From 23080a4d7a9043913cb4875e18118731a4562032 Mon Sep 17 00:00:00 2001
From: zeertzjq <zeertzjq@outlook.com>
Date: Sun, 30 Oct 2022 07:10:39 +0800
Subject: fix(mouse): ensure no scrolling with "ver:0" in 'mousescroll'
 (#20861)

---
 src/nvim/edit.c                              |  2 +-
 src/nvim/normal.c                            |  2 +-
 test/functional/options/mousescroll_spec.lua | 18 ++++++++++++++++++
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/nvim/edit.c b/src/nvim/edit.c
index 90a18947dd..c99449e0f3 100644
--- a/src/nvim/edit.c
+++ b/src/nvim/edit.c
@@ -4147,7 +4147,7 @@ static void ins_mousescroll(int dir)
     if (dir == MSCR_DOWN || dir == MSCR_UP) {
       if (mod_mask & (MOD_MASK_SHIFT | MOD_MASK_CTRL)) {
         scroll_redraw(dir, (long)(curwin->w_botline - curwin->w_topline));
-      } else {
+      } else if (p_mousescroll_vert > 0) {
         scroll_redraw(dir, p_mousescroll_vert);
       }
     } else {
diff --git a/src/nvim/normal.c b/src/nvim/normal.c
index e09fb149b4..3c49948b55 100644
--- a/src/nvim/normal.c
+++ b/src/nvim/normal.c
@@ -3417,7 +3417,7 @@ static void nv_mousescroll(cmdarg_T *cap)
   if (cap->arg == MSCR_UP || cap->arg == MSCR_DOWN) {
     if (mod_mask & (MOD_MASK_SHIFT | MOD_MASK_CTRL)) {
       (void)onepage(cap->arg ? FORWARD : BACKWARD, 1L);
-    } else {
+    } else if (p_mousescroll_vert > 0) {
       cap->count1 = p_mousescroll_vert;
       cap->count0 = p_mousescroll_vert;
       nv_scroll_line(cap);
diff --git a/test/functional/options/mousescroll_spec.lua b/test/functional/options/mousescroll_spec.lua
index 2c9b2d175e..5bff45a836 100644
--- a/test/functional/options/mousescroll_spec.lua
+++ b/test/functional/options/mousescroll_spec.lua
@@ -97,6 +97,24 @@ describe("'mousescroll'", function()
     eq(10, screencol())
     scroll('left')
     eq(10, screencol())
+
+    -- vertical scrolling is still disabled with non-zero 'scrolloff' value
+    command('set scrolloff=1')
+
+    eq(10, screenrow())
+    scroll('up')
+    eq(10, screenrow())
+    scroll('down')
+    eq(10, screenrow())
+
+    -- also in insert mode
+    feed('i')
+
+    eq(10, screenrow())
+    scroll('up')
+    eq(10, screenrow())
+    scroll('down')
+    eq(10, screenrow())
   end)
 
   local test_vertical_scrolling = function()
-- 
cgit