fix(options): disallow empty 'fdc' and 'scl' (#16776)

github-actions[bot] · web-flow · commit 37a00be7c0bf · 2021-12-24T22:38:15.000-07:00
Empty string values for these options aren't actually allowed, but
check_opt_strings allows empty string options.

It so happens that 'scl' handles empty string like "auto", but empty 'fdc'
causes glitchiness (win_fdccol_count returns an incorrect value).

Just disallow empty string values for these options completely.
diff --git a/src/nvim/option.c b/src/nvim/option.c
@@ -2953,7 +2953,7 @@ static char *did_set_string_option(int opt_idx, char_u **varp, bool new_value_al
     }
   } else if (varp == &curwin->w_p_fdc || varp == &curwin->w_allbuf_opt.wo_fdc) {
     // 'foldcolumn'
-    if (check_opt_strings(*varp, p_fdc_values, false) != OK) {
+    if (**varp == NUL || check_opt_strings(*varp, p_fdc_values, false) != OK) {
       errmsg = e_invarg;
     }
   } else if (varp == &p_pt) {
@@ -3332,6 +3332,9 @@ static int int_cmp(const void *a, const void *b)
 /// @return OK when the value is valid, FAIL otherwise
 int check_signcolumn(char_u *val)
 {
+  if (*val == NUL) {
+    return FAIL;
+  }
   // check for basic match
   if (check_opt_strings(val, p_scl_values, false) == OK) {
     return OK;
diff --git a/test/functional/legacy/options_spec.lua b/test/functional/legacy/options_spec.lua
@@ -83,4 +83,9 @@ describe('set', function()
       Press ENTER or type command to continue^   |
     ]])
   end)
+
+  it('foldcolumn and signcolumn to empty string is disallowed', function()
+    matches('E474: Invalid argument: fdc=', exc_exec('set fdc='))
+    matches('E474: Invalid argument: scl=', exc_exec('set scl='))
+  end)
 end)

Original file line number	Diff line number	Diff line change
`@@ -2953,7 +2953,7 @@ static char did_set_string_option(int opt_idx, char_u *varp, bool new_value_al`
`2953`	`2953`	`}`
`2954`	`2954`	`} else if (varp == &curwin->w_p_fdc \|\| varp == &curwin->w_allbuf_opt.wo_fdc) {`
`2955`	`2955`	`// 'foldcolumn'`
`2956`		`- if (check_opt_strings(*varp, p_fdc_values, false) != OK) {`
	`2956`	`+ if (*varp == NUL \|\| check_opt_strings(varp, p_fdc_values, false) != OK) {`
`2957`	`2957`	`errmsg = e_invarg;`
`2958`	`2958`	`}`
`2959`	`2959`	`} else if (varp == &p_pt) {`
`@@ -3332,6 +3332,9 @@ static int int_cmp(const void a, const void b)`
`3332`	`3332`	`/// @return OK when the value is valid, FAIL otherwise`
`3333`	`3333`	`int check_signcolumn(char_u *val)`
`3334`	`3334`	`{`
	`3335`	`+ if (*val == NUL) {`
	`3336`	`+ return FAIL;`
	`3337`	`+ }`
`3335`	`3338`	`// check for basic match`
`3336`	`3339`	`if (check_opt_strings(val, p_scl_values, false) == OK) {`
`3337`	`3340`	`return OK;`