&2 echo "Can't find emacs in your PATH"; exit 1; }
-:; VERSION=$($EMACS --version | head -n1)
+:; _VERSION=$($EMACS --version | head -n1)
-:; case "$VERSION" in *\ 2[0-5].[0-9]) echo "Detected Emacs $VERSION"; echo "Doom only supports Emacs 26.1 and newer"; echo; exit 2 ;; esac
+:; case "$_VERSION" in *\ 2[0-5].[0-9]) echo "Detected Emacs $_VERSION"; echo "Doom only supports Emacs 26.1 and newer"; echo; exit 2 ;; esac
-:; DOOMBASE="$(dirname "$0")/.."
+:; _DOOMBASE="${EMACSDIR:-$(dirname "$0")/..}"
-:; [ "$1" = -d ] || [ "$1" = --debug ] && { shift; export DEBUG=1; }
+:; _DOOMPOST="$_DOOMBASE/.local/.doom.sh"
-:; [ "$1" = run ] && { cd "$DOOMBASE"; shift; exec $EMACS -q --no-splash -l init.el -f doom-run-all-startup-hooks-h "$@"; exit 0; }
+:; rm -f "$_DOOMPOST"
-:; exec $EMACS --no-site-file --script "$0" -- "$@"
+:; $EMACS --no-site-file --script "$0" -- "$@"
-:; exit 0
+:; CODE=$?
+:; [ -x "$_DOOMPOST" ] && PATH="$_DOOMBASE/bin:$PATH" "$_DOOMPOST" "$0" "$@"
+:; exit $CODE
 
 (let* ((loaddir (file-name-directory (file-truename load-file-name)))
        (emacsdir (getenv "EMACSDIR"))
@@ -46,7 +48,7 @@ with a different private module."
     :bare t
     (when emacsdir
       (setq user-emacs-directory (file-name-as-directory emacsdir))
-      (print! (info "EMACSDIR=%s") localdir))
+      (print! (info "EMACSDIR=%s") emacsdir))
     (when doomdir
       (setenv "DOOMDIR" (file-name-as-directory doomdir))
       (print! (info "DOOMDIR=%s") localdir))

core/cli/upgrade.el

@@ -15,16 +15,19 @@ following shell commands:
     bin/doom update"
   :bare t
   (let ((doom-auto-discard force-p))
-    (if (delq
+    (cond
-         nil (list
+     (packages-only-p
-              (unless packages-only-p
+      (doom-cli-execute "sync" "-u")
-                (doom-cli-upgrade doom-auto-accept doom-auto-discard))
+      (print! (success "Finished upgrading Doom Emacs")))
-              (doom-cli-execute "sync")
+
-              (when (doom-cli-packages-update)
+     ((not (doom-cli-upgrade doom-auto-accept doom-auto-discard))
-                (doom-autoloads-reload)
+      (print! "Nothing to do. Doom is up-to-date!"))
-                t)))
+
-        (print! (success "Done! Restart Emacs for changes to take effect."))
+     (t
-      (print! "Nothing to do. Doom is up-to-date!"))))
+      ;; Reload Doom's CLI & libraries, in case there were any
+      ;; upstream changes. Major changes will still break, however
+      (print! (info "Reloading Doom Emacs"))
+      (doom-cli-execute-after "doom" "upgrade" "-p" (if force-p "-f"))))))
 
 
 ;;
@@ -113,24 +116,6 @@ following shell commands:
                                 (equal (vc-git--rev-parse "HEAD") new-rev))
                      (error "Failed to check out %s" (substring new-rev 0 10)))
                    (print! (info "%s") (cdr result))
-
+                   t))))))
-                   ;; Reload Doom's CLI & libraries, in case there were any
-                   ;; upstream changes. Major changes will still break, however
-                   (condition-case-unless-debug e
-                       (progn
-                         (mapc (lambda (f) (load (symbol-name f)))
-                               '(core core-lib
-                                      core-cli
-                                      core-modules
-                                      core-packages))
-                         (doom-initialize 'force))
-                     (error
-                      (signal 'doom-error
-                              (list "Could not reload new version of Doom"
-                                    "Try running 'doom upgrade' again"
-                                    e))))
-
-                   (print! (success "Finished upgrading Doom Emacs")))
-                  t)))))
         (ignore-errors
           (doom-call-process "git" "remote" "remove" doom-repo-remote))))))

core/core-cli.el

@@ -166,6 +166,24 @@ COMMAND, and passes ARGS to it."
                (doom--cli-process cli (remq nil args)))
     (user-error "Couldn't find any %S command" command)))
 
+(defun doom-cli-execute-after (&rest args)
+  "Execute shell command ARGS after this CLI session quits.
+
+This is particularly useful when the capabilities of Emacs' batch terminal are
+insufficient (like opening an instance of Emacs, or reloading Doom after a 'doom
+upgrade')."
+  (let ((post-script (concat doom-local-dir ".doom.sh")))
+    (with-temp-file post-script
+      (insert "#!/usr/bin/env sh\n"
+              "rm -f " (prin1-to-string post-script) "\n"
+              "exec " (mapconcat #'shell-quote-argument (remq nil args) " ")
+              "\n"))
+    (let* ((current-mode (file-modes post-script))
+           (add-mode (logand ?\111 (default-file-modes))))
+      (or (/= (logand ?\111 current-mode) 0)
+          (zerop add-mode)
+          (set-file-modes post-script (logior current-mode add-mode))))))
+
 (defmacro defcli! (name speclist &optional docstring &rest body)
   "Defines a CLI command.
 
@@ -423,7 +441,9 @@ All arguments are passed on to Emacs.
 
 WARNING: this command exists for convenience and testing. Doom will suffer
 additional overhead by being started this way. For the best performance, it is
-best to run Doom out of ~/.emacs.d and ~/.doom.d."))
+best to run Doom out of ~/.emacs.d and ~/.doom.d."
+    (apply #'doom-cli-execute-after invocation-name args)
+    nil))
 
 (provide 'core-cli)
 ;;; core-cli.el ends here