Subject: Re: [PATCH v2 3/4] bulk-checkin: require transaction for index_blob_bulk_checkin()

From: Junio C Hamano <[email-masked]>
Date: Fri, 22 Aug 2025 09:49:39 -0700

Justin Tobler <[email-masked]> writes:

>  /*
> - * This creates one packfile per large blob unless bulk-checkin
> - * machinery is "plugged".
> + * This writes the specified object to a packfile. Objects written here
> + * during the same transaction are written to the same packfile. The
> + * packfile is not flushed until the transaction is flushed. The caller
> + * is expected to ensure a valid transaction is setup for objects to be
> + * recorded to.
>   *
>   * This also bypasses the usual "convert-to-git" dance, and that is on
>   * purpose. We could write a streaming version of the converting
> diff --git a/object-file.c b/object-file.c
> index 1740aa2b2e3..bc15af42450 100644
> --- a/object-file.c
> +++ b/object-file.c
> @@ -1253,19 +1253,26 @@ int index_fd(struct index_state *istate, struct object_id *oid,
>  	 * Call xsize_t() only when needed to avoid potentially unnecessary
>  	 * die() for large files.
>  	 */
> -	if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(istate, path))
> +	if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(istate, path)) {
>  		ret = index_stream_convert_blob(istate, oid, fd, path, flags);
> -	else if (!S_ISREG(st->st_mode))
> +	} else if (!S_ISREG(st->st_mode)) {
>  		ret = index_pipe(istate, oid, fd, type, path, flags);
> -	else if ((st->st_size >= 0 && (size_t) st->st_size <= repo_settings_get_big_file_threshold(istate->repo)) ||
> -		 type != OBJ_BLOB ||
> -		 (path && would_convert_to_git(istate, path)))
> +	} else if ((st->st_size >= 0 &&
> +		    (size_t)st->st_size <= repo_settings_get_big_file_threshold(istate->repo)) ||
> +		   type != OBJ_BLOB ||
> +		   (path && would_convert_to_git(istate, path))) {
>  		ret = index_core(istate, oid, fd, xsize_t(st->st_size),
>  				 type, path, flags);
> -	else
> -		ret = index_blob_bulk_checkin(the_repository->objects->transaction,
> +	} else {
> +		struct odb_transaction *transaction;
> +
> +		transaction = begin_odb_transaction(the_repository->objects);
> +		ret = index_blob_bulk_checkin(transaction,
>  					      oid, fd, xsize_t(st->st_size),
>  					      path, flags);
> +		end_odb_transaction(transaction);
> +	}

Interesting.  If the caller does the odb transaction management
itself by calling begin/end before calling this function and fed two
or more large objects, the original code did the right thing with
.nesting set to 1.  In the new code, it still does the right thing
even during the call to index_blob_bulk_checkin we raise .nesting by
one, because the all non-zero .nesting values mean the same thing to
the machinery, thanks to lazy initialization of the .objdir.

So, isn't the comment above the function now less accurate than
before?  The caller of this function does not have to do anything
and we do not expect the caller to "ensure a valid transaction" at
all, no?

Thanks.