From 99880f96cf444014d589fc1d99bb164deaba71ce Mon Sep 17 00:00:00 2001
From: Bram Moolenaar <Bram@vim.org>
Date: Wed, 20 Jan 2021 21:23:14 +0100
Subject: patch 8.2.2378: Vim9: no error message for dividing by zero

Problem:    Vim9: no error message for dividing by zero.
Solution:   Give an error message. (issue #7704)
---
 src/errors.h                   |  2 ++
 src/eval.c                     |  7 +++++--
 src/testdir/test_vim9_expr.vim |  5 +++--
 src/version.c                  |  2 ++
 src/vim9execute.c              | 10 ++++++++--
 5 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/src/errors.h b/src/errors.h
index eb5ee1de2e..4bd4efea69 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -343,3 +343,5 @@ EXTERN char e_mismatched_enddef[]
 	INIT(= N_("E1152: Mismatched enddef"));
 EXTERN char e_invalid_operation_for_bool[]
 	INIT(= N_("E1153: Invalid operation for bool"));
+EXTERN char e_divide_by_zero[]
+	INIT(= N_("E1154: Divide by zero"));
diff --git a/src/eval.c b/src/eval.c
index 13ee49aac4..40c6feb706 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -63,8 +63,10 @@ num_divide(varnumber_T n1, varnumber_T n2)
 {
     varnumber_T	result;
 
-    if (n2 == 0)	// give an error message?
+    if (n2 == 0)
     {
+	if (in_vim9script())
+	    emsg(_(e_divide_by_zero));
 	if (n1 == 0)
 	    result = VARNUM_MIN; // similar to NaN
 	else if (n1 < 0)
@@ -84,7 +86,8 @@ num_divide(varnumber_T n1, varnumber_T n2)
 	varnumber_T
 num_modulus(varnumber_T n1, varnumber_T n2)
 {
-    // Give an error when n2 is 0?
+    if (n2 == 0 && in_vim9script())
+	emsg(_(e_divide_by_zero));
     return (n2 == 0) ? 0 : (n1 % n2);
 }
 
diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
index c81468cb36..2239e76df9 100644
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -1376,7 +1376,6 @@ def Test_expr6()
       assert_equal(1, g:anint / 6)
       assert_equal(2, g:anint
                             / g:thefour)
-      assert_true(1 / 0 > 99999)
 
       assert_equal(5, 11 % 6)
       assert_equal(4, g:anint % 6)
@@ -1384,7 +1383,6 @@ def Test_expr6()
                             g:anint)
       assert_equal(2, g:anint
                             % g:thefour)
-      assert_equal(0, 1 % 0)
 
       assert_equal(4, 6 * 4 / 6)
 
@@ -1405,6 +1403,9 @@ def Test_expr6()
 
   CheckDefFailure(["var x = 6 * xxx"], 'E1001:', 1)
   CheckDefFailure(["var d = 6 * "], 'E1097:', 3)
+
+  CheckDefExecAndScriptFailure(['echo 1 / 0'], 'E1154', 1)
+  CheckDefExecAndScriptFailure(['echo 1 % 0'], 'E1154', 1)
 enddef
 
 def Test_expr6_vim9script()
diff --git a/src/version.c b/src/version.c
index 57b1a0c474..5668f75546 100644
--- a/src/version.c
+++ b/src/version.c
@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2378,
 /**/
     2377,
 /**/
diff --git a/src/vim9execute.c b/src/vim9execute.c
index 907a52f18f..b1bc282636 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -2954,10 +2954,16 @@ call_def_function(
 			switch (iptr->isn_arg.op.op_type)
 			{
 			    case EXPR_MULT: n1 = n1 * n2; break;
-			    case EXPR_DIV:  n1 = num_divide(n1, n2); break;
+			    case EXPR_DIV:  n1 = num_divide(n1, n2);
+					    if (n2 == 0)
+						goto on_error;
+					    break;
 			    case EXPR_SUB:  n1 = n1 - n2; break;
 			    case EXPR_ADD:  n1 = n1 + n2; break;
-			    default:	    n1 = num_modulus(n1, n2); break;
+			    default:	    n1 = num_modulus(n1, n2);
+					    if (n2 == 0)
+						goto on_error;
+					    break;
 			}
 			clear_tv(tv1);
 			clear_tv(tv2);
-- 
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