*cider-error*: open a given exception in the Inspector by clicking it

Fixes #3565

Author: vemv

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## master (unreleased)
 
+### New features
+
+- [#3565](https://github.com/clojure-emacs/cider/issues/3565): [`*cider-error*`](https://docs.cider.mx/cider/usage/dealing_with_errors.html#inspector-integration): open a given Exception in the [Inspector](https://docs.cider.mx/cider/debugging/inspector.html) by clicking it, or hitting <kbd>p</kbd>.
+
 ### Changes
 
 - CIDER [Inspector](https://docs.cider.mx/cider/debugging/inspector.html): display Java class/method/field info when available.

cider-inspector.el

@@ -236,6 +236,17 @@ See `cider-sync-request:inspect-push' and `cider-inspector--render-value'"
       (cider-inspector--render-value result 'v2)
       (cider-inspector-next-inspectable-object 1))))
 
+(defun cider-inspector-inspect-last-exception (index)
+  "Inspects the exception in the cause stack identified by INDEX."
+  (interactive)
+  (cl-assert (numberp index))
+  (setq cider-inspector--current-repl (cider-current-repl))
+  (let ((result (cider-sync-request:inspect-last-exception index 'v2)))
+    (when (nrepl-dict-get result "value")
+      (push (point) cider-inspector-location-stack)
+      (cider-inspector--render-value result 'v2)
+      (cider-inspector-next-inspectable-object 1))))
+
 (defun cider-inspector-previous-sibling ()
   "Inspect the previous sibling value within a sequential parent.
 See `cider-sync-request:inspect-previous-sibling' and `cider-inspector--render-value'"
@@ -387,6 +398,19 @@ instead of just its \"value\" entry."
         result
       (nrepl-dict-get result "value"))))
 
+;;;###autoload
+(defun cider-sync-request:inspect-last-exception (index &optional v2)
+  "Inspects the exception in the cause stack identified by INDEX,
+V2 indicates if the entire response should be returned
+instead of just its \"value\" entry."
+  (cl-assert (numberp index))
+  (let ((result (thread-first `("op" "inspect-last-exception"
+                                "index" ,index)
+                              (cider-nrepl-send-sync-request cider-inspector--current-repl))))
+    (if v2
+        result
+      (nrepl-dict-get result "value"))))
+
 (defun cider-sync-request:inspect-next-sibling (&optional v2)
   "Inspect the next sibling value within a sequential parent,
 V2 indicates if the entire response should be returned

cider-stacktrace.el

@@ -799,16 +799,48 @@ the NAME.  The whole group is prefixed by string INDENT."
             (cider-stacktrace--insert-named-group indent2 "extras: \n")
             (cider-stacktrace-emit-indented extra (concat indent2 "  ") nil t)))))))
 
-(defun cider-stacktrace-render-cause (buffer cause num note)
-  "Emit into BUFFER the CAUSE NUM, exception class, message, data, and NOTE."
+(declare-function cider-inspector-inspect-last-exception "cider-inspector")
+
+(defun cider-stacktrace--inspect-class (event)
+  "Mouse handler for EVENT."
+  (interactive "e")
+  (let* ((pos (posn-point (event-end event)))
+         (window (posn-window (event-end event)))
+         (buffer (window-buffer window))
+         (inspect-index (with-current-buffer buffer
+                          (get-text-property pos 'inspect-index))))
+    (cider-inspector-inspect-last-exception inspect-index)))
+
+(defun cider-stacktrace--inspect-class-kbd ()
+  "Keyboard handler."
+  (interactive)
+  (when-let ((inspect-index (get-text-property (point) 'inspect-index)))
+    (cider-inspector-inspect-last-exception inspect-index)))
+
+(defvar cider-stacktrace-exception-map
+  (let ((map (make-sparse-keymap)))
+    (define-key map [mouse-1] #'cider-stacktrace--inspect-class)
+    (define-key map (kbd "p") #'cider-stacktrace--inspect-class-kbd)
+    map))
+
+(defun cider-stacktrace-render-cause (buffer cause num note &optional inspect-index)
+  "Emit into BUFFER the CAUSE NUM, exception class, message, data, and NOTE,
+make INSPECT-INDEX actionable if present."
   (with-current-buffer buffer
     (nrepl-dbind-response cause (class message data spec stacktrace)
       (let ((indent "   ")
             (class-face 'cider-stacktrace-error-class-face)
             (message-face 'cider-stacktrace-error-message-face))
         (cider-propertize-region `(cause ,num)
           ;; Detail level 0: exception class
-          (cider-propertize-region '(detail 0)
+          (cider-propertize-region `(detail
+                                     0
+
+                                     inspect-index
+                                     ,inspect-index
+
+                                     keymap
+                                     ,cider-stacktrace-exception-map)
             (insert (format "%d. " num)
                     (propertize note 'font-lock-face 'font-lock-comment-face) " "
                     (propertize class 'font-lock-face class-face)
@@ -885,10 +917,11 @@ through the `cider-stacktrace-suppressed-errors' variable."
         (cider-stacktrace-render-suppression-toggle buffer error-types)
         (insert "\n\n"))
       ;; Stacktrace exceptions & frames
-      (let ((num (length causes)))
+      (let* ((causes-length (length causes))
+             (num causes-length))
         (dolist (cause causes)
-          (let ((note (if (= num (length causes)) "Unhandled" "Caused by")))
-            (cider-stacktrace-render-cause buffer cause num note)
+          (let ((note (if (= num causes-length) "Unhandled" "Caused by")))
+            (cider-stacktrace-render-cause buffer cause num note (- causes-length num))
             (setq num (1- num))))))
     (cider-stacktrace-initialize causes)
     (font-lock-refresh-defaults)))

doc/modules/ROOT/pages/usage/dealing_with_errors.adoc

@@ -295,3 +295,21 @@ Cider recognizes stacktraces printed in the following formats:
   buffer. When `cider-stacktrace-analyze-at-point` fails to detect the
   stacktrace, `cider-stacktrace-analyze-in-region` can be used to
   select the stacktrace manually.
+
+== Inspector integration
+
+Within `*cider-error*`, when clicking directly a top-level exception (any of them in the cause chain),
+that specific exception will be inspected with the CIDER xref:debugging/inspector.adoc[Inspector].
+
+This allows you to better understand intrincate `ex-data`.
+
+This clicking is defined and customizable in `cider-stacktrace-exception-map`, which has the following defaults:
+
+=== Keybindings
+
+|===
+| Action | Description
+
+| kbd:[click] or kbd:[p] 
+| Open the given exception in the Inspector.
+|===