patch 9.0.1723: Fix regression in {func} argument of reduce()

Problem: Fix regression in {func} argument of reduce()
Solution: pass function name as string again

Before patch 9.0.0548, passing a string as {func} argument of reduce()
is treated as a function name, but after patch 9.0.0548 it is treated as
an expression instead, which is useless as reduce() doesn't set any v:
variables. This PR restores the behavior of {func} before that patch.

Also correct an emsg() call, as e_string_list_or_blob_required doesn't
contain format specifiers.

closes: #12824

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: zeertzjq <zeertzjq@outlook.com>

src/blob.c

@@ -769,7 +769,7 @@ blob_reduce(
 	argv[1].v_type = VAR_NUMBER;
 	argv[1].vval.v_number = blob_get(b, i);
 
-	r = eval_expr_typval(expr, argv, 2, NULL, rettv);
+	r = eval_expr_typval(expr, TRUE, argv, 2, NULL, rettv);
 
 	clear_tv(&argv[0]);
 	if (r == FAIL || called_emsg != called_emsg_start)

src/eval.c

@@ -252,12 +252,14 @@ eval_expr_get_funccal(typval_T *expr, typval_T *rettv)
 /*
  * Evaluate an expression, which can be a function, partial or string.
  * Pass arguments "argv[argc]".
+ * If "want_func" is TRUE treat a string as a function name, not an expression.
  * "fc_arg" is from eval_expr_get_funccal() or NULL;
  * Return the result in "rettv" and OK or FAIL.
  */
     int
 eval_expr_typval(
 	typval_T    *expr,
+	int	    want_func,
 	typval_T    *argv,
 	int	    argc,
 	funccall_T  *fc_arg,
@@ -267,17 +269,7 @@ eval_expr_typval(
     char_u	buf[NUMBUFLEN];
     funcexe_T	funcexe;
 
-    if (expr->v_type == VAR_FUNC)
+    if (expr->v_type == VAR_PARTIAL)
-    {
-	s = expr->vval.v_string;
-	if (s == NULL || *s == NUL)
-	    return FAIL;
-	CLEAR_FIELD(funcexe);
-	funcexe.fe_evaluate = TRUE;
-	if (call_func(s, -1, rettv, argc, argv, &funcexe) == FAIL)
-	    return FAIL;
-    }
-    else if (expr->v_type == VAR_PARTIAL)
     {
 	partial_T   *partial = expr->vval.v_partial;
 
@@ -318,6 +310,18 @@ eval_expr_typval(
     {
 	return exe_typval_instr(expr, rettv);
     }
+    else if (expr->v_type == VAR_FUNC || want_func)
+    {
+	s = expr->v_type == VAR_FUNC
+		? expr->vval.v_string
+		: tv_get_string_buf_chk_strict(expr, buf, in_vim9script());
+	if (s == NULL || *s == NUL)
+	    return FAIL;
+	CLEAR_FIELD(funcexe);
+	funcexe.fe_evaluate = TRUE;
+	if (call_func(s, -1, rettv, argc, argv, &funcexe) == FAIL)
+	    return FAIL;
+    }
     else
     {
 	s = tv_get_string_buf_chk_strict(expr, buf, in_vim9script());
@@ -346,7 +350,7 @@ eval_expr_to_bool(typval_T *expr, int *error)
     typval_T	rettv;
     int		res;
 
-    if (eval_expr_typval(expr, NULL, 0, NULL, &rettv) == FAIL)
+    if (eval_expr_typval(expr, FALSE, NULL, 0, NULL, &rettv) == FAIL)
     {
 	*error = TRUE;
 	return FALSE;

src/evalfunc.c

@@ -6938,7 +6938,7 @@ indexof_eval_expr(typval_T *expr)
     argv[1] = *get_vim_var_tv(VV_VAL);
     newtv.v_type = VAR_UNKNOWN;
 
-    if (eval_expr_typval(expr, argv, 2, NULL, &newtv) == FAIL)
+    if (eval_expr_typval(expr, FALSE, argv, 2, NULL, &newtv) == FAIL)
 	return FALSE;
 
     found = tv_get_bool_chk(&newtv, &error);

src/filepath.c

@@ -1616,7 +1616,7 @@ checkitem_common(void *context, char_u *name, dict_T *dict)
 	argv[0].vval.v_dict = dict;
     }
 
-    if (eval_expr_typval(expr, argv, 1, NULL, &rettv) == FAIL)
+    if (eval_expr_typval(expr, FALSE, argv, 1, NULL, &rettv) == FAIL)
 	goto theend;
 
     // We want to use -1, but also true/false should be allowed.

src/list.c

@@ -2333,7 +2333,7 @@ filter_map_one(
     copy_tv(tv, get_vim_var_tv(VV_VAL));
     argv[0] = *get_vim_var_tv(VV_KEY);
     argv[1] = *get_vim_var_tv(VV_VAL);
-    if (eval_expr_typval(expr, argv, 2, fc, newtv) == FAIL)
+    if (eval_expr_typval(expr, FALSE, argv, 2, fc, newtv) == FAIL)
 	goto theend;
     if (filtermap == FILTERMAP_FILTER)
     {
@@ -3084,7 +3084,7 @@ list_reduce(
 	else
 	    argv[1] = li->li_tv;
 
-	r = eval_expr_typval(expr, argv, 2, fc, rettv);
+	r = eval_expr_typval(expr, TRUE, argv, 2, fc, rettv);
 
 	if (argv[0].v_type != VAR_NUMBER && argv[0].v_type != VAR_UNKNOWN)
 	    clear_tv(&argv[0]);
@@ -3125,7 +3125,7 @@ f_reduce(typval_T *argvars, typval_T *rettv)
 	    && argvars[0].v_type != VAR_LIST
 	    && argvars[0].v_type != VAR_BLOB)
     {
-	semsg(_(e_string_list_or_blob_required), "reduce()");
+	emsg(_(e_string_list_or_blob_required));
 	return;
     }
 

src/proto/eval.pro

@@ -7,7 +7,7 @@ void fill_evalarg_from_eap(evalarg_T *evalarg, exarg_T *eap, int skip);
 int eval_to_bool(char_u *arg, int *error, exarg_T *eap, int skip, int use_simple_function);
 int eval_expr_valid_arg(typval_T *tv);
 funccall_T *eval_expr_get_funccal(typval_T *expr, typval_T *rettv);
-int eval_expr_typval(typval_T *expr, typval_T *argv, int argc, funccall_T *fc_arg, typval_T *rettv);
+int eval_expr_typval(typval_T *expr, int prefer_func, typval_T *argv, int argc, funccall_T *fc_arg, typval_T *rettv);
 int eval_expr_to_bool(typval_T *expr, int *error);
 char_u *eval_to_string_skip(char_u *arg, exarg_T *eap, int skip);
 void init_evalarg(evalarg_T *evalarg);

src/strings.c

@@ -1032,7 +1032,7 @@ string_reduce(
 	    break;
 	len = (int)STRLEN(argv[1].vval.v_string);
 
-	r = eval_expr_typval(expr, argv, 2, fc, rettv);
+	r = eval_expr_typval(expr, TRUE, argv, 2, fc, rettv);
 
 	clear_tv(&argv[0]);
 	clear_tv(&argv[1]);

src/testdir/test_listdict.vim

@@ -1037,6 +1037,10 @@ func Test_reduce()
       call assert_equal('Å,s,t,r,ö,m', reduce('Åström', LSTART acc, val LMIDDLE acc .. ',' .. val LEND))
       call assert_equal('Å,s,t,r,ö,m', reduce('Åström', LSTART acc, val LMIDDLE acc .. ',' .. val LEND))
       call assert_equal(',a,b,c', reduce('abc', LSTART acc, val LMIDDLE acc .. ',' .. val LEND, test_null_string()))
+
+      call assert_equal(0x7d, reduce([0x30, 0x25, 0x08, 0x61], 'or'))
+      call assert_equal(0x7d, reduce(0z30250861, 'or'))
+      call assert_equal('β', reduce('ββββ', 'matchstr'))
   END
   call v9.CheckLegacyAndVim9Success(lines)
 
@@ -1052,7 +1056,7 @@ func Test_reduce()
 
   call assert_fails("call reduce({}, { acc, val -> acc + val }, 1)", 'E1098:')
   call assert_fails("call reduce(0, { acc, val -> acc + val }, 1)", 'E1098:')
-  call assert_fails("call reduce([1, 2], 'Xdoes_not_exist')", 'E121:')
+  call assert_fails("call reduce([1, 2], 'Xdoes_not_exist')", 'E117:')
   call assert_fails("echo reduce(0z01, { acc, val -> 2 * acc + val }, '')", 'E1210:')
 
   call assert_fails("vim9 reduce(0, (acc, val) => (acc .. val), '')", 'E1252:')

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1723,
 /**/
     1722,
 /**/