rev-parse: demonstrate overflow of N for "foo^N" and "foo~N"

If the number gets too high for an int, weird things may happen, as signed overflows are undefined. Add a test to show this; rev-parse "sucessfully" interprets 100000000000000000000000000000000 to be the same as 0, at least on x64 with GCC 9.2.1 and Clang 8.0.1, which is obviously bogus. Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

René Scharfe committed Sep 15, 2019 at 14:03 UTC a678df1bf928caeeef642ef07f73484a580fea57
1 file changed +8
t/t1506-rev-parse-diagnosis.sh
+8
@@ -215,4 +215,12 @@ test_expect_success 'arg before dashdash must be a revision (ambiguous)' '
215 test_cmp expect actual
216 '
217
218 +test_expect_failure 'reject Nth parent if N is too high' '
219 + test_must_fail git rev-parse HEAD^100000000000000000000000000000000
220 +'
221 +
222 +test_expect_failure 'reject Nth ancestor if N is too high' '
223 + test_must_fail git rev-parse HEAD~100000000000000000000000000000000
224 +'
225 +
226 test_done