Subject: Re: [PATCH v3 1/3] reftable/stack: add env to disable autocompaction

From: Patrick Steinhardt <[email-masked]>
Date: Tue, 2 Apr 2024 09:23:45 +0200

On Fri, Mar 29, 2024 at 04:16:47AM +0000, Justin Tobler via GitGitGadget wrote:
> From: Justin Tobler <[email-masked]>
> 
> In future tests it will be neccesary to create repositories with a set
> number of tables. To make this easier, introduce the
> `GIT_TEST_REFTABLE_NO_AUTOCOMPACTION` environment variable that, when
> set, disables autocompaction of reftables.
> 
> Signed-off-by: Justin Tobler <[email-masked]>
> ---
>  reftable/stack.c           |  2 +-
>  reftable/system.h          |  1 +
>  t/t0610-reftable-basics.sh | 15 +++++++++++++++
>  3 files changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/reftable/stack.c b/reftable/stack.c
> index 1ecf1b9751c..07262beaaf7 100644
> --- a/reftable/stack.c
> +++ b/reftable/stack.c
> @@ -681,7 +681,7 @@ int reftable_addition_commit(struct reftable_addition *add)
>  	if (err)
>  		goto done;
>  
> -	if (!add->stack->disable_auto_compact)
> +	if (!add->stack->disable_auto_compact && !git_env_bool("GIT_TEST_REFTABLE_NO_AUTOCOMPACTION", 0))
>  		err = reftable_stack_auto_compact(add->stack);

The double-negation in `GIT_TEST_REFTABLE_NO_AUTOCOMPACTION=false` may be
somewhat hard to parse. Should we rename this to
`GIT_TEST_REFTABLE_AUTO_COMPACTION` with a default value of `1`?

Patrick

>  done:
> diff --git a/reftable/system.h b/reftable/system.h
> index 5d8b6dede50..05b7c8554af 100644
> --- a/reftable/system.h
> +++ b/reftable/system.h
> @@ -17,6 +17,7 @@ license that can be found in the LICENSE file or at
>  #include "tempfile.h"
>  #include "hash-ll.h" /* hash ID, sizes.*/
>  #include "dir.h" /* remove_dir_recursively, for tests.*/
> +#include "parse.h"
>  
>  int hash_size(uint32_t id);
>  
> diff --git a/t/t0610-reftable-basics.sh b/t/t0610-reftable-basics.sh
> index 686781192eb..434044078ed 100755
> --- a/t/t0610-reftable-basics.sh
> +++ b/t/t0610-reftable-basics.sh
> @@ -299,6 +299,21 @@ test_expect_success 'ref transaction: writes cause auto-compaction' '
>  	test_line_count = 1 repo/.git/reftable/tables.list
>  '
>  
> +test_expect_success 'ref transaction: environment variable disables auto-compaction' '
> +	test_when_finished "rm -rf repo" &&
> +
> +	git init repo &&
> +	test_commit -C repo A &&
> +	for i in $(test_seq 20)
> +	do
> +		GIT_TEST_REFTABLE_NO_AUTOCOMPACTION=true git -C repo update-ref branch-$i HEAD || return 1
> +	done &&
> +	test_line_count = 23 repo/.git/reftable/tables.list &&
> +
> +	git -C repo update-ref foo HEAD &&
> +	test_line_count = 1 repo/.git/reftable/tables.list
> +'
> +
>  check_fsync_events () {
>  	local trace="$1" &&
>  	shift &&
> -- 
> gitgitgadget
>