From: Abhishek Kumar <abhishekkumar8222@gmail.com> To: Derrick Stolee <stolee@gmail.com> Cc: abhishekkumar8222@gmail.com, git@vger.kernel.org, gitgitgadget@gmail.com, jnareb@gmail.com Subject: Re: [PATCH v3 11/11] doc: add corrected commit date info Date: Tue, 1 Sep 2020 18:31:52 +0530 Message-ID: <20200901130152.GA4186@Abhishek-Arch> (raw) In-Reply-To: <e7bbce30-93a6-b7e2-844b-5f2af4dbddf3@gmail.com> On Thu, Aug 27, 2020 at 09:15:56AM -0400, Derrick Stolee wrote: > On 8/27/2020 2:39 AM, Abhishek Kumar wrote: > > Thinking about this, I feel creating a new section called "Handling > > Mixed Generation Number Chains" made more sense: > > > > ## Handling Mixed Generation Number Chains > > > > With the introduction of generation number v2 and generation data chunk, > > the following scenario is possible: > > > > 1. "New" Git writes a commit-graph with a GDAT chunk. > > 2. "Old" Git writes a split commit-graph on top without a GDAT chunk. > > I like the idea of this section, and this setup is good. > > > The commits in the lower layer will be interpreted as having very large > > generation values (commit date plus offset) compared to the generation > > numbers in the top layer (toplogical level). This violates the > > expectation that the generation of a parent is strictly smaller than the > > generation of a child. In such cases, we revert to using topological > > levels for all layers to maintain backwards compatability. > > s/toplogical/topological > > But also, we don't want to phrase this as "in this case, we do the wrong > thing" but instead > > A naive approach of using the newest available generation number from > each layer would lead to violated expectations: the lower layer would > use corrected commit dates which are much larger than the topological > levels of the higher layer. For this reason, Git inspects each layer > to see if any layer is missing corrected commit dates. In such a case, > Git only uses topological levels. > > > When writing a new layer in split commit-graph, we write a GDAT chunk > > only if the topmost layer has a GDAT chunk. This guarantees that if a > > lyer has GDAT chunk, all lower layers must have a GDAT chunk as well. > > s/lyer/layer > > Perhaps leaving this at a higher level than referencing "GDAT chunk" is > advisable. Perhaps use "we write corrected commit dates" or "all lower > layers must store corrected commit dates as well", for example. > > > Rewriting layers follows similar approach: if the topmost layer below > > set of layers being rewriteen (in the split commit-graph chain) exists, > > and it does not contain GDAT chunk, then the result of rewrite does not > > have GDAT chunks either. > > This could use more positive language to make it clear that sometimes > we _do_ want to write corrected commit dates when merging layers: > > When merging layers, we do not consider whether the merged layers had > corrected commit dates. Instead, the new layer will have corrected > commit dates if and only if all existing layers below the new layer > have corrected commit dates. Thanks, that is a great suggestion! Using positive language is more straightforward and easier to understand. > > Thanks, > -Stolee
next prev parent reply other threads:[~2020-09-01 13:09 UTC|newest] Thread overview: 189+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-07-28 9:13 [PATCH 0/6] [GSoC] Implement Corrected Commit Date Abhishek Kumar via GitGitGadget 2020-07-28 9:13 ` [PATCH 1/6] commit-graph: fix regression when computing bloom filter Abhishek Kumar via GitGitGadget 2020-07-28 15:28 ` Taylor Blau 2020-07-30 5:24 ` Abhishek Kumar 2020-08-04 0:46 ` Jakub Narębski 2020-08-04 0:56 ` Taylor Blau 2020-08-04 10:10 ` Jakub Narębski 2020-08-04 7:55 ` Jakub Narębski 2020-07-28 9:13 ` [PATCH 2/6] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget 2020-07-28 13:00 ` Derrick Stolee 2020-07-28 15:30 ` Taylor Blau 2020-08-05 23:16 ` Jakub Narębski 2020-07-28 9:13 ` [PATCH 3/6] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget 2020-07-28 13:14 ` Derrick Stolee 2020-07-28 15:19 ` René Scharfe 2020-07-28 15:58 ` Derrick Stolee 2020-07-28 16:01 ` Taylor Blau 2020-07-30 6:07 ` Abhishek Kumar 2020-07-28 9:13 ` [PATCH 4/6] commit-graph: consolidate compare_commits_by_gen Abhishek Kumar via GitGitGadget 2020-07-28 16:03 ` Taylor Blau 2020-07-28 9:13 ` [PATCH 5/6] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget 2020-07-28 16:12 ` Taylor Blau 2020-07-30 6:52 ` Abhishek Kumar 2020-07-28 9:13 ` [PATCH 6/6] commit-graph: implement corrected commit date offset Abhishek Kumar via GitGitGadget 2020-07-28 15:55 ` Derrick Stolee 2020-07-28 16:23 ` Taylor Blau 2020-07-30 7:27 ` Abhishek Kumar 2020-07-28 14:54 ` [PATCH 0/6] [GSoC] Implement Corrected Commit Date Taylor Blau 2020-07-30 7:47 ` Abhishek Kumar 2020-07-28 16:35 ` Derrick Stolee 2020-08-09 2:53 ` [PATCH v2 00/10] " Abhishek Kumar via GitGitGadget 2020-08-09 2:53 ` [PATCH v2 01/10] commit-graph: fix regression when computing bloom filter Abhishek Kumar via GitGitGadget 2020-08-09 2:53 ` [PATCH v2 02/10] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget 2020-08-09 2:53 ` [PATCH v2 03/10] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget 2020-08-09 2:53 ` [PATCH v2 04/10] commit-graph: consolidate compare_commits_by_gen Abhishek Kumar via GitGitGadget 2020-08-09 2:53 ` [PATCH v2 05/10] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget 2020-08-10 16:28 ` Derrick Stolee 2020-08-11 11:03 ` Abhishek Kumar 2020-08-11 12:27 ` Derrick Stolee 2020-08-11 18:58 ` Taylor Blau 2020-08-09 2:53 ` [PATCH v2 06/10] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget 2020-08-09 2:53 ` [PATCH v2 07/10] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget 2020-08-10 14:23 ` Derrick Stolee 2020-08-14 4:59 ` Abhishek Kumar 2020-08-14 12:24 ` Derrick Stolee 2020-08-09 2:53 ` [PATCH v2 08/10] commit-graph: handle mixed generation commit chains Abhishek Kumar via GitGitGadget 2020-08-10 16:42 ` Derrick Stolee 2020-08-11 11:36 ` Abhishek Kumar 2020-08-11 12:43 ` Derrick Stolee 2020-08-09 2:53 ` [PATCH v2 09/10] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget 2020-08-09 2:53 ` [PATCH v2 10/10] doc: add corrected commit date info Abhishek Kumar via GitGitGadget 2020-08-10 16:47 ` [PATCH v2 00/10] [GSoC] Implement Corrected Commit Date Derrick Stolee 2020-08-15 16:39 ` [PATCH v3 00/11] " Abhishek Kumar via GitGitGadget 2020-08-15 16:39 ` [PATCH v3 01/11] commit-graph: fix regression when computing bloom filter Abhishek Kumar via GitGitGadget 2020-08-17 22:30 ` Jakub Narębski 2020-08-15 16:39 ` [PATCH v3 02/11] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget 2020-08-18 14:18 ` Jakub Narębski 2020-08-15 16:39 ` [PATCH v3 03/11] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget 2020-08-19 17:54 ` Jakub Narębski 2020-08-21 4:11 ` Abhishek Kumar 2020-08-25 11:11 ` Jakub Narębski 2020-09-01 11:35 ` Abhishek Kumar 2020-08-15 16:39 ` [PATCH v3 04/11] commit-graph: consolidate compare_commits_by_gen Abhishek Kumar via GitGitGadget 2020-08-17 13:22 ` Derrick Stolee 2020-08-21 11:05 ` Jakub Narębski 2020-08-15 16:39 ` [PATCH v3 05/11] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget 2020-08-21 13:14 ` Jakub Narębski 2020-08-25 5:04 ` Abhishek Kumar 2020-08-25 12:18 ` Jakub Narębski 2020-09-01 12:06 ` Abhishek Kumar 2020-09-03 13:42 ` Jakub Narębski 2020-09-05 17:21 ` Abhishek Kumar 2020-09-13 15:39 ` Jakub Narębski 2020-09-28 21:48 ` Jakub Narębski 2020-10-05 5:25 ` Abhishek Kumar 2020-08-15 16:39 ` [PATCH v3 06/11] commit-graph: add a slab to store topological levels Abhishek Kumar via GitGitGadget 2020-08-21 18:43 ` Jakub Narębski 2020-08-25 6:14 ` Abhishek Kumar 2020-08-25 7:33 ` Jakub Narębski 2020-08-25 7:56 ` Jakub Narębski 2020-09-01 10:26 ` Abhishek Kumar 2020-09-03 9:25 ` Jakub Narębski 2020-08-15 16:39 ` [PATCH v3 07/11] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget 2020-08-22 0:05 ` Jakub Narębski 2020-08-25 6:49 ` Abhishek Kumar 2020-08-25 10:07 ` Jakub Narębski 2020-09-01 11:01 ` Abhishek Kumar 2020-08-15 16:39 ` [PATCH v3 08/11] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget 2020-08-22 13:09 ` Jakub Narębski 2020-08-15 16:39 ` [PATCH v3 09/11] commit-graph: use generation v2 only if entire chain does Abhishek Kumar via GitGitGadget 2020-08-22 17:14 ` Jakub Narębski 2020-08-26 7:15 ` Abhishek Kumar 2020-08-26 10:38 ` Jakub Narębski 2020-08-15 16:39 ` [PATCH v3 10/11] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget 2020-08-22 19:09 ` Jakub Narębski 2020-09-01 10:08 ` Abhishek Kumar 2020-09-03 19:11 ` Jakub Narębski 2020-08-15 16:39 ` [PATCH v3 11/11] doc: add corrected commit date info Abhishek Kumar via GitGitGadget 2020-08-22 22:20 ` Jakub Narębski 2020-08-27 6:39 ` Abhishek Kumar 2020-08-27 12:43 ` Jakub Narębski 2020-08-27 13:15 ` Derrick Stolee 2020-09-01 13:01 ` Abhishek Kumar [this message] 2020-08-17 0:13 ` [PATCH v3 00/11] [GSoC] Implement Corrected Commit Date Jakub Narębski [not found] ` <CANQwDwdKp7oKy9BeKdvKhwPUiq0R5MS8TCw-eWGCYCoMGv=G-g@mail.gmail.com> 2020-08-17 1:32 ` Fwd: " Taylor Blau 2020-08-17 7:56 ` Jakub Narębski 2020-08-18 6:12 ` Abhishek Kumar 2020-08-23 15:27 ` Jakub Narębski 2020-08-24 2:49 ` Abhishek Kumar 2020-10-07 14:09 ` [PATCH v4 00/10] " Abhishek Kumar via GitGitGadget 2020-10-07 14:09 ` [PATCH v4 01/10] commit-graph: fix regression when computing Bloom filters Abhishek Kumar via GitGitGadget 2020-10-24 23:16 ` Jakub Narębski 2020-10-25 20:58 ` Taylor Blau 2020-11-03 5:36 ` Abhishek Kumar 2020-10-07 14:09 ` [PATCH v4 02/10] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget 2020-10-24 23:41 ` Jakub Narębski 2020-10-07 14:09 ` [PATCH v4 03/10] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget 2020-10-25 10:52 ` Jakub Narębski 2020-10-27 6:33 ` Abhishek Kumar 2020-10-07 14:09 ` [PATCH v4 04/10] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget 2020-10-25 13:48 ` Jakub Narębski 2020-11-03 6:40 ` Abhishek Kumar 2020-10-07 14:09 ` [PATCH v4 05/10] commit-graph: add a slab to store topological levels Abhishek Kumar via GitGitGadget 2020-10-25 22:17 ` Jakub Narębski 2020-10-07 14:09 ` [PATCH v4 06/10] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget 2020-10-27 18:53 ` Jakub Narębski 2020-11-03 11:44 ` Abhishek Kumar 2020-11-04 16:45 ` Jakub Narębski 2020-11-05 14:05 ` Philip Oakley 2020-11-05 18:22 ` Junio C Hamano 2020-11-06 18:26 ` Extending and updating gitglossary (was: Re: [PATCH v4 06/10] commit-graph: implement corrected commit date) Jakub Narębski 2020-11-06 19:33 ` Extending and updating gitglossary Junio C Hamano 2020-11-08 17:23 ` Extending and updating gitglossary (was: Re: [PATCH v4 06/10] commit-graph: implement corrected commit date) Philip Oakley 2020-11-10 1:35 ` Extending and updating gitglossary Jakub Narębski 2020-11-10 14:04 ` Philip Oakley 2020-11-10 23:52 ` Jakub Narębski 2020-10-07 14:09 ` [PATCH v4 07/10] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget 2020-10-30 12:45 ` Jakub Narębski 2020-11-06 11:25 ` Abhishek Kumar 2020-11-06 17:56 ` Jakub Narębski 2020-10-07 14:09 ` [PATCH v4 08/10] commit-graph: use generation v2 only if entire chain does Abhishek Kumar via GitGitGadget 2020-11-01 0:55 ` Jakub Narębski 2020-11-12 10:01 ` Abhishek Kumar 2020-11-13 9:59 ` Jakub Narębski 2020-10-07 14:09 ` [PATCH v4 09/10] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget 2020-11-03 17:59 ` Jakub Narębski 2020-11-03 18:19 ` Junio C Hamano 2020-11-20 10:33 ` Abhishek Kumar 2020-10-07 14:09 ` [PATCH v4 10/10] doc: add corrected commit date info Abhishek Kumar via GitGitGadget 2020-11-04 1:37 ` Jakub Narębski 2020-11-21 6:30 ` Abhishek Kumar 2020-11-04 23:37 ` [PATCH v4 00/10] [GSoC] Implement Corrected Commit Date Jakub Narębski 2020-11-22 5:31 ` Abhishek Kumar 2020-12-28 11:15 ` [PATCH v5 00/11] " Abhishek Kumar via GitGitGadget 2020-12-28 11:15 ` [PATCH v5 01/11] commit-graph: fix regression when computing Bloom filters Abhishek Kumar via GitGitGadget 2020-12-30 1:35 ` Derrick Stolee 2021-01-08 5:45 ` Abhishek Kumar 2021-01-05 9:45 ` SZEDER Gábor 2021-01-05 9:47 ` SZEDER Gábor 2021-01-08 5:51 ` Abhishek Kumar 2020-12-28 11:15 ` [PATCH v5 02/11] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget 2020-12-28 11:16 ` [PATCH v5 03/11] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget 2020-12-28 11:16 ` [PATCH v5 04/11] t6600-test-reach: generalize *_three_modes Abhishek Kumar via GitGitGadget 2020-12-28 11:16 ` [PATCH v5 05/11] commit-graph: add a slab to store topological levels Abhishek Kumar via GitGitGadget 2020-12-28 11:16 ` [PATCH v5 06/11] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget 2020-12-28 11:16 ` [PATCH v5 07/11] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget 2020-12-30 1:53 ` Derrick Stolee 2021-01-10 12:21 ` Abhishek Kumar 2020-12-28 11:16 ` [PATCH v5 08/11] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget 2020-12-28 11:16 ` [PATCH v5 09/11] commit-graph: use generation v2 only if entire chain does Abhishek Kumar via GitGitGadget 2020-12-30 3:23 ` Derrick Stolee 2021-01-10 13:13 ` Abhishek Kumar 2021-01-11 12:43 ` Derrick Stolee 2020-12-28 11:16 ` [PATCH v5 10/11] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget 2020-12-28 11:16 ` [PATCH v5 11/11] doc: add corrected commit date info Abhishek Kumar via GitGitGadget 2020-12-30 4:35 ` [PATCH v5 00/11] [GSoC] Implement Corrected Commit Date Derrick Stolee 2021-01-10 14:06 ` Abhishek Kumar 2021-01-16 18:11 ` [PATCH v6 " Abhishek Kumar via GitGitGadget 2021-01-16 18:11 ` [PATCH v6 01/11] commit-graph: fix regression when computing Bloom filters Abhishek Kumar via GitGitGadget 2021-01-16 18:11 ` [PATCH v6 02/11] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget 2021-01-16 18:11 ` [PATCH v6 03/11] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget 2021-01-16 18:11 ` [PATCH v6 04/11] t6600-test-reach: generalize *_three_modes Abhishek Kumar via GitGitGadget 2021-01-16 18:11 ` [PATCH v6 05/11] commit-graph: add a slab to store topological levels Abhishek Kumar via GitGitGadget 2021-01-16 18:11 ` [PATCH v6 06/11] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget 2021-01-16 18:11 ` [PATCH v6 07/11] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget 2021-01-16 18:11 ` [PATCH v6 08/11] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget 2021-01-16 18:11 ` [PATCH v6 09/11] commit-graph: use generation v2 only if entire chain does Abhishek Kumar via GitGitGadget 2021-01-16 18:11 ` [PATCH v6 10/11] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget 2021-01-16 18:11 ` [PATCH v6 11/11] doc: add corrected commit date info Abhishek Kumar via GitGitGadget
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