From 2ab47b08bd80bcf67dd70ba413971efa8e4b82f1 Mon Sep 17 00:00:00 2001
From: Kien Nguyen <kien.n.quang@gmail.com>
Date: Fri, 5 Jul 2024 22:01:35 -0700
Subject: [PATCH] ivy-completion-in-region: correctly calculate the length of
 replacement for file category

---
 ivy-test.el |  8 +++++++-
 ivy.el      | 23 ++++++++++++++++-------
 2 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/ivy-test.el b/ivy-test.el
index 87dda185..1afc4d8f 100644
--- a/ivy-test.el
+++ b/ivy-test.el
@@ -1012,6 +1012,11 @@ Since `execute-kbd-macro' doesn't pick up a let-bound `default-directory'.")
               #("test/"
                 0 2 (face completions-common-part)
                 2 3 (face (completions-first-difference))))))
+  (should (= 2
+             (ivy-completion-common-length
+              #("test/"
+                0 2 (face completions-common-part)
+                2 3 (face completions-first-difference)))))
   (should (= 5
              (ivy-completion-common-length
               #("Math/E"
@@ -1020,7 +1025,8 @@ Since `execute-kbd-macro' doesn't pick up a let-bound `default-directory'.")
   (should (= 3
              (ivy-completion-common-length
               #("vec"
-                0 3 (face (completions-common-part)))))))
+                0 3 (face (completions-common-part))))))
+  )
 
 (ert-deftest ivy--sort-function ()
   "Test `ivy--sort-function' behavior."
diff --git a/ivy.el b/ivy.el
index 5056d4e4..3b91ed27 100644
--- a/ivy.el
+++ b/ivy.el
@@ -2649,12 +2649,19 @@ The first non-matching part is propertized:
         (i (1- (length str))))
     (catch 'done
       (while (>= i 0)
-        (when (equal (get-text-property i 'face str)
-                     '(completions-first-difference))
-          (throw 'done i))
+        (pcase (get-text-property i 'face str)
+          (`completions-first-difference (throw 'done i))
+          ((and (pred listp) (pred (member 'completions-first-difference)))
+           (throw 'done i)))
         (cl-decf i))
       (throw 'done (length str)))))
 
+(defun ivy--completion-prefix-offset (str md)
+  "Return the offset of the completion prefix in STR with its metadata MD."
+  (pcase (cdr (assoc 'category md))
+    (`file (length (file-name-directory str)))
+    (_ 0)))
+
 (defun ivy-completion-in-region (start end collection &optional predicate)
   "An Ivy function suitable for `completion-in-region-function'.
 The function completes the text between START and END using COLLECTION.
@@ -2680,14 +2687,16 @@ See `completion-in-region' for further information."
            (when (eq collection 'crm--collection-fn)
              (setq comps (delete-dups comps)))
            (let* ((len (ivy-completion-common-length (car comps)))
+                  (prefix-offset (ivy--completion-prefix-offset str md))
+                  (target-str (substring str prefix-offset))
                   (initial (cond ((= len 0)
                                   "")
-                                 ((let ((str-len (length str)))
+                                 ((let ((str-len (length target-str)))
                                     (when (> len str-len)
-                                      (setq len str-len)
-                                      str)))
+                                      (setq len str-len)))
+                                  target-str)
                                  (t
-                                  (substring str (- len))))))
+                                  (substring target-str (- len))))))
              (delete-region (- end len) end)
              (setq ivy-completion-beg (- end len))
              (setq ivy-completion-end ivy-completion-beg)