master 9fb8590: flymake-diagnostic-beg/end doc string and error reporting improvement

[Lars Ingebrigtsen]

branch: master
commit 9fb859010fa624f4b63ad4a1a8ba22a0f64f16f2
Author: Lars Ingebrigtsen <larsi@gnus.org>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    flymake-diagnostic-beg/end doc string and error reporting improvement
    
    * lisp/progmodes/flymake.el (flymake-diagnostic-beg):
    (flymake-diagnostic-end): Improve doc string and error reporting
    (bug#39971).
---
 lisp/progmodes/flymake.el | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/lisp/progmodes/flymake.el b/lisp/progmodes/flymake.el
index 460af71..5d96c62 100644
--- a/lisp/progmodes/flymake.el
+++ b/lisp/progmodes/flymake.el
@@ -352,12 +352,20 @@ diagnostics at BEG."
 (flymake--diag-accessor flymake-diagnostic-data flymake--diag-data backend)
 
 (defun flymake-diagnostic-beg (diag)
-  "Get Flymake diagnostic DIAG's start position."
-  (overlay-start (flymake--diag-overlay diag)))
+  "Get Flymake diagnostic DIAG's start position.
+This position only be queried after DIAG has been reported to Flymake."
+  (let ((overlay (flymake--diag-overlay diag)))
+    (unless overlay
+      (error "DIAG %s not reported to Flymake yet" diag))
+    (overlay-start overlay)))
 
 (defun flymake-diagnostic-end (diag)
-  "Get Flymake diagnostic DIAG's end position."
-  (overlay-end (flymake--diag-overlay diag)))
+  "Get Flymake diagnostic DIAG's end position.
+This position only be queried after DIAG has been reported to Flymake."
+  (let ((overlay (flymake--diag-overlay diag)))
+    (unless overlay
+      (error "DIAG %s not reported to Flymake yet" diag))
+    (overlay-end overlay)))
 
 (cl-defun flymake--overlays (&key beg end filter compare key)
   "Get flymake-related overlays.