From: João Távora <joaotavora@gmail.com>
Date: Fri, 29 Mar 2019 12:27:11 +0000 (+0000)
Subject: Protect Flymake from being corrupted by backends
X-Git-Tag: emacs-27.0.90~2125
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=2a2a1bdb8f0f149aaf736a61685feec9380be1b1;p=emacs.git

Protect Flymake from being corrupted by backends

A backend building a diagnostic with a nil :type would cause Flymake
to create a diagnostic without an overlay, confusing Flymake's
accounting of overlays and diagnostics

* lisp/progmodes/flymake.el (flymake--highlight-line): Return
non-nil unconditionally.
---

diff --git a/lisp/progmodes/flymake.el b/lisp/progmodes/flymake.el
index 83b5ee33aa0..6f3d2d59b5c 100644
--- a/lisp/progmodes/flymake.el
+++ b/lisp/progmodes/flymake.el
@@ -604,10 +604,11 @@ associated `flymake-category' return DEFAULT."
 
 (defun flymake--highlight-line (diagnostic)
   "Highlight buffer with info in DIGNOSTIC."
-  (when-let* ((type (flymake--diag-type diagnostic))
-              (ov (make-overlay
-                   (flymake--diag-beg diagnostic)
-                   (flymake--diag-end diagnostic))))
+  (let ((type (or (flymake--diag-type diagnostic)
+                  :error))
+        (ov (make-overlay
+             (flymake--diag-beg diagnostic)
+             (flymake--diag-end diagnostic))))
     ;; First set `category' in the overlay
     ;;
     (overlay-put ov 'category