[Fix #2907] Provide ability to customise cljfmt code formatting (#2982)

Author: iarenaza

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### New features
 
 * [#2930](https://github.com/clojure-emacs/cider/issues/2930): Add new customization variable `cider-test-default-include-selectors` and `cider-test-default-exclude-selectors` for specifying default test selectors when running commands such as `cider-test-run-ns-tests`.
+* [#2907](https://github.com/clojure-emacs/cider/issues/2907): Add new customization variable `cider-format-code-options` to specify options used by `cljfmt` to format code when running commands `cider-format-buffer`, `cider-format-region`  and `cider-format-defun`.
 * [#3002](https://github.com/clojure-emacs/cider/pull/3002): [Inspector] Make collection member truncation limits configurable.
 
 ### Bugs fixed

cider-client.el

@@ -210,6 +210,47 @@ buffer, defaults to (cider-current-repl)."
 If NS is non-nil, include it in the eval request."
   (nrepl-sync-request:eval input (or connection (cider-current-repl nil 'ensure)) ns))
 
+(defcustom cider-format-code-options nil
+  "A map of options that will be passed to `cljfmt' to format code.
+Assuming this is the Clojure map you want to use as `cljfmt options':
+
+  {:indents {org.me/foo [[:inner 0]]}
+   :alias-map {\"me\" \"org.me\"}}
+
+you need to encode it as the following plist:
+
+  '((\"indents\" ((\"org.me/foo\" ((\"inner\" 0))))) (\"alias-map\" ((\"me\" \"org.me\"))))"
+  :type 'list
+  :group 'cider
+  :package-version '(cider . "1.0.0"))
+
+(defun cider--nrepl-format-code-request-map (&optional format-options)
+  "Map to merge into requests that require code formatting.
+If non-nil, FORMAT-OPTIONS specifies the options cljfmt will use to format
+the code.  See `cider-format-code-options` for details."
+  (when format-options
+    (let* ((indents-dict (when (assoc "indents" format-options)
+                           (thread-last
+                               (cadr (assoc "indents" format-options))
+                             (map-pairs)
+                             (seq-mapcat #'identity)
+                             (apply #'nrepl-dict))))
+           (alias-map-dict (when (assoc "alias-map" format-options)
+                             (thread-last
+                                 (cadr (assoc "alias-map" format-options))
+                               (map-pairs)
+                               (seq-mapcat #'identity)
+                               (apply #'nrepl-dict)))))
+      (thread-last
+          (map-merge 'list
+                     (when indents-dict
+                       `(("indents" ,indents-dict)))
+                     (when alias-map-dict
+                       `(("alias-map" ,alias-map-dict))))
+        (map-pairs)
+        (seq-mapcat #'identity)
+        (apply #'nrepl-dict)))))
+
 (defcustom cider-print-fn 'pprint
   "Sets the function to use for printing.
 
@@ -712,12 +753,19 @@ The result entries are relative to the classpath."
     (cider-nrepl-send-sync-request)
     (nrepl-dict-get "fn-deps")))
 
-(defun cider-sync-request:format-code (code)
-  "Perform nREPL \"format-code\" op with CODE."
-  (thread-first `("op" "format-code"
-                  "code" ,code)
-    (cider-nrepl-send-sync-request)
-    (nrepl-dict-get "formatted-code")))
+(defun cider-sync-request:format-code (code &optional format-options)
+  "Perform nREPL \"format-code\" op with CODE.
+FORMAT-OPTIONS is an optional configuration map for cljfmt."
+  (let* ((request `("op" "format-code"
+                    "options" ,(cider--nrepl-format-code-request-map format-options)
+                    "code" ,code))
+         (response (cider-nrepl-send-sync-request request))
+         (err (nrepl-dict-get response "err")))
+    (when err
+      ;; err will be a stacktrace with a first line that looks like:
+      ;; "clojure.lang.ExceptionInfo: Unmatched delimiter ]"
+      (error (car (split-string err "\n"))))
+    (nrepl-dict-get response "formatted-code")))
 
 (defun cider-sync-request:format-edn (edn right-margin)
   "Perform \"format-edn\" op with EDN and RIGHT-MARGIN."

cider-format.el

@@ -85,7 +85,9 @@ Uses the following heuristic to try to maintain point position:
 START and END represent the region's boundaries."
   (interactive "r")
   (cider-ensure-connected)
-  (cider--format-region start end #'cider-sync-request:format-code))
+  (cider--format-region start end
+                        (lambda (buf)
+                          (cider-sync-request:format-code buf cider-format-code-options))))
 
 
 ;;; Format defun
@@ -114,7 +116,8 @@ of the buffer into a formatted string."
   (interactive)
   (check-parens)
   (cider-ensure-connected)
-  (cider--format-buffer #'cider-sync-request:format-code))
+  (cider--format-buffer (lambda (buf)
+                          (cider-sync-request:format-code buf cider-format-code-options))))
 
 
 ;;; Format EDN