From: Junio C Hamano <gitster@pobox.com>
To: Patrick Steinhardt <ps@pks.im>
Cc: git@vger.kernel.org, Derrick Stolee <stolee@gmail.com>
Subject: Re: [PATCH v2] commit-graph: fix writing generations with dates exceeding 34 bits
Date: Tue, 24 Mar 2026 08:42:31 -0700 [thread overview]
Message-ID: <xmqq1ph92pzs.fsf@gitster.g> (raw)
In-Reply-To: <20260324-pks-commit-graph-overflow-v2-1-843568cf8780@pks.im> (Patrick Steinhardt's message of "Tue, 24 Mar 2026 07:18:26 +0100")
Patrick Steinhardt <ps@pks.im> writes:
> Changes in v2:
> - Account for platforms where `timestamp_t` has 32 bit precision. This
> matches logic in `write_graph_chunk_data()`, where we also depend on
> the size of the commit timestamps.
> +static timestamp_t compute_generation_offset(struct commit *c)
> +{
> + timestamp_t masked_date;
> +
> + if (sizeof(timestamp_t) > 4)
> + masked_date = c->date & (((timestamp_t) 1 << 34) - 1);
> + else
> + masked_date = c->date;
It is a bit surprising that on a platform where timestamp_t is only
32-bit wide, a smart-enough compiler would not find (1<<34) as
suspicious. IOW, I would have expected this to be done not with
runtime switch but with conditional compilation.
next prev parent reply other threads:[~2026-03-24 15:42 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-17 19:02 [PATCH] commit-graph: fix writing generations with dates exceeding 34 bits Patrick Steinhardt
2026-03-17 19:39 ` Junio C Hamano
2026-03-19 6:56 ` Patrick Steinhardt
2026-03-20 17:21 ` Derrick Stolee
2026-03-24 6:18 ` [PATCH v2] " Patrick Steinhardt
2026-03-24 15:42 ` Junio C Hamano [this message]
2026-03-25 5:36 ` Patrick Steinhardt
2026-03-26 10:02 ` Karthik Nayak
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