feat(comments): fetch an issue's full comment thread

pearl-fetch-all-comments pages the whole comment connection for the issue at point and replaces its Comments subtree with the complete set. It's bound to C-; L f c and in the transient. The bulk list and view fetch showed only the newest pearl-list-comments-shown comments with an N/M+ overflow marker, so anything past the cap couldn't surface in the buffer.

The replacement is surgical: pearl--replace-comments-subtree swaps only the Comments subtree, so the issue title, drawer, and description body keep any unsaved edits, and the new heading carries an exact N/N count. It refuses when the issue has unpushed comment edits (reusing the save model's dirty scanner) so the fetch can't clobber an unsent change.

2 files changed, 131 insertions, 1 deletions

diff --git a/tests/test-pearl-fetch-all-comments.el b/tests/test-pearl-fetch-all-comments.el
new file mode 100644
index 0000000..04dfe31
--- /dev/null
+++ b/tests/test-pearl-fetch-all-comments.el
@@ -0,0 +1,128 @@
+;;; test-pearl-fetch-all-comments.el --- Tests for fetching a full comment thread -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2026 Craig Jennings
+
+;; Author: Craig Jennings <c@cjennings.net>
+
+;; This program is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Tests for pearl-fetch-all-comments: the keybinding, the in-place
+;; Comments-subtree replacement with an exact N/N count, and the unpushed-edit
+;; guard that refuses to clobber a locally-edited comment.
+
+;;; Code:
+
+(require 'test-bootstrap (expand-file-name "test-bootstrap.el"))
+(require 'cl-lib)
+
+(defmacro test-pearl-fac--in-org (content &rest body)
+  "Run BODY in an org-mode temp buffer holding CONTENT."
+  (declare (indent 1))
+  `(let ((org-todo-keywords '((sequence "TODO" "IN-PROGRESS" "|" "DONE"))))
+     (with-temp-buffer
+       (insert ,content)
+       (org-mode)
+       (goto-char (point-min))
+       ,@body)))
+
+(defconst test-pearl-fac--with-comments
+  (concat
+   "* My open issues\n"
+   "** TODO SE-1: Alpha\n:PROPERTIES:\n:LINEAR-ID: i1\n:LINEAR-IDENTIFIER: SE-1\n:END:\n"
+   "The description body.\n"
+   "*** Comments 2/5+\n"
+   "**** Old Author — 2026-01-01T00:00:00.000Z\n"
+   ":PROPERTIES:\n:LINEAR-COMMENT-ID: oc1\n:LINEAR-COMMENT-AUTHOR-ID: u1\n"
+   ":LINEAR-COMMENT-SHA256: deadbeef\n:LINEAR-COMMENT-ORG-SHA256: deadbeef\n:END:\n"
+   "old comment one\n")
+  "An issue with a capped (overflowing) Comments subtree and a stale-hash comment.")
+
+(defconst test-pearl-fac--no-comments
+  (concat
+   "* My open issues\n"
+   "** TODO SE-1: Alpha\n:PROPERTIES:\n:LINEAR-ID: i1\n:LINEAR-IDENTIFIER: SE-1\n:END:\n"
+   "The description body.\n")
+  "An issue with no Comments subtree.")
+
+(defun test-pearl-fac--goto-issue ()
+  "Move point onto the issue heading."
+  (goto-char (point-min))
+  (re-search-forward "^\\*\\* TODO SE-1")
+  (beginning-of-line))
+
+;;; keybinding
+
+(ert-deftest test-pearl-fetch-all-comments-bound ()
+  "The command is bound under the fetch sub-keymap at `c'."
+  (should (eq 'pearl-fetch-all-comments (lookup-key pearl-fetch-map (kbd "c")))))
+
+;;; subtree replacement
+
+(ert-deftest test-pearl-replace-comments-subtree-replaces-and-counts ()
+  "Replacing swaps the capped thread for the full set with an exact N/N count."
+  (test-pearl-fac--in-org test-pearl-fac--with-comments
+    (test-pearl-fac--goto-issue)
+    (pearl--replace-comments-subtree
+     (list '(:id "c1" :author "Bob" :created-at "2026-02-01T00:00:00.000Z" :body "new one")
+           '(:id "c2" :author "Sue" :created-at "2026-02-02T00:00:00.000Z" :body "new two")))
+    (goto-char (point-min))
+    (should (search-forward "Comments 2/2" nil t))
+    (goto-char (point-min))
+    (should (search-forward "The description body." nil t))
+    (goto-char (point-min))
+    (should (search-forward "new one" nil t))
+    (goto-char (point-min))
+    (should-not (search-forward "old comment one" nil t))))
+
+(ert-deftest test-pearl-replace-comments-subtree-creates-when-absent ()
+  "An issue with no Comments subtree gets one inserted."
+  (test-pearl-fac--in-org test-pearl-fac--no-comments
+    (test-pearl-fac--goto-issue)
+    (pearl--replace-comments-subtree
+     (list '(:id "c1" :author "Bob" :created-at "2026-02-01T00:00:00.000Z" :body "hello")))
+    (goto-char (point-min))
+    (should (search-forward "Comments 1/1" nil t))
+    (goto-char (point-min))
+    (should (search-forward "hello" nil t))
+    (goto-char (point-min))
+    (should (search-forward "The description body." nil t))))
+
+(ert-deftest test-pearl-replace-comments-subtree-empty-clears ()
+  "An empty thread clears the Comments subtree."
+  (test-pearl-fac--in-org test-pearl-fac--with-comments
+    (test-pearl-fac--goto-issue)
+    (pearl--replace-comments-subtree nil)
+    (goto-char (point-min))
+    (should-not (search-forward "Comments" nil t))
+    (goto-char (point-min))
+    (should (search-forward "The description body." nil t))))
+
+;;; unpushed-edit guard
+
+(ert-deftest test-pearl-unpushed-comment-edits-p-detects-dirty ()
+  "A comment whose body no longer matches its stored hash is an unpushed edit."
+  (test-pearl-fac--in-org test-pearl-fac--with-comments
+    (test-pearl-fac--goto-issue)
+    (should (pearl--unpushed-comment-edits-p))))
+
+(ert-deftest test-pearl-unpushed-comment-edits-p-clean-when-no-comments ()
+  "An issue with no comments has no unpushed comment edits."
+  (test-pearl-fac--in-org test-pearl-fac--no-comments
+    (test-pearl-fac--goto-issue)
+    (should-not (pearl--unpushed-comment-edits-p))))
+
+(provide 'test-pearl-fetch-all-comments)
+;;; test-pearl-fetch-all-comments.el ends here
diff --git a/tests/test-pearl-menu.el b/tests/test-pearl-menu.el
index 8d23023..825d6bc 100644
--- a/tests/test-pearl-menu.el
+++ b/tests/test-pearl-menu.el
@@ -76,7 +76,9 @@ menu entry that still points at it fails here."
                         pearl-switch-account
                         pearl-copy-issue-url
                         ;; set-default-view: the new Views-group entry
-                        pearl-set-default-view))
+                        pearl-set-default-view
+                        ;; fetch the full comment thread for the issue at point
+                        pearl-fetch-all-comments))
       (should (memq expected cmds)))))
 
 (provide 'test-pearl-menu)