Register process sentinel to log status on process exit

Enables lexical scoping, which is needed for closures to work in sentinel callbacks.

The complexity in this handler is due to the need to ensure that any sentinels
already registered for the process are correctly preserved.

For example, I personally have a hook for term-mode, which registers a sentinel
to prompt for closing the buffer on process exit. Without this logic the logger
for the completion status would override my handler completely.

Author: Daniel Dinnyes

conda.el

@@ -1,3 +1,4 @@
+;; -*- lexical-binding: t; -*-
 ;;; conda.el --- Work with your conda environments
 
 ;; Copyright (C) 2016-2024 Rami Chowdhury
@@ -705,6 +706,15 @@ environment YAML file or similar at the project level."
       (if conda-message-on-environment-switch
           (message "No Conda environment found for <%s>" (buffer-file-name))))))
 
+(defun conda--env-process-exit-message (op env-name &optional callback)
+  ;; capture dynamically scoped closures
+  (lambda (proc _event)
+    (when (memq (process-status proc) '(exit signal))
+      (if (zerop (process-exit-status proc))
+          (message "Finished %s Conda environment <%s>" op env-name)
+        (message "Error while %s Conda environment <%s>" op env-name)))
+    (when callback (funcall callback proc _event))))
+
 ;;;###autoload
 (defun conda-env-yaml-process-for-buffer (&optional remove env-file)
   "Operate on conda environment defined by ENV-FILE, a YAML file.
@@ -746,6 +756,12 @@ or reports an error otherwise."
                    (conda--get-executable-path) nil "env" (cdr params)))))
     (when term-buffer
       (message "%s Conda environment <%s>" (car params) env-name)
+      (let* ((proc (get-buffer-process term-buffer))
+             (current-sentinel (process-sentinel proc)))
+        (set-process-sentinel proc
+         (conda--env-process-exit-message
+          (downcase (car params)) env-name
+          current-sentinel)))
       (with-current-buffer term-buffer
         (unless (term-check-proc term-buffer)
           (term-mode)