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From: Derrick Stolee <derrickstolee@github.com>
To: Jonathan Tan <jonathantanmy@google.com>, git@vger.kernel.org
Cc: Ramsay Jones <ramsay@ramsayjones.plus.com>,
	Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH v4 3/4] repo-settings: introduce commitgraph.changedPathsVersion
Date: Tue, 20 Jun 2023 09:28:02 -0400	[thread overview]
Message-ID: <ceb8eb58-6cbe-1846-14e4-33c4967e3024@github.com> (raw)
In-Reply-To: <6adfa53dafc8c34f94a017fdc08460911f53d310.1686677910.git.jonathantanmy@google.com>

On 6/13/2023 1:39 PM, Jonathan Tan wrote:
> A subsequent commit will introduce another version of the changed-path
> filter in the commit graph file. In order to control which version is
> to be accepted when read (and which version to write), a config variable
> is needed.
> 
> Therefore, introduce this config variable. For forwards compatibility,
> teach Git to not read commit graphs when the config variable
> is set to an unsupported version. Because we teach Git this,
> commitgraph.readChangedPaths is now redundant, so deprecate it and
> define its behavior in terms of the config variable we introduce.

I'm late to the party, but I support this change. The safety valve
of "I want to turn this off if something goes wrong" is long overdue
for deletion (it would help someone in this high-bit situation).

Having a new replacement is a good way to preserve the safety valve
behavior while also promoting the new versioning scheme.
 
> This commit does not change the behavior of writing (Git writes changed
> path filters when explicitly instructed regardless of any config
> variable), but a subsequent commit will restrict Git such that it will
> only write when commitgraph.changedPathsVersion is 0, 1, or 2.

>  commitGraph.readChangedPaths::
> -	If true, then git will use the changed-path Bloom filters in the
> -	commit-graph file (if it exists, and they are present). Defaults to
> -	true. See linkgit:git-commit-graph[1] for more information.
> +	Deprecated. Equivalent to changedPathsVersion=1 if true, and
> +	changedPathsVersion=0 if false.

This defaulted to true before...

> +commitGraph.changedPathsVersion::
> +	Specifies the version of the changed-path Bloom filters that Git will read and
> +	write. May be 0 or 1. Any changed-path Bloom filters on disk that do not
> +	match the version set in this config variable will be ignored.
> ++
> +Defaults to 1.

So this version defaults to 1. Good.

> ++
> +If 0, git will write version 1 Bloom filters when instructed to write.

> -	if (s->commit_graph_read_changed_paths) {
> +	if (s->commit_graph_changed_paths_version == 1) {
>  		pair_chunk(cf, GRAPH_CHUNKID_BLOOMINDEXES,
>  			   &graph->chunk_bloom_indexes);
>  		read_chunk(cf, GRAPH_CHUNKID_BLOOMDATA,


>  	/* Commit graph config or default, does not cascade (simple) */
>  	repo_cfg_bool(r, "core.commitgraph", &r->settings.core_commit_graph, 1);
>  	repo_cfg_int(r, "commitgraph.generationversion", &r->settings.commit_graph_generation_version, 2);
> -	repo_cfg_bool(r, "commitgraph.readchangedpaths", &r->settings.commit_graph_read_changed_paths, 1);
> +	repo_cfg_bool(r, "commitgraph.readchangedpaths", &readChangedPaths, 1);
> +	repo_cfg_int(r, "commitgraph.changedpathsversion",
> +		     &r->settings.commit_graph_changed_paths_version,
> +		     readChangedPaths ? 1 : 0);

And here we default to 'true' and '1', respectively. This allows 
'commitGraph.readChangedPaths=false' to override
'commitGraph.changedPathsVersion=1'. Should that implication be
documented?

Thanks,
-Stolee

  reply	other threads:[~2023-06-20 13:28 UTC|newest]

Thread overview: 116+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-22 21:48 [PATCH 0/2] Changed path filter hash fix and version bump Jonathan Tan
2023-05-22 21:48 ` [PATCH 1/2] t4216: test wrong bloom filter version rejection Jonathan Tan
2023-05-22 21:48 ` [PATCH 2/2] commit-graph: fix murmur3, bump filter ver. to 2 Jonathan Tan
2023-05-23 13:00   ` Derrick Stolee
2023-05-23 23:00     ` Jonathan Tan
2023-05-23 23:51     ` Junio C Hamano
2023-05-24 21:26       ` Jonathan Tan
2023-05-26 13:19         ` Derrick Stolee
2023-05-30 17:26           ` Jonathan Tan
2023-05-23  4:42 ` [PATCH 0/2] Changed path filter hash fix and version bump Junio C Hamano
2023-05-31 23:12 ` [PATCH v2 0/3] " Jonathan Tan
2023-05-31 23:12   ` [PATCH v2 1/3] t4216: test changed path filters with high bit paths Jonathan Tan
2023-05-31 23:12   ` [PATCH v2 2/3] repo-settings: introduce commitgraph.changedPathsVersion Jonathan Tan
2023-05-31 23:12   ` [PATCH v2 3/3] commit-graph: new filter ver. that fixes murmur3 Jonathan Tan
2023-06-03  1:01   ` [PATCH v2 0/3] Changed path filter hash fix and version bump Junio C Hamano
2023-06-03  2:24     ` Junio C Hamano
2023-06-07 16:30       ` Jonathan Tan
2023-06-07 21:37         ` Jonathan Tan
2023-06-08 19:21 ` [PATCH v3 0/4] " Jonathan Tan
2023-06-08 19:21   ` [PATCH v3 1/4] gitformat-commit-graph: describe version 2 of BDAT Jonathan Tan
2023-06-08 19:52     ` Ramsay Jones
2023-06-12 21:26       ` Junio C Hamano
2023-06-08 19:21   ` [PATCH v3 2/4] t4216: test changed path filters with high bit paths Jonathan Tan
2023-06-08 19:21   ` [PATCH v3 3/4] repo-settings: introduce commitgraph.changedPathsVersion Jonathan Tan
2023-06-08 19:21   ` [PATCH v3 4/4] commit-graph: new filter ver. that fixes murmur3 Jonathan Tan
2023-06-08 19:50   ` [PATCH v3 0/4] Changed path filter hash fix and version bump Ramsay Jones
2023-06-09  0:08     ` Jonathan Tan
2023-06-12 21:31     ` Junio C Hamano
2023-06-13 17:16       ` Jonathan Tan
2023-06-13 17:29         ` [PATCH] CodingGuidelines: use octal escapes, not hex Jonathan Tan
2023-06-13 18:16           ` Eric Sunshine
2023-06-13 18:43             ` Jonathan Tan
2023-06-13 19:15               ` Eric Sunshine
2023-06-13 19:29                 ` Junio C Hamano
2023-06-13 19:16         ` [PATCH v3 0/4] Changed path filter hash fix and version bump Junio C Hamano
2023-06-13 17:39 ` [PATCH v4 " Jonathan Tan
2023-06-13 17:39   ` [PATCH v4 1/4] gitformat-commit-graph: describe version 2 of BDAT Jonathan Tan
2023-06-13 21:58     ` Junio C Hamano
2023-06-20 13:22       ` Derrick Stolee
2023-06-21 12:08       ` Taylor Blau
2023-06-22 22:26         ` Jonathan Tan
2023-06-23 13:05           ` Derrick Stolee
2023-06-13 17:39   ` [PATCH v4 2/4] t4216: test changed path filters with high bit paths Jonathan Tan
2023-06-13 17:39   ` [PATCH v4 3/4] repo-settings: introduce commitgraph.changedPathsVersion Jonathan Tan
2023-06-20 13:28     ` Derrick Stolee [this message]
2023-06-21 12:14     ` Taylor Blau
2023-06-13 17:39   ` [PATCH v4 4/4] commit-graph: new filter ver. that fixes murmur3 Jonathan Tan
2023-06-20 13:39     ` Derrick Stolee
2023-06-20 18:37       ` Junio C Hamano
2023-06-13 19:21   ` [PATCH v4 0/4] Changed path filter hash fix and version bump Junio C Hamano
2023-06-20 13:43     ` Derrick Stolee
2023-06-20 21:56       ` Jonathan Tan
2023-06-21 12:19       ` Taylor Blau
2023-06-21 17:53         ` Derrick Stolee
2023-06-22 22:27           ` Jonathan Tan
2023-06-23 13:18             ` Derrick Stolee
2023-07-13 21:42 ` [PATCH v5 " Jonathan Tan
2023-07-13 21:42   ` [PATCH v5 1/4] gitformat-commit-graph: describe version 2 of BDAT Jonathan Tan
2023-07-19 17:25     ` Taylor Blau
2023-07-20 20:20       ` Jonathan Tan
2023-07-21  1:38         ` Taylor Blau
2023-07-13 21:42   ` [PATCH v5 2/4] t4216: test changed path filters with high bit paths Jonathan Tan
2023-07-13 22:50     ` Junio C Hamano
2023-07-19 17:27       ` Taylor Blau
2023-07-19 17:55         ` [PATCH 0/4] commit-graph: avoid looking at Bloom filter data directly Taylor Blau
2023-07-19 17:55           ` [PATCH 1/4] t/helper/test-read-graph.c: extract `dump_graph_info()` Taylor Blau
2023-07-19 17:55           ` [PATCH 2/4] bloom.h: make `load_bloom_filter_from_graph()` public Taylor Blau
2023-07-19 17:55           ` [PATCH 3/4] t/helper/test-read-graph: implement `bloom-filters` mode Taylor Blau
2023-07-19 17:55           ` [PATCH 4/4] fixup! t4216: test changed path filters with high bit paths Taylor Blau
2023-07-19 19:24           ` [PATCH 0/4] commit-graph: avoid looking at Bloom filter data directly Junio C Hamano
2023-07-20 20:22           ` Jonathan Tan
2023-07-13 21:42   ` [PATCH v5 3/4] repo-settings: introduce commitgraph.changedPathsVersion Jonathan Tan
2023-07-19 18:10     ` Taylor Blau
2023-07-20 20:42       ` Jonathan Tan
2023-07-20 21:02         ` Taylor Blau
2023-07-13 21:42   ` [PATCH v5 4/4] commit-graph: new filter ver. that fixes murmur3 Jonathan Tan
2023-07-19 18:24     ` Taylor Blau
2023-07-20 21:27       ` Jonathan Tan
2023-07-26 23:32         ` Taylor Blau
2023-07-13 22:16   ` [PATCH v5 0/4] Changed path filter hash fix and version bump Junio C Hamano
2023-07-13 22:59     ` Junio C Hamano
2023-07-14 18:48     ` Jonathan Tan
2023-07-20 21:46 ` [PATCH v6 0/7] " Jonathan Tan
2023-07-20 21:46   ` [PATCH v6 1/7] gitformat-commit-graph: describe version 2 of BDAT Jonathan Tan
2023-07-20 21:46   ` [PATCH v6 2/7] t/helper/test-read-graph.c: extract `dump_graph_info()` Jonathan Tan
2023-07-26 23:26     ` Taylor Blau
2023-07-20 21:46   ` [PATCH v6 3/7] bloom.h: make `load_bloom_filter_from_graph()` public Jonathan Tan
2023-07-20 21:46   ` [PATCH v6 4/7] t/helper/test-read-graph: implement `bloom-filters` mode Jonathan Tan
2023-07-20 21:46   ` [PATCH v6 5/7] t4216: test changed path filters with high bit paths Jonathan Tan
2023-07-26 23:28     ` Taylor Blau
2023-07-20 21:46   ` [PATCH v6 6/7] repo-settings: introduce commitgraph.changedPathsVersion Jonathan Tan
2023-07-20 21:46   ` [PATCH v6 7/7] commit-graph: new filter ver. that fixes murmur3 Jonathan Tan
2023-07-25 20:52   ` [PATCH v6 0/7] Changed path filter hash fix and version bump Junio C Hamano
2023-07-26 20:39   ` Junio C Hamano
2023-07-27  0:17     ` Taylor Blau
2023-07-27  0:49       ` Junio C Hamano
2023-07-27 17:39         ` Jonathan Tan
2023-07-27 17:56           ` Taylor Blau
2023-07-27 20:53             ` Jonathan Tan
2023-08-01 18:08               ` Taylor Blau
2023-08-01 18:52                 ` Jonathan Tan
2023-08-03  0:01                 ` Taylor Blau
2023-08-03 13:18                   ` Derrick Stolee
2023-08-03 18:45                     ` Taylor Blau
2023-07-27 18:44         ` Junio C Hamano
2023-08-01 18:41 ` [PATCH v7 " Jonathan Tan
2023-08-01 18:41   ` [PATCH v7 1/7] gitformat-commit-graph: describe version 2 of BDAT Jonathan Tan
2023-08-01 18:41   ` [PATCH v7 2/7] t/helper/test-read-graph.c: extract `dump_graph_info()` Jonathan Tan
2023-08-01 18:41   ` [PATCH v7 3/7] bloom.h: make `load_bloom_filter_from_graph()` public Jonathan Tan
2023-08-01 18:41   ` [PATCH v7 4/7] t/helper/test-read-graph: implement `bloom-filters` mode Jonathan Tan
2023-08-01 18:41   ` [PATCH v7 5/7] t4216: test changed path filters with high bit paths Jonathan Tan
2023-08-01 18:41   ` [PATCH v7 6/7] repo-settings: introduce commitgraph.changedPathsVersion Jonathan Tan
2023-08-01 18:41   ` [PATCH v7 7/7] commit-graph: new filter ver. that fixes murmur3 Jonathan Tan
2023-08-01 18:44   ` [PATCH v7 0/7] Changed path filter hash fix and version bump Junio C Hamano
2023-08-01 20:58     ` Taylor Blau
2023-08-01 21:07       ` Junio C Hamano

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