On 2/24/2022 5:35 PM, Junio C Hamano wrote:

"Derrick Stolee via GitGitGadget" [off-list ref] writes:

quoted

-			graph_data->generation = get_be64(g->chunk_generation_data_overflow + 8 * offset_pos);
+			graph_data->generation = item->date + get_be64(g->chunk_generation_data_overflow + 8 * offset_pos);

Wow, that's embarrassing.

quoted

diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index 1afee1c2705..5e4b0216fa6 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh

@@ -815,6 +815,19 @@ test_expect_success 'corrupt commit-graph write (missing tree)' '
 	)
 '
 
+# The remaining tests check timestamps that flow over
+# 32-bits. The graph_git_behavior checks can't take a
+# prereq, so just stop here if we are on a 32-bit machine.
+
+if ! test_have_prereq TIME_IS_64BIT
+then
+	test_done
+fi
+if ! test_have_prereq TIME_T_IS_64BIT
+then
+	test_done
+fi

The above is OK but is there a reason why we cannot do

	if A || B
	then
		test_done
	fi

here (I am assuming not, but in case I am missing the reason why it
has to be separate)?

Does not need to be separate. I just discovered the two different
prereqs for similar, but not exact, checks. I can swap this to an
or statement.
 

quoted

@@ -832,10 +845,10 @@ test_expect_success 'corrupt commit-graph write (missing tree)' '
 # The largest offset observed is 2 ^ 31, just large enough to overflow.
 #
 
-test_expect_success 'set up and verify repo with generation data overflow chunk' '
+test_expect_success TIME_IS_64BIT,TIME_T_IS_64BIT 'set up and verify repo with generation data overflow chunk' '
 	objdir=".git/objects" &&
 	UNIX_EPOCH_ZERO="@0 +0000" &&
-	FUTURE_DATE="@2147483646 +0000" &&
+	FUTURE_DATE="@4000000000 +0000" &&

OK. 16#EE6B2800 too large to fit and will cause wrapping around with
signed 32-bit integer.

Right. I wanted it to be right on that boundary of needing the 32nd
bit but not being over that on its own. I did check that without
the prereqs this code fails on 32-bit systems due to parsing the
time.

Thanks,
-Stolee