feat(wpcarro/emacs): Test that my Emacs can initialize

...without warnings, errors.

This was previously a step in my buildkite instance, but I'm no longer
supporting that (in favor of the TVL one).

Change-Id: Ifed39aef248b21a1eb5a6c9d8427ebe6996abc3a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5103
Tested-by: BuildkiteCI
Reviewed-by: wpcarro <wpcarro@gmail.com>
Autosubmit: wpcarro <wpcarro@gmail.com>

users/wpcarro/emacs/ci.el

@@ -0,0 +1,44 @@
+;; This script initializes Emacs and exits with either a zero or non-zero status
+;; depending on whether or not Emacs initialized without logging warnings or
+;; encountering errors.
+;;
+;; This script reads the location of init.el as the last argument in `argv'.
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Dependencies
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(require 'prelude)
+(require 'f)
+(require 'dash)
+(require 'buffer)
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Script
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(defvar init-el-path (-last-item argv)
+  "Path to the init.el file that this script attempts to load.")
+
+(prelude-assert (f-exists? init-el-path))
+
+(condition-case err
+    (load init-el-path)
+  (error
+   (message "Encountered an error while attempting to load init.el: %s" err)
+   (kill-emacs 1)))
+
+(when (buffer-exists? "*Errors*")
+  (progn
+    (with-current-buffer "*Errors*"
+      (message "Encountered errors in *Errors* buffer: %s" (buffer-string)))
+    (kill-emacs 1)))
+
+(when (buffer-exists? "*Warnings*")
+  (progn
+    (with-current-buffer "*Warnings*"
+      (message "Encountered warnings in *Warnings* buffer: %s" (buffer-string)))
+    (kill-emacs 1)))
+
+(message "Successfully init'd Emacs without encountering errors or warnings!")
+(kill-emacs 0)

users/wpcarro/emacs/default.nix

@@ -165,25 +165,34 @@ let
         --load ${initEl} \
         "$@"
     '';
-in {
-  inherit initEl withEmacsPath;
 
-  # I need to start my Emacs from CI without the call to `--load ${initEl}`.
-  runScript = { script }:
-    writeShellScript "run-emacs-script" ''
-      export PATH="${emacsBinPath}:$PATH"
-      export EMACSLOADPATH="${wpcDir}:${vendorDir}:${wpcarrosEmacs.deps}/share/emacs/site-lisp"
-      exec ${wpcarrosEmacs}/bin/emacs \
-        --no-site-file \
-        --no-site-lisp \
-        --no-init-file \
-        --script ${script} \
-        "$@"
+  # I need this to start my Emacs from CI without the call to
+  # `--load ${initEl}`.
+  runScript = script: writeShellScript "run-emacs-script" ''
+    export PATH="${emacsBinPath}:$PATH"
+    export EMACSLOADPATH="${loadPath}"
+    exec ${wpcarrosEmacs}/bin/emacs \
+      --no-site-file \
+      --no-site-lisp \
+      --no-init-file \
+      --script ${script} \
+      "$@"
     '';
 
+in {
+  inherit withEmacsPath;
+
   nixos = withEmacsPath {
     emacsBin = "${wpcarrosEmacs}/bin/emacs";
   };
 
-  meta.targets = [ "nixos" ];
+  meta = {
+    targets = [ "nixos" ];
+    extraSteps = [
+      {
+        label = ":gnu: initialize Emacs";
+        command = "${runScript ./ci.el} ${./.emacs.d/init.el}";
+      }
+    ];
+  };
 }