Merge pull request #297 from agzam/restore-prompt-on-rollback

Restore rolled-back message into the prompt field

Author: ericdallo

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- Restore the rolled-back user message into the prompt field. `Rollback chat to before this message` (when messages are included) used to discard the clicked message's text together with the rest of the turn; the text now lands in the prompt unsent, ready to edit and resend, and any draft already typed in the prompt is kept below it, separated by a blank line.
 - Fall back to the buffer's `xref` backend (eglot, etags with a loaded tags table, any custom backend) for `editor/getDefinition`/`editor/getReferences` when lsp-mode cannot serve the file, instead of answering no-server. `includeDeclaration: false` is honored by filtering definition locations out of the references, since LSP-backed xref backends always include the declaration. (editor-code-assistant/eca#351)
 
 - Support `editor/getDefinition` and `editor/getReferences` server requests via lsp-mode, letting the LLM navigate to a symbol definition/references using the editor's LSP. When no server is attached yet for a file of a known lsp project, lsp is started in background and `starting` is answered so the eca server retries. `starting` is also answered while an attached workspace is still initializing, since lsp-mode would reject the request with a misleading "does not support method" capability error before the initialize handshake completes. Synchronous lsp-mode errors are answered as `error` responses, and any server-request handler error now answers an error response instead of escaping into the process filter ("error in process filter" in Messages) and leaving the request pending until the server times it out (30s). Requires eca server with editor navigation support (editor-code-assistant/eca#351).

eca-chat.el

@@ -708,6 +708,12 @@ Set by `eca-chat--kill-buffer-query' and consumed by
 Set when the welcome message and resume link are inserted in
 `eca-chat-mode'; cleared by `eca-chat--clear'.  Used to decide
 whether the first user prompt should erase the banner first.")
+
+(defvar-local eca-chat--prompt-after-clear nil
+  "Prompt text to restore after the next server-initiated clear.
+Set by `eca-chat--rollback' so the rolled-back user message and
+any prompt draft survive the `chat/cleared' redraw; consumed
+once by `eca-chat-cleared'.")
 (defvar-local eca-chat--id nil)
 (defvar-local eca-chat--title nil)
 (defvar-local eca-chat--custom-title nil)
@@ -1646,8 +1652,23 @@ stopping while one is pending: cancel it, then notify the server."
                     :params (list :chatId eca-chat--id))
     (eca-chat--set-chat-loading session 'stopping)))
 
-(defun eca-chat--rollback (session content-id)
-  "Rollback chat messages for SESSION to before CONTENT-ID."
+(defun eca-chat--rollback-prompt-text (text)
+  "Join rolled-back TEXT with the current prompt draft.
+The draft goes after TEXT, separated by a blank line, so edits
+typed before the rollback are kept.  Return nil when both are
+empty."
+  (let ((restored (string-trim (or text "")))
+        (draft (or (eca-chat--prompt-content) "")))
+    (cond
+     ((string-empty-p draft) (unless (string-empty-p restored) restored))
+     ((string-empty-p restored) draft)
+     (t (concat restored "\n\n" draft)))))
+
+(defun eca-chat--rollback (session content-id &optional text)
+  "Rollback chat messages for SESSION to before CONTENT-ID.
+TEXT is the rolled-back user message text; when the rollback
+removes messages, it is restored into the prompt field with any
+current draft appended, after the server clears the chat."
   (unless eca-chat--chat-loading
     (let ((rollback-messages-and-tools-str "1. Rollback messages and changes done by tool calls")
           (rollback-messages-str "2. Rollback only messages")
@@ -1666,11 +1687,18 @@ stopping while one is pending: cancel it, then notify the server."
                         ((string= rollback-type rollback-messages-str) ["messages"])
                         ((string= rollback-type rollback-tools-str) ["tools"])
                         ((string= rollback-type rollback-messages-and-tools-str) ["messages" "tools"]))))
-          (eca-api-request-sync session
-                                :method "chat/rollback"
-                                :params (list :chatId eca-chat--id
-                                              :contentId content-id
-                                              :include include)))))))
+          (when (member "messages" (append include nil))
+            (setq-local eca-chat--prompt-after-clear
+                        (eca-chat--rollback-prompt-text text)))
+          (unwind-protect
+              (eca-api-request-sync session
+                                    :method "chat/rollback"
+                                    :params (list :chatId eca-chat--id
+                                                  :contentId content-id
+                                                  :include include))
+            ;; `eca-chat-cleared' consumes the stash during the sync
+            ;; wait; this reset only drops a leftover on request failure.
+            (setq-local eca-chat--prompt-after-clear nil)))))))
 
 (defun eca-chat--remove-flag (session content-id)
   "Remove a flag identified by CONTENT-ID from the chat via SESSION."
@@ -4003,7 +4031,7 @@ Must be called with `eca-chat--with-current-buffer' or equivalent."
                  (eca-buttonize
                   eca-chat-mode-map
                   (propertize "Rollback chat to before this message" 'font-lock-face 'eca-chat-rollback-face)
-                  (lambda () (eca-chat--rollback session content-id))))
+                  (lambda () (eca-chat--rollback session content-id (string-trim text)))))
                 (when-let* ((ov (eca-chat--get-expandable-content content-id)))
                   (overlay-put ov 'eca-chat--user-message-id content-id)
                   (overlay-put ov 'eca-chat--timestamp (float-time)))
@@ -4596,7 +4624,9 @@ Shown at the top of the buffer only when an older page is available
     (when (buffer-live-p chat-buffer)
       (eca-chat--with-current-buffer chat-buffer
         (when messages?
-          (eca-chat--clear))))))
+          (let ((new-prompt eca-chat--prompt-after-clear))
+            (setq-local eca-chat--prompt-after-clear nil)
+            (eca-chat--clear new-prompt)))))))
 
 (defun eca-chat--legacy-open-config-p (chat-config)
   "Return non-nil for a legacy unscoped chat/open restore update."

test/eca-chat-test.el

@@ -1788,4 +1788,120 @@ CHOOSE receives the candidate list the command offers."
     (expect (eca-chat--mode-line-module eca-chat-test--ws-session :remove-workspace-button)
             :to-be nil)))
 
+(describe "eca-chat--rollback-prompt-text"
+
+  (it "returns the rolled-back text when there is no draft"
+    (with-temp-buffer
+      (expect (eca-chat--rollback-prompt-text "redo this") :to-equal "redo this")))
+
+  (it "returns nil when both text and draft are empty"
+    (with-temp-buffer
+      (expect (eca-chat--rollback-prompt-text nil) :to-be nil)
+      (expect (eca-chat--rollback-prompt-text "   ") :to-be nil)))
+
+  (it "appends the draft after the rolled-back text"
+    (let ((buf (eca-chat-test--make-prompt-buffer "draft edit")))
+      (unwind-protect
+          (with-current-buffer buf
+            (expect (eca-chat--rollback-prompt-text "old msg")
+                    :to-equal "old msg\n\ndraft edit"))
+        (kill-buffer buf))))
+
+  (it "keeps a lone draft when there is no rolled-back text"
+    (let ((buf (eca-chat-test--make-prompt-buffer "draft edit")))
+      (unwind-protect
+          (with-current-buffer buf
+            (expect (eca-chat--rollback-prompt-text nil) :to-equal "draft edit"))
+        (kill-buffer buf))))
+
+  (it "ignores a whitespace-only draft"
+    (let ((buf (eca-chat-test--make-prompt-buffer "   ")))
+      (unwind-protect
+          (with-current-buffer buf
+            (expect (eca-chat--rollback-prompt-text "old msg") :to-equal "old msg"))
+        (kill-buffer buf)))))
+
+(describe "eca-chat--rollback"
+
+  (it "stashes restored text plus draft for a messages rollback"
+    (let ((buf (eca-chat-test--make-prompt-buffer "draft edit"))
+          (session (make-eca--session))
+          (captured 'unset))
+      (unwind-protect
+          (with-current-buffer buf
+            (setq-local eca-chat--id "chat-1")
+            (spy-on 'completing-read
+                    :and-return-value "2. Rollback only messages")
+            ;; Capture the stash as the server request sees it: the
+            ;; `chat/cleared' notification consumes it during the sync wait.
+            (spy-on 'eca-api-request-sync :and-call-fake
+                    (lambda (&rest _)
+                      (setq captured eca-chat--prompt-after-clear)))
+            (eca-chat--rollback session "content-1" "old msg")
+            (expect captured :to-equal "old msg\n\ndraft edit")
+            (expect 'eca-api-request-sync :to-have-been-called)
+            ;; The unwind reset drops any unconsumed leftover.
+            (expect eca-chat--prompt-after-clear :to-be nil))
+        (kill-buffer buf))))
+
+  (it "does not stash for a tools-only rollback"
+    (let ((buf (eca-chat-test--make-prompt-buffer "draft edit"))
+          (session (make-eca--session))
+          (captured 'unset))
+      (unwind-protect
+          (with-current-buffer buf
+            (setq-local eca-chat--id "chat-1")
+            (spy-on 'completing-read
+                    :and-return-value "3. Rollback only changes done by tool calls")
+            (spy-on 'eca-api-request-sync :and-call-fake
+                    (lambda (&rest _)
+                      (setq captured eca-chat--prompt-after-clear)))
+            (eca-chat--rollback session "content-1" "old msg")
+            (expect captured :to-be nil)
+            (expect 'eca-api-request-sync :to-have-been-called))
+        (kill-buffer buf)))))
+
+(describe "eca-chat-cleared"
+
+  (it "restores the stashed prompt into the rebuilt prompt field"
+    (let ((buf (eca-chat-test--make-prompt-buffer "draft edit"))
+          (session (make-eca--session)))
+      (unwind-protect
+          (with-current-buffer buf
+            (setq-local eca-chat--id "chat-1")
+            (setq-local eca-chat--prompt-after-clear "old msg\n\ndraft edit")
+            (spy-on 'eca-chat--get-chat-buffer :and-return-value buf)
+            (spy-on 'eca-chat--refresh-context)
+            (eca-chat-cleared session (list :chatId "chat-1" :messages t))
+            (expect (eca-chat-test--prompt-text buf)
+                    :to-equal "old msg\n\ndraft edit")
+            (expect eca-chat--prompt-after-clear :to-be nil))
+        (kill-buffer buf))))
+
+  (it "leaves the prompt empty when nothing is stashed"
+    (let ((buf (eca-chat-test--make-prompt-buffer "leftover")))
+      (unwind-protect
+          (with-current-buffer buf
+            (setq-local eca-chat--id "chat-1")
+            (spy-on 'eca-chat--get-chat-buffer :and-return-value buf)
+            (spy-on 'eca-chat--refresh-context)
+            (eca-chat-cleared (make-eca--session)
+                              (list :chatId "chat-1" :messages t))
+            (expect (eca-chat-test--prompt-text buf) :to-equal ""))
+        (kill-buffer buf))))
+
+  (it "does not clear nor consume the stash when messages is nil"
+    (let ((buf (eca-chat-test--make-prompt-buffer "draft edit")))
+      (unwind-protect
+          (with-current-buffer buf
+            (setq-local eca-chat--id "chat-1")
+            (setq-local eca-chat--prompt-after-clear "old msg")
+            (spy-on 'eca-chat--get-chat-buffer :and-return-value buf)
+            (spy-on 'eca-chat--clear)
+            (eca-chat-cleared (make-eca--session)
+                              (list :chatId "chat-1" :messages nil))
+            (expect 'eca-chat--clear :not :to-have-been-called)
+            (expect eca-chat--prompt-after-clear :to-equal "old msg"))
+        (kill-buffer buf)))))
+
 ;;; eca-chat-test.el ends here