From eec711c9df63415aaeaaa3382eb2a89b1e59e53d Mon Sep 17 00:00:00 2001
From: "F. Jason Park" <jp@neverwas.me>
Date: Tue, 27 Aug 2024 23:05:35 -0700
Subject: [PATCH 5/6] [5.6.1] Fix overlooked case in
 erc--get-inserted-msg-beg-at

* lisp/erc/erc.el (erc--get-inserted-msg-beg-at): Account for the start
of a props header being `bobp' when searching backwards.
(erc--get-inserted-msg-prop): Add optional `point' parameter.
* test/lisp/erc/erc-goodies-tests.el
(erc--get-inserted-msg-beg/truncated/readonly): New test.
* test/lisp/erc/erc-tests.el (erc--get-inserted-msg-beg/truncated): New
test.
* test/lisp/erc/resources/erc-tests-common.el
(erc-tests-common-assert-get-inserted-msg/truncated): New test helper.
(Bug#72736)
---
 lisp/erc/erc.el                             | 16 ++++++++++------
 test/lisp/erc/erc-goodies-tests.el          |  5 +++++
 test/lisp/erc/erc-tests.el                  |  4 ++++
 test/lisp/erc/resources/erc-tests-common.el |  7 +++++++
 4 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/lisp/erc/erc.el b/lisp/erc/erc.el
index 52ec4d23dd7..7d006db69a6 100644
--- a/lisp/erc/erc.el
+++ b/lisp/erc/erc.el
@@ -3323,10 +3323,14 @@ erc--get-inserted-msg-beg-at
   (macroexp-let2* nil ((point point)
                        (at-start-p at-start-p))
     `(or (and ,at-start-p ,point)
-         (and-let* ((p (previous-single-property-change ,point 'erc--msg)))
-           (if (and (= p (1- ,point)) (get-text-property p 'erc--msg))
-               p
-             (1- p))))))
+         (let ((p (previous-single-property-change ,point 'erc--msg)))
+           (cond
+            ((and p (= p (1- ,point)) (get-text-property p 'erc--msg)) p)
+            (p (1- p))
+            ((and (null p)
+                  (> ,point (point-min))
+                  (get-text-property (1- point) 'erc--msg))
+             (1- point)))))))
 
 (defmacro erc--get-inserted-msg-end-at (point at-start-p)
   (macroexp-let2 nil point point
@@ -3355,9 +3359,9 @@ erc--get-inserted-msg-bounds
     (and-let* ((b (erc--get-inserted-msg-beg-at point at-start-p)))
       (cons b (erc--get-inserted-msg-end-at point at-start-p)))))
 
-(defun erc--get-inserted-msg-prop (prop)
+(defun erc--get-inserted-msg-prop (prop &optional point)
   "Return the value of text property PROP for some message at point."
-  (and-let* ((stack-pos (erc--get-inserted-msg-beg (point))))
+  (and-let* ((stack-pos (erc--get-inserted-msg-beg (or point (point)))))
     (get-text-property stack-pos prop)))
 
 ;; FIXME improve this nascent "message splicing" facility to include a
diff --git a/test/lisp/erc/erc-goodies-tests.el b/test/lisp/erc/erc-goodies-tests.el
index 038434b3880..1d74025c5ce 100644
--- a/test/lisp/erc/erc-goodies-tests.el
+++ b/test/lisp/erc/erc-goodies-tests.el
@@ -597,6 +597,11 @@ erc--get-inserted-msg-beg/readonly
    #'erc-tests-common-assert-get-inserted-msg/basic
    (lambda (arg) (should (= 3 (erc--get-inserted-msg-beg arg))))))
 
+(ert-deftest erc--get-inserted-msg-beg/truncated/readonly ()
+  (erc-tests-common-assert-get-inserted-msg-readonly-with
+   #'erc-tests-common-assert-get-inserted-msg/truncated
+   (lambda (arg) (should (= 1 (erc--get-inserted-msg-beg arg))))))
+
 (ert-deftest erc--get-inserted-msg-end/readonly ()
   (erc-tests-common-assert-get-inserted-msg-readonly-with
    #'erc-tests-common-assert-get-inserted-msg/basic
diff --git a/test/lisp/erc/erc-tests.el b/test/lisp/erc/erc-tests.el
index 72ea11aeba1..eddb3a5b2c8 100644
--- a/test/lisp/erc/erc-tests.el
+++ b/test/lisp/erc/erc-tests.el
@@ -1934,6 +1934,10 @@ erc--get-inserted-msg-beg/basic
   (erc-tests-common-assert-get-inserted-msg/basic
    (lambda (arg) (should (= 3 (erc--get-inserted-msg-beg arg))))))
 
+(ert-deftest erc--get-inserted-msg-beg/truncated ()
+  (erc-tests-common-assert-get-inserted-msg/truncated
+   (lambda (arg) (should (= 1 (erc--get-inserted-msg-beg arg))))))
+
 (ert-deftest erc--get-inserted-msg-end/basic ()
   (erc-tests-common-assert-get-inserted-msg/basic
    (lambda (arg) (should (= 11 (erc--get-inserted-msg-end arg))))))
diff --git a/test/lisp/erc/resources/erc-tests-common.el b/test/lisp/erc/resources/erc-tests-common.el
index b5bb1fb09c3..1cd54a1f715 100644
--- a/test/lisp/erc/resources/erc-tests-common.el
+++ b/test/lisp/erc/resources/erc-tests-common.el
@@ -184,6 +184,13 @@ erc-tests-common-assert-get-inserted-msg/basic
   (should (looking-back "<bob> hi"))
   (erc-tests-common-assert-get-inserted-msg 3 11 test-fn))
 
+(defun erc-tests-common-assert-get-inserted-msg/truncated (test-fn)
+  (erc-tests-common-get-inserted-msg-setup)
+  (with-silent-modifications (delete-region 1 3))
+  (goto-char 9)
+  (should (looking-back "<bob> hi"))
+  (erc-tests-common-assert-get-inserted-msg 1 9 test-fn))
+
 ;; This is a "mixin" and requires a base assertion function, like
 ;; `erc-tests-common-assert-get-inserted-msg/basic', to work.
 (defun erc-tests-common-assert-get-inserted-msg-readonly-with
-- 
2.46.0