Re: [PATCH 2/6] commit: add generation number to struct commmit
- From
Derrick Stolee <stolee@gmail.com>
- Date
- Apr 3, 2018, 18:31 UTC
- Message-ID
- <2b5a08da-6b15-194e-4336-ce7c84240a9b@gmail.com>
- In-Reply-To
- <20180403182800.GA8377@sigill.intra.peff.net>
On 4/3/2018 2:28 PM, Jeff King wrote:
Show 17 quoted lines
> On Tue, Apr 03, 2018 at 11:05:36AM -0700, Brandon Williams wrote: > >> On 04/03, Derrick Stolee wrote: >>> The generation number of a commit is defined recursively as follows: >>> >>> * If a commit A has no parents, then the generation number of A is one. >>> * If a commit A has parents, then the generation number of A is one >>> more than the maximum generation number among the parents of A. >>> >>> Add a uint32_t generation field to struct commit so we can pass this >> Is there any reason to believe this would be too small of a value in the >> future? Or is a 32 bit unsigned good enough? > The linux kernel took ~10 years to produce 500k commits. Even assuming > those were all linear (and they're not), that gives us ~80,000 years of > leeway. So even if the pace of development speeds up or we have a > quicker project, it still seems we have a pretty reasonable safety > margin.
That, and larger projects do not have linear histories. Despite having almost 2 million reachable commits, the Windows repository has maximum generation number ~100,000.
Thanks, -Stolee