On 3/1/2022 9:53 AM, Patrick Steinhardt wrote: > On Tue, Mar 01, 2022 at 09:06:44AM -0500, Derrick Stolee wrote: >> On 3/1/2022 5:35 AM, Patrick Steinhardt wrote: >>> On Tue, Mar 01, 2022 at 10:46:14AM +0100, Patrick Steinhardt wrote: >>>> On Mon, Feb 28, 2022 at 01:44:01PM -0500, Derrick Stolee wrote: >>>>> On 2/28/2022 11:59 AM, Patrick Steinhardt wrote: >>>>>> On Mon, Feb 28, 2022 at 11:23:38AM -0500, Derrick Stolee wrote: >>>>>>> On 2/28/2022 10:18 AM, Patrick Steinhardt wrote: >>>>>>>> [1]: https://gitlab.com/gitlab-com/www-gitlab-com.git ... >>> So the question is whether this is a change that needs to be rolled out >>> over multiple releases. First we'd get in the bug fix such that we write >>> correct commit-graphs, and after this fix has been released we can also >>> release the fix that starts to actually parse the generation. This >>> ensures there's a grace period during which we can hopefully correct the >>> data on-disk such that users are not faced with failures. >> >> You are right that we need to be careful here, but I also think that >> previous versions of Git always wrote the correct data. Here is my >> thought process: >> >> 1. To get this bug, we need to have parsed the corrected commit date >> from an existing commit-graph in order to under-count the number >> of overflow values. >> >> 2. Before this series, Git versions were not parsing the corrected >> commit date, so they recompute the corrected commit date every >> time the commit-graph is written, getting the proper count of >> overflow values. >> >> For these reasons, data written by previous versions of Git are >> correct and can be trusted without a staged release. >> >> Does this make sense? Or, do you experience a different result when >> you build commit-graphs with a released Git version and then when >> writing on top with all patches applied? > > Just to verify my understanding: you claim that the bug I was hitting > shouldn't be encountered in the wild when the release , but > only if one were to write a commit-graph with the intermediate stafe > until patch 3/4 of your patch series? That is my claim. And my testing of the repo at [1] has demonstrated that it works correctly in these cases. > Hum. I have re-verified, and this indeed seems to play out. So I must've > accidentally ran all my testing with the state generated without the > final patch which fixes the corruption. I do see lots of the following > warnings, but overall I can verify and write the commit-graph just fine: > > commit-graph generation for commit c80a42de8803e2d77818d0c82f88e748d7f9425f is 1623362063 < 1623362139 But I'm not able to generate these warnings from either version. I tried generating different levels of a split commit-graph, but could not reproduce it. If you have reproduction steps using current 'master' (or any released Git version) and the four patches here, then I would love to get a full understanding of your errors. Thanks, -Stolee
