Handle multibyte/binary data in sideloader, start tooling sideloader

When serving base64-encoded resources to the sideloader we need to make sure we
encode the contents exactly as they are byte for byte, instead of letting Emacs
apply character encoding and such.

When starting the sideloader also start one on the tooling session.

Author: plexus

CHANGELOG.md

@@ -12,6 +12,7 @@
 * [#3020](https://github.com/clojure-emacs/cider/issues/3020): Fix session linking on Windows, e.g. when jumping into a library on the classpath.
 * [#3031](https://github.com/clojure-emacs/cider/pull/3031): Fix `cider-eval-defun-up-to-point` failing to match delimiters correctly in some cases, resulting in reader exceptions.
 * [#3039](https://github.com/clojure-emacs/cider/pull/3039): Allow starting the sideloader for the tooling session
+* [#3031](https://github.com/clojure-emacs/cider/pull/3041): Handle binary/multibyte data when serving sideloaded resources
 
 ## 1.1.1 (2021-05-24)
 

cider-eval.el

@@ -189,14 +189,29 @@ When invoked with a prefix ARG the command doesn't prompt for confirmation."
 
 ;;; Sideloader
 
-(defvar cider-sideloader-dir (file-name-directory load-file-name))
+(defvar cider-sideloader-dirs
+  (list (file-name-directory load-file-name))
+  "Directories where we look for resources requested by the sideloader")
+
+;; based on f-read-bytes
+(defun cider-read-bytes (path)
+  "Read binary data from PATH.
+Return the binary data as unibyte string."
+  (with-temp-buffer
+    (set-buffer-multibyte nil)
+    (setq buffer-file-coding-system 'binary)
+    (insert-file-contents-literally path nil)
+    (buffer-substring-no-properties (point-min) (point-max))))
 
 (defun cider-provide-file (file)
   "Provide FILE in a format suitable for sideloading."
-  (let ((file (expand-file-name file cider-sideloader-dir)))
-    (if (file-exists-p file)
-        (with-current-buffer (find-file-noselect file)
-          (base64-encode-string (substring-no-properties (buffer-string)) 'no-line-breaks))
+  (let ((file (seq-find
+               #'file-exists-p
+               (seq-map (lambda (dir)
+                          (expand-file-name file dir))
+                        cider-sideloader-dirs))))
+    (if file
+        (base64-encode-string (cider-read-bytes file) 'no-line-breaks)
       ;; if we can't find the file we should return an empty string
       (base64-encode-string ""))))
 
@@ -235,7 +250,8 @@ If CONNECTION is nil, use `cider-current-repl'."
 If CONNECTION is nil, use `cider-current-repl'."
   (interactive)
   (message "Starting nREPL's sideloader")
-  (cider-request:sideloader-start connection))
+  (cider-request:sideloader-start connection)
+  (cider-request:sideloader-start connection 'tooling))
 
 
 ;;; Dealing with compilation (evaluation) errors and warnings