From a26cdcb20e68f38f636b14a03c3f9657f5c74f67 Mon Sep 17 00:00:00 2001
From: tao <2471314@gmail.com>
Date: Tue, 12 Aug 2025 06:39:03 +0800
Subject: [PATCH] fix(inccommand): skip input() during preview #35272

Problem:
During preview, the `input` still prompts the user to enter something
that won't be used later, which could be a bit confusing.
e.g., `:s/a/\=input("")`.

Solution:
Make the input() return early during 'inccommand' preview.
---
 src/nvim/ex_getln.c                    |  4 ++++
 test/functional/ui/inccommand_spec.lua | 12 ++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index 3c4e90f69d..56e34cb485 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -4819,6 +4819,10 @@ void get_user_input(const typval_T *const argvars, typval_T *const rettv, const
   rettv->v_type = VAR_STRING;
   rettv->vval.v_string = NULL;
 
+  if (cmdpreview) {
+    return;
+  }
+
   const char *prompt;
   const char *defstr = "";
   typval_T *cancelreturn = NULL;
diff --git a/test/functional/ui/inccommand_spec.lua b/test/functional/ui/inccommand_spec.lua
index 37dc0f5195..7f976ca5a4 100644
--- a/test/functional/ui/inccommand_spec.lua
+++ b/test/functional/ui/inccommand_spec.lua
@@ -2937,3 +2937,15 @@ it("'inccommand' disables preview if preview buffer can't be created #27086", fu
   ]])
   eq('nosplit', api.nvim_get_option_value('inccommand', {}))
 end)
+
+it(':substitute with inccommand, does not show prompt during preview #11940', function()
+  clear()
+  local screen = Screen.new(30, 3)
+  common_setup(screen, 'split', 'foo')
+  feed([[:s/f/\=input("sub: ")]])
+  screen:expect([[
+    oo                            |
+    {1:~                             }|
+    :s/f/\=input("sub: ")^         |
+  ]])
+end)