Re: [PATCH v4 1/4] sparse index: enable only for git repos

[Lessley Dennington <lessleydennington@gmail.com>]

On 11/23/21 3:39 PM, Junio C Hamano wrote:
> "Lessley Dennington via GitGitGadget" <gitgitgadget@gmail.com>
> writes:
> 
>> From: Lessley Dennington <lessleydennington@gmail.com>
>>
>> Check whether git dir exists before adding any repo settings. If it
>> does not exist, BUG with the message that one cannot add settings for an
>> uninitialized repository. If it does exist, proceed with adding repo
>> settings.
>>
>> Additionally, ensure the above BUG is not triggered when users pass the -h
>> flag by adding a check for the repository to the checkout and pack-objects
>> builtins.
>>
>> Finally, ensure the above BUG is not triggered for commit-graph by
>> returning early if the git directory does not exist.
>>
>> Signed-off-by: Lessley Dennington <lessleydennington@gmail.com>
>> ---
>>   builtin/checkout.c     | 6 ++++--
>>   builtin/pack-objects.c | 9 ++++++---
>>   commit-graph.c         | 5 ++++-
>>   repo-settings.c        | 3 +++
>>   4 files changed, 17 insertions(+), 6 deletions(-)
>>
>> diff --git a/builtin/checkout.c b/builtin/checkout.c
>> index 8c69dcdf72a..31632b07888 100644
>> --- a/builtin/checkout.c
>> +++ b/builtin/checkout.c
>> @@ -1588,8 +1588,10 @@ static int checkout_main(int argc, const char **argv, const char *prefix,
>>   
>>   	git_config(git_checkout_config, opts);
>>   
>> -	prepare_repo_settings(the_repository);
>> -	the_repository->settings.command_requires_full_index = 0;
>> +	if (startup_info->have_repository) {
>> +		prepare_repo_settings(the_repository);
>> +		the_repository->settings.command_requires_full_index = 0;
>> +	}
> 
> I am kind-a surprised if the control reaches this deep if you are
> not in a repository.  In git.c::commands[] list, all three primary
> entry points that call checkout_main(), namely, cmd_checkout(),
> cmd_restore(), and cmd_switch(), are marked with RUN_SETUP bit,
> which makes us call setup_git_directory() even before we call the
> cmd_X() function.  And setup_git_directory() dies with "not a git
> repository (or any of the parent directories)" outside a repository.
> 
> So, how can startup_info->have_repository bit be false if the
> control flow reaches here?  Or am I grossly misunderstanding what
> you are trying to do?
> 
This was in reaction to the t0012-help.sh tests failing with the
new BUG in prepare_repo_settings. However, Elijah pointed out
that it's a better idea to move prepare_repo_settings farther
down (after parse_options) instead. So I will be issuing that
change as part of v5.
>> diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
>> index 1a3dd445f83..45dc2258dc7 100644
>> --- a/builtin/pack-objects.c
>> +++ b/builtin/pack-objects.c
>> @@ -3976,9 +3976,12 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
>>   	read_replace_refs = 0;
> 
> Ditto wrt RUN_SETUP.
> 
Updating with the same change as checkout for v5.
>> diff --git a/commit-graph.c b/commit-graph.c
>> index 2706683acfe..265c010122e 100644
>> --- a/commit-graph.c
>> +++ b/commit-graph.c
>> @@ -632,10 +632,13 @@ static int prepare_commit_graph(struct repository *r)
>>   	struct object_directory *odb;
>>   	/*
>> +	 * Early return if there is no git dir or if the commit graph is
>> +	 * disabled.
>> +	 *
>>   	 * This must come before the "already attempted?" check below, because
>>   	 * we want to disable even an already-loaded graph file.
>>   	 */
>> -	if (r->commit_graph_disabled)
>> +	if (!r->gitdir || r->commit_graph_disabled)
>>   		return 0;
> 
> I haven't followed the control flow, but this one probably is a good
> addition (in other words, unlike cmd_pack_objects(), I cannot convince
> myself that r->gitdir will never be NULL here).
> 
>> diff --git a/repo-settings.c b/repo-settings.c
>> index b93e91a212e..00ca5571a1a 100644
>> --- a/repo-settings.c
>> +++ b/repo-settings.c
>> @@ -17,6 +17,9 @@ void prepare_repo_settings(struct repository *r)
>>   	char *strval;
>>   	int manyfiles;
>>   
>> +	if (!r->gitdir)
>> +		BUG("Cannot add settings for uninitialized repository");
>> +
> 
> This is a very good idea.  If I recall correctly, I think I reviewed
> a bugfix patch that would have been simplified if we had this check
> here.
>Lessley