Subject: Re: [PATCH v5 2/3] reftable/stack: add env to disable autocompaction

From: Patrick Steinhardt <[email-masked]>
Date: Mon, 8 Apr 2024 08:12:43 +0200

On Thu, Apr 04, 2024 at 06:29:28PM +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_AUTOCOMPACTION` environment variable that, when set
> to false, disables autocompaction of reftables.
> 
> Signed-off-by: Justin Tobler <[email-masked]>
> ---
>  refs/reftable-backend.c    |  4 ++++
>  t/t0610-reftable-basics.sh | 21 +++++++++++++++++++++
>  2 files changed, 25 insertions(+)
> 
> diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
> index 0bed6d2ab48..6b6191f89dd 100644
> --- a/refs/reftable-backend.c
> +++ b/refs/reftable-backend.c
> @@ -18,6 +18,7 @@
>  #include "../reftable/reftable-merged.h"
>  #include "../setup.h"
>  #include "../strmap.h"
> +#include "parse.h"
>  #include "refs-internal.h"
>  
>  /*
> @@ -248,6 +249,9 @@ static struct ref_store *reftable_be_init(struct repository *repo,
>  	refs->write_options.hash_id = repo->hash_algo->format_id;
>  	refs->write_options.default_permissions = calc_shared_perm(0666 & ~mask);
>  
> +	if (!git_env_bool("GIT_TEST_REFTABLE_AUTOCOMPACTION", 1))
> +		refs->write_options.disable_auto_compact = 1;
> +

This could be simplified to:

    ```
    refs->write_options.disable_auto_compact =
            !git_env_bool("GIT_TEST_REFTABLE_AUTOCOMPACTION", 1);
    ```

Patrick

>  	/*
>  	 * Set up the main reftable stack that is hosted in GIT_COMMON_DIR.
>  	 * This stack contains both the shared and the main worktree refs.
> diff --git a/t/t0610-reftable-basics.sh b/t/t0610-reftable-basics.sh
> index 931d888bbbc..c9e10b34684 100755
> --- a/t/t0610-reftable-basics.sh
> +++ b/t/t0610-reftable-basics.sh
> @@ -299,6 +299,27 @@ test_expect_success 'ref transaction: writes cause auto-compaction' '
>  	test_line_count = 1 repo/.git/reftable/tables.list
>  '
>  
> +test_expect_success 'ref transaction: env var disables compaction' '
> +	test_when_finished "rm -rf repo" &&
> +
> +	git init repo &&
> +	test_commit -C repo A &&
> +
> +	start=$(wc -l <repo/.git/reftable/tables.list) &&
> +	iterations=5 &&
> +	expected=$((start + iterations)) &&
> +
> +	for i in $(test_seq $iterations)
> +	do
> +		GIT_TEST_REFTABLE_AUTOCOMPACTION=false \
> +		git -C repo update-ref branch-$i HEAD || return 1
> +	done &&
> +	test_line_count = $expected repo/.git/reftable/tables.list &&
> +
> +	git -C repo update-ref foo HEAD &&
> +	test_line_count -lt $expected repo/.git/reftable/tables.list
> +'
> +
>  check_fsync_events () {
>  	local trace="$1" &&
>  	shift &&
> -- 
> gitgitgadget
>