Subject: Re: [PATCH 5/8] clone: set fetch.bundleURI if appropriate

From: Victoria Dye <[email-masked]>
Date: Thu, 19 Jan 2023 11:42:53 -0800

Derrick Stolee via GitGitGadget wrote:
> diff --git a/Documentation/config/fetch.txt b/Documentation/config/fetch.txt
> index cd65d236b43..4f796218aab 100644
> --- a/Documentation/config/fetch.txt
> +++ b/Documentation/config/fetch.txt
> @@ -96,3 +96,11 @@ fetch.writeCommitGraph::
>  	merge and the write may take longer. Having an updated commit-graph
>  	file helps performance of many Git commands, including `git merge-base`,
>  	`git push -f`, and `git log --graph`. Defaults to false.
> +
> +fetch.bundleURI::
> +	This value stores a URI for fetching Git object data from a bundle URI
> +	before performing an incremental fetch from the origin Git server. If
> +	the value is `<uri>` then running `git fetch <args>` is equivalent to
> +	first running `git fetch --bundle-uri=<uri>` immediately before
> +	`git fetch <args>`. See details of the `--bundle-uri` option in
> +	linkgit:git-fetch[1].

Since it's not mentioned from this or any other user-facing documentation
(AFAICT), could you note that this value is set automatically by 'git clone'
iff '--bundle-uri' is specified *and* 'bundle.heuristic' is set for the
initially downloaded bundle list?

It would also be nice to make note of that behavior in the documentation of
the '--bundle-uri' option in 'Documentation/git-clone.txt', since command
documentation in general seems to be more popular/visible to users than
config docs.

> diff --git a/builtin/clone.c b/builtin/clone.c
> index 5453ba5277f..5370617664d 100644
> --- a/builtin/clone.c
> +++ b/builtin/clone.c
> @@ -1248,12 +1248,16 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
>  	 * data from the --bundle-uri option.
>  	 */
>  	if (bundle_uri) {
> +		int has_heuristic = 0;
> +
>  		/* At this point, we need the_repository to match the cloned repo. */
>  		if (repo_init(the_repository, git_dir, work_tree))
>  			warning(_("failed to initialize the repo, skipping bundle URI"));
> -		else if (fetch_bundle_uri(the_repository, bundle_uri))
> +		else if (fetch_bundle_uri(the_repository, bundle_uri, &has_heuristic))
>  			warning(_("failed to fetch objects from bundle URI '%s'"),
>  				bundle_uri);
> +		else if (has_heuristic)
> +			git_config_set_gently("fetch.bundleuri", bundle_uri);

If the heuristic is anything other than "none", this config value is set in
the repository-scoped config file. Makes sense!

>  	}
>  
>  	strvec_push(&transport_ls_refs_options.ref_prefixes, "HEAD");
> diff --git a/bundle-uri.c b/bundle-uri.c
> index b30c85ba6f2..1dbbbb980eb 100644
> --- a/bundle-uri.c
> +++ b/bundle-uri.c
> @@ -594,9 +594,10 @@ static int fetch_bundle_list_in_config_format(struct repository *r,
>  	 * it advertises are expected to be bundles, not nested lists.
>  	 * We can drop 'global_list' and 'depth'.
>  	 */
> -	if (list_from_bundle.heuristic == BUNDLE_HEURISTIC_CREATIONTOKEN)
> +	if (list_from_bundle.heuristic == BUNDLE_HEURISTIC_CREATIONTOKEN) {
>  		result = fetch_bundles_by_token(r, &list_from_bundle);
> -	else if ((result = download_bundle_list(r, &list_from_bundle,
> +		global_list->heuristic = BUNDLE_HEURISTIC_CREATIONTOKEN;

If the 'heuristic' field already existed and was being used to apply
bundles, why wasn't 'global_list->heuristic' already being set? Before this
patch, was the 'global_list->heuristic' field not accurately reflecting the
heuristic type of a given bundle list? 

If so, I think it'd make sense to move this section to patch 4 [1], since
that's when the heuristic is first applied to the bundle list.

[1] https://lore.kernel.org/git/57c0[email-masked]/

> diff --git a/t/t5558-clone-bundle-uri.sh b/t/t5558-clone-bundle-uri.sh
> index d7461ec907e..8ff560425ee 100755
> --- a/t/t5558-clone-bundle-uri.sh
> +++ b/t/t5558-clone-bundle-uri.sh
> @@ -435,6 +435,39 @@ test_expect_success 'clone bundle list (http, creationToken)' '
>  	test_bundle_downloaded bundle-2.bundle trace-clone.txt
>  '
>  
> +test_expect_success 'http clone with bundle.heuristic creates fetch.bundleURI' '
> +	test_when_finished rm -rf fetch-http-4 trace*.txt &&
> +
> +	cat >"$HTTPD_DOCUMENT_ROOT_PATH/bundle-list" <<-EOF &&
> +	[bundle]
> +		version = 1
> +		mode = all
> +		heuristic = creationToken
> +
> +	[bundle "bundle-1"]
> +		uri = bundle-1.bundle
> +		creationToken = 1
> +	EOF
> +
> +	GIT_TRACE2_EVENT="$(pwd)/trace-clone.txt" \
> +	git clone --single-branch --branch=base \
> +		--bundle-uri="$HTTPD_URL/bundle-list" \
> +		"$HTTPD_URL/smart/fetch.git" fetch-http-4 &&
> +
> +	test_cmp_config -C fetch-http-4 "$HTTPD_URL/bundle-list" fetch.bundleuri &&
> +
> +	# The clone should copy two files: the list and bundle-1.
> +	test_bundle_downloaded bundle-list trace-clone.txt &&
> +	test_bundle_downloaded bundle-1.bundle trace-clone.txt &&
> +
> +	# only received base ref from bundle-1
> +	git -C fetch-http-4 for-each-ref --format="%(refname)" "refs/bundles/*" >refs &&
> +	cat >expect <<-\EOF &&
> +	refs/bundles/base
> +	EOF
> +	test_cmp expect refs
> +'

This test looks good - it verifies the config update, bundle download, and
unbundle all work as intended.

> +
>  # Do not add tests here unless they use the HTTP server, as they will
>  # not run unless the HTTP dependencies exist.
>