commit ad6c45f62558e03d3e3a927b3fe4dbaf30a36bef
author zeertzjq <zeertzjq@outlook.com> Sun Feb 20 19:05:10 2022 +0000
committer Bram Moolenaar <Bram@vim.org> Sun Feb 20 19:05:10 2022 +0000
tree e9619435354b3b6b9b4725c63c8cd99b6f3c295d
parent c1e6c7bafec1115b690c745a28e1a6338750b137

patch 8.2.4427: getchar() may return modifiers if no character is available

Problem:    getchar() may return modifiers if no character is available.
Solution:   Do not process modifiers when there is no character. (closes #9806)

src/getchar.c

diff --git a/src/getchar.c b/src/getchar.c
index 2068ca4..fcc9b9a 100644
--- a/src/getchar.c
+++ b/src/getchar.c
@@ -2103,7 +2103,7 @@
     set_vim_var_nr(VV_MOUSE_COL, 0);
 
     rettv->vval.v_number = n;
-    if (IS_SPECIAL(n) || mod_mask != 0)
+    if (n != 0 && (IS_SPECIAL(n) || mod_mask != 0))
     {
 	char_u		temp[10];   // modifier: 3, mbyte-char: 6, NUL: 1
 	int		i = 0;

src/testdir/test_functions.vim

diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index e2820db..e22a0c6 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -1818,6 +1818,10 @@
   call assert_equal('', getcharstr(0))
   call assert_equal('', getcharstr(1))
 
+  call feedkeys("\<M-F2>", '')
+  call assert_equal("\<M-F2>", getchar(0))
+  call assert_equal(0, getchar(0))
+
   call setline(1, 'xxxx')
   call test_setmouse(1, 3)
   let v:mouse_win = 9

src/version.c

diff --git a/src/version.c b/src/version.c
index 6c5ca2b..c5f5c22 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4427,
+/**/
     4426,
 /**/
     4425,