From e233513d28210a7aacc750a5e70fc8352b4bf12d Mon Sep 17 00:00:00 2001
From: Stefan Monnier <monnier@iro.umontreal.ca>
Date: Mon, 24 Nov 2025 10:26:21 -0500
Subject: [PATCH] editorconfig-core-handle.el: Fix silent misparse
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See https://github.com/editorconfig/editorconfig-emacs/issues/380

* lisp/editorconfig-core-handle.el (editorconfig-core-handle--parse-file):
Fix regexp to not inadvertently match LF.  Remove an O(N²) complexity.
Use `line-number-at-pos`.

* lisp/editorconfig.el (editorconfig--get-coding-system): Don't let
errors propagate.
---
 lisp/editorconfig-core-handle.el | 13 ++++---------
 lisp/editorconfig.el             | 26 +++++++++++++++-----------
 2 files changed, 19 insertions(+), 20 deletions(-)

diff --git a/lisp/editorconfig-core-handle.el b/lisp/editorconfig-core-handle.el
index 5dd8c73d4e2..892ad61b6d3 100644
--- a/lisp/editorconfig-core-handle.el
+++ b/lisp/editorconfig-core-handle.el
@@ -166,10 +166,7 @@ If CONF is not found return nil."
             ;; nil when pattern not appeared yet, "" when pattern is empty ("[]")
             (pattern nil)
             ;; Alist of properties for current PATTERN
-            (props ())
-
-            ;; Current line num
-            (current-line-number 1))
+            (props ()))
         (while (not (eobp))
           (skip-chars-forward " \t\f")
           (cond
@@ -187,7 +184,7 @@ If CONF is not found return nil."
               (setq props nil)
               (setq pattern newpattern)))
 
-           ((looking-at "\\([^=: \t][^=:]*\\)[ \t]*[=:][ \t]*\\(.*?\\)[ \t]*$")
+           ((looking-at "\\([^=: \n\t][^=:\n]*\\)[ \t]*[=:][ \t]*\\(.*?\\)[ \t]*$")
             (let ((key (downcase (string-trim (match-string 1))))
                   (value (match-string 2)))
               (if pattern
@@ -197,12 +194,10 @@ If CONF is not found return nil."
                       top-props))))
 
            (t (error "Error while reading config file: %s:%d:\n    %s\n"
-                     conf current-line-number
+                     conf (line-number-at-pos)
                      (buffer-substring-no-properties (line-beginning-position)
                                                      (line-end-position)))))
-          (setq current-line-number (1+ current-line-number))
-          (goto-char (point-min))
-          (forward-line (1- current-line-number)))
+          (forward-line 1))
         (when pattern
           (push (make-editorconfig-core-handle-section
                  :name pattern
diff --git a/lisp/editorconfig.el b/lisp/editorconfig.el
index 04c7314369d..42ff3038b92 100644
--- a/lisp/editorconfig.el
+++ b/lisp/editorconfig.el
@@ -658,17 +658,21 @@ F is that function, and FILENAME and ARGS are arguments passed to F."
   "Return the coding system to use according to EditorConfig.
 Meant to be used on `auto-coding-functions'."
   (defvar auto-coding-file-name) ;; Emacs≥30
-  (when (and (stringp auto-coding-file-name)
-             (file-name-absolute-p auto-coding-file-name)
-	     ;; Don't recurse infinitely.
-	     (not (member auto-coding-file-name
-	                  editorconfig--getting-coding-system)))
-    (let* ((editorconfig--getting-coding-system
-            (cons auto-coding-file-name editorconfig--getting-coding-system))
-           (props (editorconfig-call-get-properties-function
-                   auto-coding-file-name)))
-      (editorconfig-merge-coding-systems (gethash 'end_of_line props)
-                                         (gethash 'charset props)))))
+  ;; Not only we don't want that an error in the `.editorconfig' file
+  ;; prevents opening a file but we don't want an error to be dropped on
+  ;; the floor by some `ignore-errors' higher up.
+  (with-demoted-errors "EditorConfig: %S"
+    (when (and (stringp auto-coding-file-name)
+               (file-name-absolute-p auto-coding-file-name)
+	       ;; Don't recurse infinitely.
+	       (not (member auto-coding-file-name
+	                    editorconfig--getting-coding-system)))
+      (let* ((editorconfig--getting-coding-system
+              (cons auto-coding-file-name editorconfig--getting-coding-system))
+             (props (editorconfig-call-get-properties-function
+                     auto-coding-file-name)))
+        (editorconfig-merge-coding-systems (gethash 'end_of_line props)
+                                           (gethash 'charset props))))))
 
 (defun editorconfig--get-dir-local-variables ()
   "Return the directory local variables specified via EditorConfig.