patch 8.0.0841: term_getline() may cause a crash

Problem:    term_getline() may cause a crash.
Solution:   Check that the row is valid. (Hirohito Higashi)

Author: brammool

src/terminal.c

@@ -1847,6 +1847,8 @@ f_term_getline(typval_T *argvars, typval_T *rettv)
 	int		len;
 	char_u		*p;
 
+	if (row < 0 || row >= term->tl_rows)
+	    return;
 	len = term->tl_cols * MB_MAXBYTES + 1;
 	p = alloc(len);
 	if (p == NULL)

src/testdir/test_terminal.vim

@@ -81,6 +81,10 @@ func Test_terminal_hide_buffer()
 endfunc
 
 func Check_123(buf)
+  let l = term_scrape(a:buf, 0)
+  call assert_true(len(l) == 0)
+  let l = term_scrape(a:buf, 999)
+  call assert_true(len(l) == 0)
   let l = term_scrape(a:buf, 1)
   call assert_true(len(l) > 0)
   call assert_equal('1', l[0].chars)
@@ -93,6 +97,12 @@ func Check_123(buf)
     call assert_equal('#000000', l[0].bg)
   endif
 
+  let l = term_getline(a:buf, -1)
+  call assert_equal('', l)
+  let l = term_getline(a:buf, 0)
+  call assert_equal('', l)
+  let l = term_getline(a:buf, 999)
+  call assert_equal('', l)
   let l = term_getline(a:buf, 1)
   call assert_equal('123', l)
 endfunc

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    841,
 /**/
     840,
 /**/