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Re: [PATCH v3 18/20] commit-graph: add '--reachable' option

From
Derrick Stolee <stolee@gmail.com>
Date
Jun 4, 2018, 12:44 UTC
Message-ID
<4dccf288-ccf1-6819-4112-00432db1ddc6@gmail.com>
In-Reply-To
<86k1rhrt1u.fsf@gmail.com>
On 6/2/2018 1:34 PM, Jakub Narebski wrote:
Show 102 quoted lines
> Derrick Stolee <dstolee@microsoft.com> writes:
>
>> When writing commit-graph files, it can be convenient to ask for all
>> reachable commits (starting at the ref set) in the resulting file. This
>> is particularly helpful when writing to stdin is complicated, such as a
>> future integration with 'git gc' which will call
>> write_commit_graph_reachable() after performing cleanup of the object
>> database.
> Nice.
>
> The last sentence of the commit message is a bit long, though, in my
> opinion.
>
>> Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
>> ---
>>   Documentation/git-commit-graph.txt |  8 ++++++--
>>   builtin/commit-graph.c             | 16 ++++++++++++----
>>   commit-graph.c                     | 32 ++++++++++++++++++++++++++++++++
>>   commit-graph.h                     |  1 +
>>   t/t5318-commit-graph.sh            | 10 ++++++++++
>>   5 files changed, 61 insertions(+), 6 deletions(-)
>>
>> diff --git a/Documentation/git-commit-graph.txt b/Documentation/git-commit-graph.txt
>> index a222cfab08..dececb79d7 100644
>> --- a/Documentation/git-commit-graph.txt
>> +++ b/Documentation/git-commit-graph.txt
>> @@ -38,12 +38,16 @@ Write a commit graph file based on the commits found in packfiles.
>>   +
>>   With the `--stdin-packs` option, generate the new commit graph by
>>   walking objects only in the specified pack-indexes. (Cannot be combined
>> -with --stdin-commits.)
>> +with `--stdin-commits` or `--reachable`.)
>>   +
>>   With the `--stdin-commits` option, generate the new commit graph by
>>   walking commits starting at the commits specified in stdin as a list
>>   of OIDs in hex, one OID per line. (Cannot be combined with
>> ---stdin-packs.)
>> +`--stdin-packs` or `--reachable`.)
>> ++
>> +With the `--reachable` option, generate the new commit graph by walking
>> +commits starting at all refs. (Cannot be combined with `--stdin-commits`
>> +or `--stdin-packs`.)
> All right (though I wonder a bit about the restriction).
>
> I think it might be a good idea to describe all of this in the usage
> string for the 'git commit-graph write', instead of using '<options>'
> placeholder, that is instead of current:
>
>    'git commit-graph write' <options> [--object-dir <dir>]
>
> use
>
>    'git commit-graph write' [--stdin-commits | --stdin-packs | --reachable]
>                             [--append] [--object-dir <dir>]
>
> or something like that.
>
>>   +
>>   With the `--append` option, include all commits that are present in the
>>   existing commit-graph file.
>> diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
>> index 0433dd6e20..20ce6437ae 100644
>> --- a/builtin/commit-graph.c
>> +++ b/builtin/commit-graph.c
>> @@ -9,7 +9,7 @@ static char const * const builtin_commit_graph_usage[] = {
>>   	N_("git commit-graph [--object-dir <objdir>]"),
>>   	N_("git commit-graph read [--object-dir <objdir>]"),
>>   	N_("git commit-graph verify [--object-dir <objdir>]"),
>> -	N_("git commit-graph write [--object-dir <objdir>] [--append] [--stdin-packs|--stdin-commits]"),
>> +	N_("git commit-graph write [--object-dir <objdir>] [--append] [--reachable|--stdin-packs|--stdin-commits]"),
> All right, very straightforward.  I guess they are put in [almost]
> alphabetical order, or is there some other reasoning behind the ordering
> used (which is different from the one in the manpage)?
>
>>   	NULL
>>   };
>>   
>> @@ -24,12 +24,13 @@ static const char * const builtin_commit_graph_read_usage[] = {
>>   };
>>   
>>   static const char * const builtin_commit_graph_write_usage[] = {
>> -	N_("git commit-graph write [--object-dir <objdir>] [--append] [--stdin-packs|--stdin-commits]"),
>> +	N_("git commit-graph write [--object-dir <objdir>] [--append] [--reachable|--stdin-packs|--stdin-commits]"),
> The same.
>
>>   	NULL
>>   };
>>   
>>   static struct opts_commit_graph {
>>   	const char *obj_dir;
>> +	int reachable;
>>   	int stdin_packs;
>>   	int stdin_commits;
>>   	int append;
>> @@ -130,6 +131,8 @@ static int graph_write(int argc, const char **argv)
>>   		OPT_STRING(0, "object-dir", &opts.obj_dir,
>>   			N_("dir"),
>>   			N_("The object directory to store the graph")),
>> +		OPT_BOOL(0, "reachable", &opts.reachable,
>> +			N_("start walk at all refs")),
> Errr... does '--no-reachable' makes sense?  Because if I am right
> currently it is supported, isn't it.

True, but the same holds for many arguments in the codebase. Just looking at 'git apply' as a sample, it uses OPT_BOOL for "numstat", "summary", "check", "index", "cached", "apply", and "no-add" (so "--no-no-add" works?). I think accepting "--no-reachable" is fine, since it will set opts.reachable = 0 and we will not use the reachable option.

Show 60 quoted lines
>
>>   		OPT_BOOL(0, "stdin-packs", &opts.stdin_packs,
>>   			N_("scan pack-indexes listed by stdin for commits")),
>>   		OPT_BOOL(0, "stdin-commits", &opts.stdin_commits,
>> @@ -143,11 +146,16 @@ static int graph_write(int argc, const char **argv)
>>   			     builtin_commit_graph_write_options,
>>   			     builtin_commit_graph_write_usage, 0);
>>   
>> -	if (opts.stdin_packs && opts.stdin_commits)
>> -		die(_("cannot use both --stdin-commits and --stdin-packs"));
>> +	if (opts.reachable + opts.stdin_packs + opts.stdin_commits > 1)
> Nice trick.
>
>> +		die(_("use at most one of --reachable, --stdin-commits, or --stdin-packs"));
> It is a pity that parseopt API does not have direct support for mutually
> exclusive groups of boolean options, like ArgumentParser.add_mutually_exclusive_group()
> in Python's argparse.
>
> Still, you need to use what it is there.
>
>>   	if (!opts.obj_dir)
>>   		opts.obj_dir = get_object_directory();
>>   
>> +	if (opts.reachable) {
>> +		write_commit_graph_reachable(opts.obj_dir, opts.append);
>> +		return 0;
>> +	}
> Just using the option.
>
>> +
>>   	if (opts.stdin_packs || opts.stdin_commits) {
>>   		struct strbuf buf = STRBUF_INIT;
>>   		lines_nr = 0;
>> diff --git a/commit-graph.c b/commit-graph.c
>> index a33600c584..057d734926 100644
>> --- a/commit-graph.c
>> +++ b/commit-graph.c
>> @@ -6,6 +6,7 @@
>>   #include "packfile.h"
>>   #include "commit.h"
>>   #include "object.h"
>> +#include "refs.h"
>>   #include "revision.h"
>>   #include "sha1-lookup.h"
>>   #include "commit-graph.h"
>> @@ -651,6 +652,37 @@ static void compute_generation_numbers(struct packed_commit_list* commits)
>>   	}
>>   }
>>   
>> +struct hex_list {
>> +	char **hex_strs;
>> +	int hex_nr;
>> +	int hex_alloc;
>> +};
> Is this what git-for-each-ref / git-branch / git-tag uses?
>
> Would it be possible to use for example string-list API (documented in
> string-list.h) instead?  Anyway, it looks like the use of allocation
> growing API is simple enough... though perhaps it could be made simpler
> by noticing that all strings have the same width.

I should use the string-list API for more than just this list of strings. I'll add a new commit that replaces the `const char **` parameters from write_commit_graph(), then this commit becomes much simpler.

Show 75 quoted lines
>
>> +
>> +static int add_ref_to_list(const char *refname,
>> +			   const struct object_id *oid,
>> +			   int flags, void *cb_data)
>> +{
>> +	struct hex_list *list = (struct hex_list*)cb_data;
>> +
>> +	ALLOC_GROW(list->hex_strs, list->hex_nr + 1, list->hex_alloc);
>> +	list->hex_strs[list->hex_nr] = xcalloc(GIT_MAX_HEXSZ + 1, 1);
>> +	strcpy(list->hex_strs[list->hex_nr], oid_to_hex(oid));
> Wouldn't it be better to use strdup or xstrdup instead of
> xcalloc+strcpy?
>
>> +	list->hex_nr++;
>> +	return 0;
>> +}
>> +
>> +void write_commit_graph_reachable(const char *obj_dir, int append)
>> +{
>> +	struct hex_list list;
>> +	list.hex_nr = 0;
>> +	list.hex_alloc = 128;
>> +	ALLOC_ARRAY(list.hex_strs, list.hex_alloc);
>> +
>> +	for_each_ref(add_ref_to_list, &list);
>> +
>> +	write_commit_graph(obj_dir, NULL, 0, (const char **)list.hex_strs, list.hex_nr, append);
> Where do we free the allocated data and allocated strings?  If they are
> cleaned by process exit, perhaps they need to be UNLEAK-ed?
>
>> +}
>> +
>>   void write_commit_graph(const char *obj_dir,
>>   			const char **pack_indexes,
>>   			int nr_packs,
>> diff --git a/commit-graph.h b/commit-graph.h
>> index 71a39c5a57..9a06a5f188 100644
>> --- a/commit-graph.h
>> +++ b/commit-graph.h
>> @@ -46,6 +46,7 @@ struct commit_graph {
>>   
>>   struct commit_graph *load_commit_graph_one(const char *graph_file);
>>   
>> +void write_commit_graph_reachable(const char *obj_dir, int append);
>>   void write_commit_graph(const char *obj_dir,
>>   			const char **pack_indexes,
>>   			int nr_packs,
>> diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
>> index 4941937163..a659620332 100755
>> --- a/t/t5318-commit-graph.sh
>> +++ b/t/t5318-commit-graph.sh
>> @@ -205,6 +205,16 @@ test_expect_success 'build graph from commits with append' '
>>   graph_git_behavior 'append graph, commit 8 vs merge 1' full commits/8 merge/1
>>   graph_git_behavior 'append graph, commit 8 vs merge 2' full commits/8 merge/2
>>   
>> +test_expect_success 'build graph using --reachable' '
>> +	cd "$TRASH_DIRECTORY/full" &&
>> +	git commit-graph write --reachable &&
>> +	test_path_is_file $objdir/info/commit-graph &&
>> +	graph_read_expect "11" "large_edges"
>> +'
> All right, here we check that commit-graph has expected features (11
> commits, and large_edges optional chunk).
>
> Perhaps we could also check that different equivalent ways of creating
> serialized commit graph file produce byte-for-byte identical file?
>
>> +
>> +graph_git_behavior 'append graph, commit 8 vs merge 1' full commits/8 merge/1
>> +graph_git_behavior 'append graph, commit 8 vs merge 2' full commits/8 merge/2
> All right, this supposedly tests that behavior does not change whether
> we are using or we are not using the commit-graph feature... but I have
> just noticed that raph_git_two_modes() uses `git -c core.graph=true`;
> shouldn't it be `git -c core.commitGraph=true`?

WOW good catch. I've sent a patch to fix that immediately, as these tests are not doing what they should (verify the core.commitGraph setting does not change the output of the walk).

Show 5 quoted lines
>
>> +
>>   test_expect_success 'setup bare repo' '
>>   	cd "$TRASH_DIRECTORY" &&
>>   	git clone --bare --no-local full bare &&
Previous: Jakub NarebskiNext: Derrick Stolee
Message 141 of 149 in “Integrate commit-graph into 'fsck' and 'gc'”
  1. 00/12 Integrate commit-graph into 'fsck' and 'gc'Derrick Stolee, Apr 17, 2018
  2. 01/12 fixup! commit-graph: always load commit-graph informationDerrick Stolee, Apr 17, 2018
  3. 04/12 commit-graph: parse commit from chosen graphDerrick Stolee, Apr 17, 2018
  4. Jakub NarebskiApr 19, 2018
  5. 06/12 commit: force commit to parse from object databaseDerrick Stolee, Apr 17, 2018
  6. Jakub NarebskiApr 20, 2018
  7. 07/12 commit-graph: load a root tree from specific graphDerrick Stolee, Apr 17, 2018
  8. Jakub NarebskiApr 20, 2018
  9. 10/12 commit-graph: add '--reachable' optionDerrick Stolee, Apr 17, 2018
  10. Jakub NarebskiApr 20, 2018
  11. 12/12 commit-graph: update design documentDerrick Stolee, Apr 17, 2018
  12. Jakub NarebskiApr 20, 2018
  13. 11/12 gc: automatically write commit-graph filesDerrick Stolee, Apr 17, 2018
  14. Jakub NarebskiApr 20, 2018
  15. Ævar Arnfjörð BjarmasonApr 20, 2018
  16. 09/12 fsck: check commit-graphDerrick Stolee, Apr 17, 2018
  17. Jakub NarebskiApr 20, 2018
  18. 08/12 commit-graph: verify commit contents against odbDerrick Stolee, Apr 17, 2018
  19. Jakub NarebskiApr 20, 2018
  20. 02/12 commit-graph: add 'check' subcommandDerrick Stolee, Apr 17, 2018
  21. Jakub NarebskiApr 19, 2018
  22. 03/12 commit-graph: check file header informationDerrick Stolee, Apr 17, 2018
  23. Jakub NarebskiApr 19, 2018
  24. 05/12 commit-graph: check fanout and lookup tableDerrick Stolee, Apr 17, 2018
  25. Jakub NarebskiApr 20, 2018
  26. Derrick StoleeApr 17, 2018
  27. 00/12 Integrate commit-graph into fsck, gc, and fetchDerrick Stolee, May 10, 2018
  28. 01/12 commit-graph: add 'verify' subcommandDerrick Stolee, May 10, 2018
  29. Martin ÅgrenMay 10, 2018
  30. 02/12 commit-graph: verify file header informationDerrick Stolee, May 10, 2018
  31. Martin ÅgrenMay 10, 2018
  32. 04/12 commit-graph: verify fanout and lookup tableDerrick Stolee, May 10, 2018
  33. Martin ÅgrenMay 10, 2018
  34. Derrick StoleeMay 11, 2018
  35. 06/12 commit-graph: load a root tree from specific graphDerrick Stolee, May 10, 2018
  36. 08/12 fsck: verify commit-graphDerrick Stolee, May 10, 2018
  37. 12/12 commit-graph: update design documentDerrick Stolee, May 10, 2018
  38. 11/12 fetch: compute commit-graph by defaultDerrick Stolee, May 10, 2018
  39. 07/12 commit-graph: verify commit contents against odbDerrick Stolee, May 10, 2018
  40. 09/12 commit-graph: add '--reachable' optionDerrick Stolee, May 10, 2018
  41. 10/12 gc: automatically write commit-graph filesDerrick Stolee, May 10, 2018
  42. 05/12 commit: force commit to parse from object databaseDerrick Stolee, May 10, 2018
  43. 03/12 commit-graph: parse commit from chosen graphDerrick Stolee, May 10, 2018
  44. Martin ÅgrenMay 10, 2018
  45. Stefan BellerMay 10, 2018
  46. Derrick StoleeMay 11, 2018
  47. Martin ÅgrenMay 11, 2018
  48. Ævar Arnfjörð BjarmasonMay 10, 2018
  49. Derrick StoleeMay 11, 2018
  50. 00/12 Integrate commit-graph into fsck and gcDerrick Stolee, May 11, 2018
  51. 02/12 commit-graph: verify file header informationDerrick Stolee, May 11, 2018
  52. Martin ÅgrenMay 12, 2018
  53. Derrick StoleeMay 14, 2018
  54. Jakub NarebskiMay 20, 2018
  55. 01/12 commit-graph: add 'verify' subcommandDerrick Stolee, May 11, 2018
  56. Martin ÅgrenMay 12, 2018
  57. Derrick StoleeMay 14, 2018
  58. Jakub NarebskiMay 20, 2018
  59. 03/12 commit-graph: test that 'verify' finds corruptionDerrick Stolee, May 11, 2018
  60. Martin ÅgrenMay 12, 2018
  61. Jakub NarebskiMay 21, 2018
  62. Derrick StoleeMay 24, 2018
  63. 04/12 commit-graph: parse commit from chosen graphDerrick Stolee, May 11, 2018
  64. Martin ÅgrenMay 12, 2018
  65. 05/12 commit-graph: verify fanout and lookup tableDerrick Stolee, May 11, 2018
  66. 06/12 commit: force commit to parse from object databaseDerrick Stolee, May 11, 2018
  67. Martin ÅgrenMay 12, 2018
  68. 09/12 fsck: verify commit-graphDerrick Stolee, May 11, 2018
  69. Martin ÅgrenMay 17, 2018
  70. 11/12 gc: automatically write commit-graph filesDerrick Stolee, May 11, 2018
  71. Martin ÅgrenMay 17, 2018
  72. 12/12 commit-graph: update design documentDerrick Stolee, May 11, 2018
  73. 07/12 commit-graph: load a root tree from specific graphDerrick Stolee, May 11, 2018
  74. Martin ÅgrenMay 12, 2018
  75. 08/12 commit-graph: verify commit contents against odbDerrick Stolee, May 11, 2018
  76. Martin ÅgrenMay 12, 2018
  77. Derrick StoleeMay 14, 2018
  78. Martin ÅgrenMay 15, 2018
  79. 10/12 commit-graph: add '--reachable' optionDerrick Stolee, May 11, 2018
  80. Martin ÅgrenMay 17, 2018
  81. 00/20 Integrate commit-graph into 'fsck' and 'gc'Derrick Stolee, May 24, 2018
  82. 01/20 commit-graph: UNLEAK before die()Derrick Stolee, May 24, 2018
  83. Stefan BellerMay 24, 2018
  84. Derrick StoleeMay 25, 2018
  85. 04/20 commit: force commit to parse from object databaseDerrick Stolee, May 24, 2018
  86. Jakub NarebskiMay 27, 2018
  87. 03/20 commit-graph: parse commit from chosen graphDerrick Stolee, May 24, 2018
  88. Jakub NarebskiMay 27, 2018
  89. Derrick StoleeMay 29, 2018
  90. 06/20 commit-graph: add 'verify' subcommandDerrick Stolee, May 24, 2018
  91. Jakub NarebskiMay 27, 2018
  92. Derrick StoleeMay 30, 2018
  93. Jakub NarebskiJun 2, 2018
  94. Derrick StoleeJun 4, 2018
  95. 07/20 commit-graph: verify catches corrupt signatureDerrick Stolee, May 24, 2018
  96. Jakub NarebskiMay 28, 2018
  97. Derrick StoleeMay 29, 2018
  98. Jakub NarebskiJun 2, 2018
  99. 05/20 commit-graph: load a root tree from specific graphDerrick Stolee, May 24, 2018
  100. Jakub NarebskiMay 27, 2018
  101. 08/20 commit-graph: verify required chunks are presentDerrick Stolee, May 24, 2018
  102. Jakub NarebskiMay 28, 2018
  103. 02/20 commit-graph: fix GRAPH_MIN_SIZEDerrick Stolee, May 24, 2018
  104. Jakub NarebskiMay 26, 2018
  105. brian m. carlsonMay 26, 2018
  106. Jakub NarebskiJun 2, 2018
  107. 09/20 commit-graph: verify corrupt OID fanout and lookupDerrick Stolee, May 24, 2018
  108. Jakub NarebskiMay 30, 2018
  109. Derrick StoleeMay 30, 2018
  110. Duy NguyenJun 2, 2018
  111. Derrick StoleeJun 4, 2018
  112. Duy NguyenJun 4, 2018
  113. 10/20 commit-graph: verify objects existDerrick Stolee, May 24, 2018
  114. Jakub NarebskiMay 30, 2018
  115. Derrick StoleeMay 31, 2018
  116. 11/20 commit-graph: verify root tree OIDsDerrick Stolee, May 24, 2018
  117. Jakub NarebskiMay 30, 2018
  118. Derrick StoleeMay 31, 2018
  119. Jakub NarebskiJun 2, 2018
  120. 12/20 commit-graph: verify parent listDerrick Stolee, May 24, 2018
  121. Jakub NarebskiJun 1, 2018
  122. 14/20 commit-graph: verify commit dateDerrick Stolee, May 24, 2018
  123. Jakub NarebskiJun 2, 2018
  124. 16/20 commit-graph: verify contents match checksumDerrick Stolee, May 24, 2018
  125. SZEDER GáborMay 30, 2018
  126. Jakub NarebskiJun 2, 2018
  127. Derrick StoleeJun 4, 2018
  128. 19/20 gc: automatically write commit-graph filesDerrick Stolee, May 24, 2018
  129. Jakub NarebskiJun 2, 2018
  130. Derrick StoleeJun 4, 2018
  131. 20/20 commit-graph: update design documentDerrick Stolee, May 24, 2018
  132. Jakub NarebskiJun 2, 2018
  133. 17/20 fsck: verify commit-graphDerrick Stolee, May 24, 2018
  134. Jakub NarebskiJun 2, 2018
  135. Derrick StoleeJun 4, 2018
  136. 15/20 commit-graph: test for corrupted octopus edgeDerrick Stolee, May 24, 2018
  137. Jakub NarebskiJun 2, 2018
  138. Derrick StoleeJun 4, 2018
  139. 18/20 commit-graph: add '--reachable' optionDerrick Stolee, May 24, 2018
  140. Jakub NarebskiJun 2, 2018
  141. Derrick StoleeJun 4, 2018
  142. 13/20 commit-graph: verify generation numberDerrick Stolee, May 24, 2018
  143. Jakub NarebskiJun 2, 2018
  144. Derrick StoleeJun 4, 2018
  145. Ævar Arnfjörð BjarmasonMay 24, 2018
  146. Junio C HamanoMay 25, 2018
  147. Junio C HamanoMay 29, 2018
  148. Derrick StoleeMay 29, 2018
  149. Junio C HamanoMay 29, 2018

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