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Re: [PATCH 2/2] fetch: no redundant error message for atomic fetch

From
Patrick Steinhardt <ps@pks.im>
Date
Oct 23, 2023, 08:27 UTC
Message-ID
<ZTYue-3gAS1aGXNa@tanuki>
In-Reply-To
<ced46baeb1c18b416b4b4cc947f498bea2910b1b.1697725898.git.zhiyou.jx@alibaba-inc.com>
On Thu, Oct 19, 2023 at 10:34:33PM +0800, Jiang Xin wrote:
Show 34 quoted lines
> From: Jiang Xin <zhiyou.jx@alibaba-inc.com>
> 
> If an error occurs during an atomic fetch, a redundant error message
> will appear at the end of do_fetch(). It was introduced in b3a804663c
> (fetch: make `--atomic` flag cover backfilling of tags, 2022-02-17).
> 
> Instead of displaying the error message unconditionally, the final error
> output should follow the pattern in update-ref.c and files-backend.c as
> follows:
> 
>     if (ref_transaction_abort(transaction, &error))
>         error("abort: %s", error.buf);
> 
> This will fix the test case "fetch porcelain output (atomic)" in t5574.
> 
> Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
> ---
>  builtin/fetch.c         | 4 +---
>  t/t5574-fetch-output.sh | 2 +-
>  2 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/builtin/fetch.c b/builtin/fetch.c
> index fd134ba74d..01a573cf8d 100644
> --- a/builtin/fetch.c
> +++ b/builtin/fetch.c
> @@ -1775,10 +1775,8 @@ static int do_fetch(struct transport *transport,
>  	}
>  
>  cleanup:
> -	if (retcode && transaction) {
> -		ref_transaction_abort(transaction, &err);
> +	if (retcode && transaction && ref_transaction_abort(transaction, &err))
>  		error("%s", err.buf);
> -	}

Right. We already call `error()` in all cases where `err` was populated before we `goto cleanup;`, so calling it unconditionally a second time here is wrong.

That being said, `ref_transaction_abort()` will end up calling the respective backend's implementation of `transaction_abort`, and for the files backend it actually ignores `err` completely. So if the abort fails, we would still end up calling `error()` with an empty string. Furthermore, it can happen that `transaction_commit` fails, writes to the buffer and then prints the error. If the abort now fails as well, we would end up printing the error message twice.

I wonder whether we should fix this by unifying all calls to `error()` to only happen in the cleanup block, and only iff the buffer length is non-zero?

Patrick
Show 18 quoted lines
>  	display_state_release(&display_state);
>  	close_fetch_head(&fetch_head);
> diff --git a/t/t5574-fetch-output.sh b/t/t5574-fetch-output.sh
> index 1397101629..3c72fc693f 100755
> --- a/t/t5574-fetch-output.sh
> +++ b/t/t5574-fetch-output.sh
> @@ -97,7 +97,7 @@ do
>  		opt=
>  		;;
>  	esac
> -	test_expect_failure "fetch porcelain output ${opt:+(atomic)}" '
> +	test_expect_success "fetch porcelain output ${opt:+(atomic)}" '
>  		test_when_finished "rm -rf porcelain" &&
>  
>  		# Clone and pre-seed the repositories. We fetch references into two
> -- 
> 2.42.0.411.g813d9a9188
> 
Previous: Jiang XinNext: Jiang Xin
Message 3 of 19 in “t5574: test porcelain output of atomic fetch”
  1. 1/2 t5574: test porcelain output of atomic fetchJiang Xin, Oct 19, 2023
  2. 2/2 fetch: no redundant error message for atomic fetchJiang Xin, Oct 19, 2023
  3. Patrick SteinhardtOct 23, 2023
  4. Jiang XinOct 23, 2023
  5. Patrick SteinhardtOct 23, 2023
  6. Jiang XinOct 23, 2023
  7. Patrick SteinhardtOct 25, 2023
  8. Junio C HamanoOct 24, 2023
  9. 0/2 jx/fetch-atomic-error-message-fixJiang Xin, Dec 14, 2023
  10. 1/2 t5574: test porcelain output of atomic fetchJiang Xin, Dec 14, 2023
  11. Patrick SteinhardtDec 15, 2023
  12. Jiang XinDec 15, 2023
  13. Junio C HamanoDec 15, 2023
  14. 2/2 fetch: no redundant error message for atomic fetchJiang Xin, Dec 14, 2023
  15. Patrick SteinhardtDec 15, 2023
  16. 0/2 fix fetch atomic error messageJiang Xin, Dec 17, 2023
  17. 1/2 t5574: test porcelain output of atomic fetchJiang Xin, Dec 17, 2023
  18. 2/2 fetch: no redundant error message for atomic fetchJiang Xin, Dec 17, 2023
  19. Patrick SteinhardtDec 18, 2023

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