patch 9.0.1740: segfault when reading invalid viminfo file

Problem: segfault when reading invalid viminfo file
Solution: Check the expected type in the viminfo file

Thanks to @yegappan for the included test.

closes: #12652
closes: #12845

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Pierre Colin <48397990+Pierre-Colin@users.noreply.github.com>
Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Co-authored-by: Christian Brabandt <cb@256bit.org>

src/testdir/test_viminfo.vim

@@ -614,6 +614,26 @@ func Test_viminfo_bad_syntax2()
   rviminfo Xviminfo
 endfunc
 
+" This used to crash Vim (GitHub issue #12652)
+func Test_viminfo_bad_syntax3()
+  let lines =<< trim END
+    call writefile([], 'Xvbs3.result')
+    qall!
+  END
+  call writefile(lines, 'Xvbs3script', 'D')
+
+  let lines = []
+  call add(lines, '|1,4')
+  " bad viminfo syntax for register barline
+  call add(lines, '|3,1,1,1,1,0,71489,,125') " empty line1
+  call writefile(lines, 'Xviminfo', 'D')
+
+  call RunVim([], [], '--clean -i Xviminfo -S Xvbs3script')
+  call assert_true(filereadable('Xvbs3.result'))
+
+  call delete('Xvbs3.result')
+endfunc
+
 func Test_viminfo_file_marks()
   silent! bwipe test_viminfo.vim
   silent! bwipe Xviminfo

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1740,
 /**/
     1739,
 /**/

src/viminfo.c

@@ -1804,6 +1804,11 @@ handle_viminfo_register(garray_T *values, int force)
 	    y_ptr->y_array[i] = vp[i + 6].bv_string;
 	    vp[i + 6].bv_string = NULL;
 	}
+        else if (vp[i + 6].bv_type != BVAL_STRING)
+        {
+            free(y_ptr->y_array);
+            y_ptr->y_array = NULL;
+        }
 	else
 	    y_ptr->y_array[i] = vim_strsave(vp[i + 6].bv_string);
     }