Add assertion for hash values of rows.

 src/dispnew.c (add_row_entry): Add xassert to verify that ROW's hash code
 is valid.

2 files changed, 2 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index b394c37354f..9af953b08b1 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -4,6 +4,7 @@
         hash values of the two rows.
         (copy_row_except_pointers): Preserve the used[] arrays and the
         hash values of the two rows.  (Bug#10035)
+        (add_row_entry): Add xassert to verify that ROW's hash code is valid.
 
         * xdisp.c (row_hash): New function, body extracted from
         compute_line_metrics.
diff --git a/src/dispnew.c b/src/dispnew.c
index 07843d3e214..d6bf6666ee2 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -4240,6 +4240,7 @@ add_row_entry (struct glyph_row *row)
   ptrdiff_t i = row->hash % row_table_size;
 
   entry = row_table[i];
+  xassert (entry || verify_row_hash (row));
   while (entry && !row_equal_p (entry->row, row, 1))
     entry = entry->next;