vim-patch:9.0.1524: passing -1 for bool is not always rejected

Problem:    Passing -1 for bool is not always rejected.
Solution:   Check for error in a better way. (closes vim/vim#12358)

https://github.com/vim/vim/commit/8cf51376b842e0060edf08bd2e5bd9933c552ecf

4 files changed, 29 insertions, 19 deletions

diff --git a/src/nvim/strings.c b/src/nvim/strings.c
index acbff51e49..4e521b14f7 100644
--- a/src/nvim/strings.c
+++ b/src/nvim/strings.c
@@ -1515,11 +1515,13 @@ static void byteidx_common(typval_T *argvars, typval_T *rettv, int comp)
 
   varnumber_T utf16idx = false;
   if (argvars[2].v_type != VAR_UNKNOWN) {
-    utf16idx = tv_get_bool(&argvars[2]);
+    bool error = false;
+    utf16idx = tv_get_bool_chk(&argvars[2], &error);
+    if (error) {
+      return;
+    }
     if (utf16idx < 0 || utf16idx > 1) {
-      if (utf16idx != -1) {
-        semsg(_(e_using_number_as_bool_nr), utf16idx);
-      }
+      semsg(_(e_using_number_as_bool_nr), utf16idx);
       return;
     }
   }
@@ -1767,18 +1769,21 @@ void f_strcharlen(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 /// "strchars()" function
 void f_strchars(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
-  int skipcc = false;
+  varnumber_T skipcc = false;
 
   if (argvars[1].v_type != VAR_UNKNOWN) {
-    skipcc = (int)tv_get_bool(&argvars[1]);
-  }
-  if (skipcc < 0 || skipcc > 1) {
-    if (skipcc != -1) {
+    bool error = false;
+    skipcc = tv_get_bool_chk(&argvars[1], &error);
+    if (error) {
+      return;
+    }
+    if (skipcc < 0 || skipcc > 1) {
       semsg(_(e_using_number_as_bool_nr), skipcc);
+      return;
     }
-  } else {
-    strchar_common(argvars, rettv, skipcc);
   }
+
+  strchar_common(argvars, rettv, skipcc);
 }
 
 /// "strutf16len()" function
@@ -1845,11 +1850,12 @@ void f_strcharpart(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   if (!error) {
     if (argvars[2].v_type != VAR_UNKNOWN
         && argvars[3].v_type != VAR_UNKNOWN) {
-      skipcc = tv_get_bool(&argvars[3]);
+      skipcc = tv_get_bool_chk(&argvars[3], &error);
+      if (error) {
+        return;
+      }
       if (skipcc < 0 || skipcc > 1) {
-        if (skipcc != -1) {
-          semsg(_(e_using_number_as_bool_nr), skipcc);
-        }
+        semsg(_(e_using_number_as_bool_nr), skipcc);
         return;
       }
     }
diff --git a/test/old/testdir/test_expr.vim b/test/old/testdir/test_expr.vim
index d771234983..4cb8da8c74 100644
--- a/test/old/testdir/test_expr.vim
+++ b/test/old/testdir/test_expr.vim
@@ -155,7 +155,8 @@ func Test_strcharpart()
   END
   call CheckLegacyAndVim9Success(lines)
 
-  call assert_fails('echo strcharpart("", 0, 0, {})', ['E728:', 'E728:'])
+  call assert_fails('call strcharpart("", 0, 0, {})', ['E728:', 'E728:'])
+  call assert_fails('call strcharpart("", 0, 0, -1)', ['E1023:', 'E1023:'])
 endfunc
 
 func Test_getreg_empty_list()
diff --git a/test/old/testdir/test_functions.vim b/test/old/testdir/test_functions.vim
index 6ff21bc859..41a8610893 100644
--- a/test/old/testdir/test_functions.vim
+++ b/test/old/testdir/test_functions.vim
@@ -1097,6 +1097,7 @@ func Test_byteidx()
   call assert_fails("call byteidx([], 0)", 'E730:')
   call assert_fails("call byteidx('abc', [])", 'E745:')
   call assert_fails("call byteidx('abc', 0, {})", ['E728:', 'E728:'])
+  call assert_fails("call byteidx('abc', 0, -1)", ['E1023:', 'E1023:'])
 endfunc
 
 " Test for byteidxcomp() using a character index
@@ -1137,6 +1138,7 @@ func Test_byteidxcomp()
   call assert_fails("call byteidxcomp([], 0)", 'E730:')
   call assert_fails("call byteidxcomp('abc', [])", 'E745:')
   call assert_fails("call byteidxcomp('abc', 0, {})", ['E728:', 'E728:'])
+  call assert_fails("call byteidxcomp('abc', 0, -1)", ['E1023:', 'E1023:'])
 endfunc
 
 " Test for byteidx() using a UTF-16 index
@@ -1497,7 +1499,6 @@ func Test_utf16idx_from_charidx()
   " error cases
   call assert_equal(-1, utf16idx(v:_null_string, 0, v:true, v:true))
   call assert_fails('let l = utf16idx("ab", 0, v:false, [])', 'E1212:')
-  call assert_fails('echo strchars("", {})', ['E728:', 'E728:'])
 endfunc
 
 " Test for strutf16len()
diff --git a/test/old/testdir/test_utf8.vim b/test/old/testdir/test_utf8.vim
index e5f6d68720..00b060a9e2 100644
--- a/test/old/testdir/test_utf8.vim
+++ b/test/old/testdir/test_utf8.vim
@@ -29,8 +29,10 @@ func Test_strchars()
     call assert_equal(exp[i], strcharlen(inp[i]))
   endfor
 
-  call assert_fails("let v=strchars('abc', [])", 'E745:')
-  call assert_fails("let v=strchars('abc', 2)", 'E1023:')
+  call assert_fails("call strchars('abc', 2)", ['E1023:', 'E1023:'])
+  call assert_fails("call strchars('abc', -1)", ['E1023:', 'E1023:'])
+  call assert_fails("call strchars('abc', {})", ['E728:', 'E728:'])
+  call assert_fails("call strchars('abc', [])", ['E745:', 'E745:'])
 endfunc
 
 " Test for customlist completion