fix(custom-comments): correct comment-reformat and inline-border

cj/comment-reformat printed "No region was selected" on every call, even successful ones, because the message sat outside the if. Its fill-column shrink used a raw setq and restore, so an error mid-join left fill-column permanently at -3. It now signals a user-error when there's no region and dynamically binds fill-column, which restores itself.

cj/--comment-inline-border sized the right decoration from text-length parity, leaving even-length and empty text two columns short and misaligning stacked dividers. It now fills the exact remaining width. Both fixes ship with tests, and the inline-border test asserts exact width across parities.

3 files changed, 34 insertions, 25 deletions

diff --git a/modules/custom-comments.el b/modules/custom-comments.el
index a2604a55..73d29b0c 100644
--- a/modules/custom-comments.el
+++ b/modules/custom-comments.el
@@ -35,19 +35,19 @@
 ;; ------------------------------ Comment Reformat -----------------------------
 
 (defun cj/comment-reformat ()
-  "Reformat commented text into a single paragraph."
+  "Reformat the commented text in the active region into a single paragraph.
+Signal a `user-error' when no region is active."
   (interactive)
-  (if mark-active
-      (let ((beg (region-beginning))
-            (end (copy-marker (region-end)))
-            (orig-fill-column fill-column))
-        (uncomment-region beg end)
-        (setq fill-column (- fill-column 3))
-        (cj/join-line-or-region)
-        (comment-region beg end)
-        (setq fill-column orig-fill-column )))
-  ;; if no region
-  (message "No region was selected. Select the comment lines to reformat."))
+  (unless (use-region-p)
+    (user-error "No region selected: select the comment lines to reformat"))
+  (let ((beg (region-beginning))
+        (end (copy-marker (region-end)))
+        ;; Dynamically narrow the fill target for the join, then let it
+        ;; restore itself -- an error mid-join no longer strands fill-column.
+        (fill-column (- fill-column 3)))
+    (uncomment-region beg end)
+    (cj/join-line-or-region)
+    (comment-region beg end)))
 
 ;; ======================== Comment Generation Functions =======================
 
@@ -95,6 +95,14 @@ LENGTH is the total width of the line."
                                   text-length
                                   (if (> text-length 0) 2 0))  ; spaces around text
                                2))
+         ;; The right side fills the exact remaining width so the line always
+         ;; reaches LENGTH.  Keying this off text-length parity (as before) left
+         ;; even-length and empty text two columns short, misaligning stacked
+         ;; dividers of differing text lengths.
+         (right-space (- available-width
+                         text-length
+                         (if (> text-length 0) 2 0)
+                         space-on-each-side))
          (min-space 2))
     ;; Validate we have enough space
     (when (< space-on-each-side min-space)
@@ -108,10 +116,8 @@ LENGTH is the total width of the line."
     ;; Text with spaces
     (when (> text-length 0)
       (insert " " text " "))
-    ;; Right decoration (handle odd-length text)
-    (dotimes (_ (if (= (% text-length 2) 0)
-                    (- space-on-each-side 1)
-                  space-on-each-side))
+    ;; Right decoration -- fills the exact remaining width so the line reaches LENGTH.
+    (dotimes (_ right-space)
       (insert decoration-char))
     ;; Comment end
     (when (not (string-empty-p cmt-end))
diff --git a/tests/test-custom-comments-comment-inline-border.el b/tests/test-custom-comments-comment-inline-border.el
index 78e86035..305a2c7a 100644
--- a/tests/test-custom-comments-comment-inline-border.el
+++ b/tests/test-custom-comments-comment-inline-border.el
@@ -120,6 +120,16 @@ Returns the buffer string for assertions."
   (let ((result (test-inline-border-at-column 0 ";;" "" "=" "" 10)))
     (should (string-match-p ";" result))))
 
+(ert-deftest test-inline-border-elisp-fills-exact-width-all-parities ()
+  "Boundary: even, odd, and empty text all fill LENGTH exactly.
+Even-length and empty text used to come out two columns short because the
+right decoration count keyed off text-length parity instead of the remaining
+width, so stacked dividers of differing text lengths misaligned."
+  (dolist (text '("" "X" "EVEN" "ODD" "Header"))
+    (let* ((result (test-inline-border-at-column 0 ";;" "" "=" text 50))
+           (line (string-trim-right result "\n")))
+      (should (= 50 (length line))))))
+
 (ert-deftest test-inline-border-elisp-text-centering-even ()
   "Should center text properly with even length."
   (let ((result (test-inline-border-at-column 0 ";;" "" "=" "EVEN" 70)))
diff --git a/tests/test-custom-comments-comment-reformat.el b/tests/test-custom-comments-comment-reformat.el
index 83248aee..91b7dfe3 100644
--- a/tests/test-custom-comments-comment-reformat.el
+++ b/tests/test-custom-comments-comment-reformat.el
@@ -146,19 +146,12 @@ Insert CONTENT-BEFORE, select all, run cj/comment-reformat, verify EXPECTED-AFTE
     (should (string-match-p ";; Start line 1.*Start line 2" (buffer-string)))))
 
 (ert-deftest test-comment-reformat-elisp-no-region-active ()
-  "Should show message when no region selected."
+  "Should signal `user-error' when no region is selected."
   (with-temp-buffer
     (emacs-lisp-mode)
     (insert ";; Comment line")
     (deactivate-mark)
-    (let ((message-log-max nil)
-          (messages '()))
-      ;; Capture messages
-      (cl-letf (((symbol-function 'message)
-                 (lambda (format-string &rest args)
-                   (push (apply #'format format-string args) messages))))
-        (cj/comment-reformat)
-        (should (string-match-p "No region was selected" (car messages)))))))
+    (should-error (cj/comment-reformat) :type 'user-error)))
 
 (ert-deftest test-comment-reformat-elisp-read-only-buffer ()
   "Should signal error in read-only buffer."