expand-snippet: indent according to the line where snippet is expanded

Author: kiennq

lsp-mode.el

@@ -72,6 +72,7 @@
 (defvar c-basic-offset)
 (defvar yas-inhibit-overlay-modification-protection)
 (defvar yas-indent-line)
+(defvar yas-also-auto-indent-first-line)
 (defvar dap-auto-configure-mode)
 
 (defconst lsp--message-type-face
@@ -4208,6 +4209,35 @@ it has to calculate identation based on SRC block position."
   (unless (derived-mode-p 'org-mode)
     'auto))
 
+
+(defun lsp--to-yasnippet-snippet (snippet)
+  "Convert LSP SNIPPET to yasnippet snippet."
+  ;; LSP snippet doesn't escape "{", but yasnippet requires escaping it.
+  (replace-regexp-in-string (rx (or bos (not (any "$" "\\"))) (group "{"))
+                            (rx "\\" (backref 1))
+                            snippet
+                            nil nil 1))
+
+(defun lsp--expand-snippet (snippet &optional start end expand-env)
+  "Wrapper of `yas-expand-snippet' with all of it arguments.
+The snippet will be convert to LSP style and indent according to
+LSP server result."
+  (let* ((offset (save-excursion
+                   (goto-char start)
+                   (back-to-indentation)
+                   (let ((inhibit-field-text-motion t))
+                     (buffer-substring-no-properties
+                      (line-beginning-position)
+                      (point)))))
+         (yas-indent-line 'auto)
+         (yas-also-auto-indent-first-line nil)
+         (indent-line-function (lambda () (save-excursion
+                                            (forward-line 0)
+                                            (insert offset)))))
+    (yas-expand-snippet
+     (lsp--to-yasnippet-snippet snippet)
+     start end expand-env)))
+
 (defun lsp--apply-text-edits (edits)
   "Apply the edits described in the TextEdit[] object."
   (unless (seq-empty-p edits)
@@ -4238,9 +4268,7 @@ it has to calculate identation based on SRC block position."
                            (-when-let ((&SnippetTextEdit :range (&RangeToPoint :start)
                                                          :insert-text-format? :new-text) edit)
                              (when (eq insert-text-format? lsp/insert-text-format-snippet)
-                               (let ((yas-indent-line (lsp--indent-snippets?)))
-                                 (yas-expand-snippet (lsp--to-yasnippet-snippet new-text)
-                                                     start (+ start (length new-text))))))))))
+                               (lsp--expand-snippet new-text start (+ start (length new-text)))))))))
           (when (fboundp 'undo-amalgamate-change-group)
             (with-no-warnings (undo-amalgamate-change-group change-group)))
           (progress-reporter-done reporter))))))
@@ -5011,12 +5039,10 @@ Others: TRIGGER-CHARS"
           (delete-region start-point (point))
           (insert (or insert-text? label))))
 
-        (when (eq insert-text-format? 2)
-          (let ((yas-indent-line (lsp--indent-snippets?)))
-            (yas-expand-snippet
-             (lsp--to-yasnippet-snippet (buffer-substring start-point (point)))
-             start-point
-             (point))))
+        (when (equal insert-text-format? lsp/insert-text-format-snippet)
+          (lsp--expand-snippet (buffer-substring start-point (point))
+                               start-point
+                               (point)))
 
         (when (and lsp-completion-enable-additional-text-edit additional-text-edits?)
           (lsp--apply-text-edits additional-text-edits?))
@@ -5031,14 +5057,6 @@ Others: TRIGGER-CHARS"
           (setq this-command 'self-insert-command)))
     (lsp--capf-clear-cache)))
 
-(defun lsp--to-yasnippet-snippet (text)
-  "Convert LSP snippet TEXT to yasnippet snippet."
-  ;; LSP snippet doesn't escape "{", but yasnippet requires escaping it.
-  (replace-regexp-in-string (rx (or bos (not (any "$" "\\"))) (group "{"))
-                            (rx "\\" (backref 1))
-                            text
-                            nil nil 1))
-
 (defun lsp--regex-fuzzy (str)
   "Build a regex sequence from STR. Insert .* between each char."
   (apply #'concat