Suggestions: Add support for insertReplaceSupport

[kcbanner]

Since 3.16, LSP supports the capability insertReplaceSupport. This allows textEdit to be an InsertReplaceEdit: https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#insertReplaceEdit

As an example of where this is useful:

eglot_complete_no_overwrite_1.mp4

In this case, the token is not replaced correctly. I believe insertReplaceEdit would allow this replacement to occur.

[joaotavora]

I don't understand what you are doing in the video. Is this Emacs or Vim? Can you explain very clearly in text form what is it that doesn't happen correctly today, and what you would like to see happen tomorrow?

…

On Mon, Oct 14, 2024, 19:35 Casey Banner ***@***.***> wrote: Since 3.16, LSP supports the capability insertReplaceSupport. This allows textEdit to be an InsertReplaceEdit: https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#insertReplaceEdit As an example of where this is useful: https://github.com/user-attachments/assets/2e3c2009-8fad-449d-abee-dfd3b8e04acb In this case, the token is not replaced correctly. I believe insertReplaceEdit would allow this replacement to occur. — Reply to this email directly, view it on GitHub <#1456>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAC6PQYH5TZIZMZ5TU532BDZ3QFGZAVCNFSM6AAAAABP5RTAJGVHI2DSMVQWIX3LMV43ERDJONRXK43TNFXW4OZXGMYTQMJSGI> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[kcbanner]

In the video I'm using emacs with evil-mode.

Here is a better example and minimal reproduction of the issue:

Start with the following file:

const Foo = struct {
    correct_name: u32,
};

fn example(foo: Foo) u32 {
    return foo.correct_name;
}

1. Place the cursor on 6:22 (the _ in correct_name)
2. Backspace once to delete the t
3. Receive the following LSP message: <-- textDocument/completion[20] {"jsonrpc":"2.0","id":20,"result":{"isIncomplete":false,"items":[{"label":"correct_name","kind":5,"detail":"u32","documentation":{"kind":"plaintext","value":""},"sortText":"2_correct_name","textEdit":{"range":{"start":{"line":5,"character":15},"end":{"line":5,"character":21}},"newText":"correct_name"}}]}}
4. Accept the completion
5. The buffer now contains return foo.correct_name_name; on line 6

Expected behaviour:

On step 5, the buffer should contain: return foo.correct_name; on line 6.

I believe that if InsertReplaceEdit support was implemented, that textEdit in step 3 would instead be:

"textEdit": {
    "replace": {
        "start": {
            "line": 5,
            "character": 15
        },
        "end": {
            "line": 5,
            "character": 25
        }
    },
    "newText": "correct_name"
}

Note that the range field is now replace (as it is now an InsertReplaceEdit) and the range covers the entire token (correc_name). I'm not that familiar with completion internals, but I believe this range information could be passed along to the completion system to replace the entire range?

[kcbanner]

I have a patch that seems to work for me:

0001-lisp-progmodes-eglot.el-add-support-for-insertReplac.patch

From 50620e96d763bd21854a95c580b572687eebc319 Mon Sep 17 00:00:00 2001
From: kcbanner <[email protected]>
Date: Thu, 17 Oct 2024 00:43:32 -0400
Subject: [PATCH] * lisp/progmodes/eglot.el: add support for insertReplaceEdit

---
 lisp/progmodes/eglot.el | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/lisp/progmodes/eglot.el b/lisp/progmodes/eglot.el
index 0a14146a245..95eee51faa5 100644
--- a/lisp/progmodes/eglot.el
+++ b/lisp/progmodes/eglot.el
@@ -647,6 +647,7 @@ eglot--uri-path-allowed-chars
                       (:detail :deprecated :children))
       (TextDocumentEdit (:textDocument :edits) ())
       (TextEdit (:range :newText))
+      (InsertReplaceEdit (:newText :insert :replace))
       (VersionedTextDocumentIdentifier (:uri :version) ())
       (WorkDoneProgress (:kind) (:title :message :percentage :cancellable))
       (WorkspaceEdit () (:changes :documentChanges))
@@ -959,7 +960,8 @@ eglot-client-capabilities
                                                        ["documentation"
                                                         "details"
                                                         "additionalTextEdits"])
-                                      :tagSupport (:valueSet [1]))
+                                      :tagSupport (:valueSet [1])
+                                      :insertReplaceSupport t)
                                     :contextSupport t)
              :hover              (list :dynamicRegistration :json-false
                                        :contentFormat (eglot--accepted-formats))
@@ -3368,12 +3370,19 @@ eglot-completion-at-point
                         ;; state, _not_ the current "foo.bar".
                         (delete-region orig-pos (point))
                         (insert (substring bounds-string (- orig-pos (car bounds))))
-                        (eglot--dbind ((TextEdit) range newText) textEdit
-                          (pcase-let ((`(,beg . ,end)
+                        (eglot--dcase textEdit
+                          (((TextEdit) range newText)
+                           (pcase-let ((`(,beg . ,end)
                                        (eglot-range-region range)))
                             (delete-region beg end)
                             (goto-char beg)
-                            (funcall (or snippet-fn #'insert) newText))))
+                            (funcall (or snippet-fn #'insert) newText)))
+                          (((InsertReplaceEdit) newText insert replace)
+                           (pcase-let ((`(,beg . ,end)
+                                        (eglot-range-region replace)))
+                             (delete-region beg end)
+                             (goto-char beg)
+                             (funcall (or snippet-fn #'insert) newText)))))
                        (snippet-fn
                         ;; A snippet should be inserted, but using plain
                         ;; `insertText'.  This requires us to delete the
@@ -3602,8 +3611,12 @@ eglot--apply-text-edits
                           (replace-buffer-contents temp)))
                       (when reporter
                         (eglot--reporter-update reporter (cl-incf done))))))))
-            (mapcar (eglot--lambda ((TextEdit) range newText)
-                      (cons newText (eglot-range-region range 'markers)))
+            (mapcar (lambda (text-edit-or-insert-replace-edit)
+                      (eglot--dcase text-edit-or-insert-replace-edit
+                        (((TextEdit) range newText)
+                         (cons newText (eglot-range-region range 'markers)))
+                        (((InsertReplaceEdit) newText insert replace)
+                         (cons newText (eglot-range-region replace 'markers)))))
                     (reverse edits)))
       (undo-amalgamate-change-group change-group)
       (when reporter
-- 
2.46.0.windows.1

eglot_patch_1.mp4

This is the first real elisp that I've written so I'm not sure if this is the correct way, but it seems to work for me.