clone: set fetch.bundleURI if bundle.forFetch is advertised

TODO: change forFetch local to a 'flags' value.

NEEDSWORK: we are downloading too many bundles.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>

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].

builtin/clone.c

@@ -1245,11 +1245,15 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	 * data from the --bundle-uri option.
 	 */
 	if (bundle_uri) {
+		enum bundle_list_flags flags = 0;
+
 		/* At this point, we need the_repository to match the cloned repo. */
 		repo_init(the_repository, git_dir, work_tree);
-		if (fetch_bundle_uri(the_repository, bundle_uri))
+		if (fetch_bundle_uri(the_repository, bundle_uri, &flags))
 			warning(_("failed to fetch objects from bundle URI '%s'"),
 				bundle_uri);
+		else if (flags & BUNDLE_FLAG_FOR_FETCH)
+			git_config_set_gently("fetch.bundleuri", bundle_uri);
 	}
 
 	strvec_push(&transport_ls_refs_options.ref_prefixes, "HEAD");

builtin/fetch.c

@@ -29,6 +29,7 @@
 #include "commit-graph.h"
 #include "shallow.h"
 #include "worktree.h"
+#include "bundle-uri.h"
 
 #define FORCED_UPDATES_DELAY_WARNING_IN_MS (10 * 1000)
 
@@ -2084,6 +2085,7 @@ static int fetch_one(struct remote *remote, int argc, const char **argv,
 int cmd_fetch(int argc, const char **argv, const char *prefix)
 {
 	int i;
+	const char *bundle_uri;
 	struct string_list list = STRING_LIST_INIT_DUP;
 	struct remote *remote = NULL;
 	int result = 0;
@@ -2169,6 +2171,9 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 	if (dry_run)
 		write_fetch_head = 0;
 
+	if (!git_config_get_string_tmp("fetch.bundleuri", &bundle_uri))
+		result = fetch_bundle_uri(the_repository, bundle_uri, NULL);
+
 	if (all) {
 		if (argc == 1)
 			die(_("fetch --all does not take a repository argument"));

bundle-uri.c

@@ -151,6 +151,12 @@ static int bundle_list_update(const char *key, const char *value,
 			return 0;
 		}
 
+		if (!strcmp(pkey, "flag")) {
+			if (!strcmp("forFetch", value))
+				list->flags |= BUNDLE_FLAG_FOR_FETCH;
+			return 0;
+		}
+
 		if (!strcmp(pkey, "heuristic")) {
 			int i;
 			for (i = 0; i < BUNDLE_HEURISTIC_COUNT; i++) {
@@ -562,6 +568,8 @@ static int fetch_bundle_list_in_config_format(struct repository *r,
 		goto cleanup;
 
 cleanup:
+	/* Copy results from the local list to the global list. */
+	global_list->flags |= list_from_bundle.flags;
 	clear_bundle_list(&list_from_bundle);
 	return result;
 }
@@ -686,7 +694,8 @@ static int unlink_bundle(struct remote_bundle_info *info, void *data)
 	return 0;
 }
 
-int fetch_bundle_uri(struct repository *r, const char *uri)
+int fetch_bundle_uri(struct repository *r, const char *uri,
+		     enum bundle_list_flags *flags)
 {
 	int result;
 	struct bundle_list list;
@@ -707,6 +716,8 @@ int fetch_bundle_uri(struct repository *r, const char *uri)
 	result = unbundle_all_bundles(r, &list);
 
 cleanup:
+	if (flags)
+		*flags = list.flags;
 	for_all_bundles_in_list(&list, unlink_bundle, NULL);
 	clear_bundle_list(&list);
 	clear_remote_bundle_info(&bundle, NULL);

bundle-uri.h

@@ -68,6 +68,10 @@ enum bundle_list_heuristic {
 	BUNDLE_HEURISTIC_COUNT,
 };
 
+enum bundle_list_flags {
+	BUNDLE_FLAG_FOR_FETCH = (1 << 0),
+};
+
 /**
  * A bundle_list contains an unordered set of remote_bundle_info structs,
  * as well as information about the bundle listing, such as version and
@@ -76,6 +80,7 @@ enum bundle_list_heuristic {
 struct bundle_list {
 	int version;
 	enum bundle_list_mode mode;
+	enum bundle_list_flags flags;
 	struct hashmap bundles;
 
 	/**
@@ -122,8 +127,12 @@ int parse_bundle_list_in_config_format(const char *uri,
  * based on that information.
  *
  * Returns non-zero if no bundle information is found at the given 'uri'.
+ *
+ * The enum at 'flags' (if non-NULL) is populated with the flags found at
+ * the bundle URI.
  */
-int fetch_bundle_uri(struct repository *r, const char *uri);
+int fetch_bundle_uri(struct repository *r, const char *uri,
+		     enum bundle_list_flags *flags);
 
 /**
  * Given a bundle list that was already advertised (likely by the

t/t5558-clone-bundle-uri.sh

@@ -137,6 +137,89 @@ test_expect_success 'clone bundle list (file, creationToken)' '
 	done
 '
 
+test_expect_success 'clone with bundle.flag=forFetch creates fetch.bundleURI' '
+	test_when_finished rm -rf fetch-file-3 trace1.txt trace2.txt &&
+	cat >bundle-list <<-EOF &&
+	[bundle]
+		version = 1
+		mode = all
+		heuristic = creationToken
+		flag = forFetch
+
+	[bundle "bundle-1"]
+		uri = clone-from/bundle-1.bundle
+		creationToken = 1
+	EOF
+
+	git clone --no-local --single-branch --branch=base \
+		--bundle-uri="file://$(pwd)/bundle-list" \
+		clone-from fetch-file-3 &&
+
+	test_cmp_config -C fetch-file-3 "file://$(pwd)/bundle-list" fetch.bundleuri &&
+
+	# only received base ref from bundle-1
+	git -C fetch-file-3 for-each-ref --format="%(refname)" "refs/bundles/*" >refs &&
+	cat >expect <<-\EOF &&
+	refs/bundles/base
+	EOF
+	test_cmp expect refs &&
+
+	cat >>bundle-list <<-EOF &&
+	[bundle "bundle-2"]
+		uri = clone-from/bundle-2.bundle
+		creationToken = 2
+	EOF
+
+	GIT_TRACE2_EVENT="$(pwd)/trace1.txt" \
+		git -C fetch-file-3 fetch origin --no-tags \
+		refs/heads/left:refs/heads/left &&
+
+	# This fetch should copy two files: the list and bundle-2.
+	grep "region_enter.*bundle-uri.*copy_file" trace1.txt >copies &&
+
+	# NEEDSWORK: This should only copy two files, not three.
+	test_line_count = 3 copies &&
+
+	# received left from bundle-2
+	git -C fetch-file-3 for-each-ref --format="%(refname)" "refs/bundles/*" >refs &&
+	cat >expect <<-\EOF &&
+	refs/bundles/base
+	refs/bundles/left
+	EOF
+	test_cmp expect refs &&
+
+	cat >>bundle-list <<-EOF &&
+	[bundle "bundle-3"]
+		uri = clone-from/bundle-3.bundle
+		creationToken = 3
+
+	[bundle "bundle-4"]
+		uri = clone-from/bundle-4.bundle
+		creationToken = 4
+	EOF
+
+	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" \
+		git -C fetch-file-3 fetch origin --no-tags \
+		refs/heads/right:refs/heads/right &&
+
+	# This fetch should copy three files: the list, bundle-4, and bundle-3.
+	grep "region_enter.*bundle-uri.*copy_file" trace2.txt >copies &&
+
+	# NEEDSWORK: this is re-downloading all the bundles!
+	test_line_count = 5 copies &&
+
+	# received right and merge from bundle-3 and bundle-4.
+	git -C fetch-file-3 for-each-ref --format="%(refname)" "refs/bundles/*" >refs &&
+
+	# NEEDS WORK: why not refs/bundle/merge ???
+	cat >expect <<-\EOF &&
+	refs/bundles/base
+	refs/bundles/left
+	refs/bundles/right
+	EOF
+	test_cmp expect refs
+'
+
 #########################################################################
 # HTTP tests begin here
 
@@ -248,6 +331,89 @@ test_expect_success 'fetch bundle list (http, creationToken, incremental)' '
 	test_cmp expect refs
 '
 
+test_expect_success 'http clone with bundle.flag=forFetch creates fetch.bundleURI' '
+	test_when_finished rm -rf fetch-http-4 trace1.txt trace2.txt &&
+	cat >"$HTTPD_DOCUMENT_ROOT_PATH/bundle-list" <<-EOF &&
+	[bundle]
+		version = 1
+		mode = all
+		heuristic = creationToken
+		flag = forFetch
+
+	[bundle "bundle-1"]
+		uri = bundle-1.bundle
+		creationToken = 1
+	EOF
+
+	git clone --single-branch --branch=base \
+		--bundle-uri="$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 &&
+
+	# 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 &&
+
+	cat >>"$HTTPD_DOCUMENT_ROOT_PATH/bundle-list" <<-EOF &&
+	[bundle "bundle-2"]
+		uri = bundle-2.bundle
+		creationToken = 2
+	EOF
+
+	GIT_TRACE2_EVENT="$(pwd)/trace1.txt" \
+		git -C fetch-http-4 fetch origin --no-tags \
+		refs/heads/left:refs/heads/left &&
+
+	# This fetch should copy two files: the list and bundle-2.
+	grep "region_enter.*bundle-uri.*download_https_uri_to_file" trace1.txt >copies &&
+
+	# NEEDSWORK: Currently downloading three copies instead of two!
+	test_line_count = 3 copies &&
+
+	# received left from bundle-2
+	git -C fetch-http-4 for-each-ref --format="%(refname)" "refs/bundles/*" >refs &&
+	cat >expect <<-\EOF &&
+	refs/bundles/base
+	refs/bundles/left
+	EOF
+	test_cmp expect refs &&
+
+	cat >>"$HTTPD_DOCUMENT_ROOT_PATH/bundle-list" <<-EOF &&
+	[bundle "bundle-3"]
+		uri = bundle-3.bundle
+		creationToken = 3
+
+	[bundle "bundle-4"]
+		uri = bundle-4.bundle
+		creationToken = 4
+	EOF
+
+	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" \
+		git -C fetch-http-4 fetch origin --no-tags \
+		refs/heads/right:refs/heads/right &&
+
+	# This fetch should copy three files: the list, bundle-4, and bundle-3.
+	grep "region_enter.*bundle-uri.*download_https_uri_to_file" trace2.txt >copies &&
+
+	# NEEDSWORK: this is re-downloading everything!
+	test_line_count = 5 copies &&
+
+	# received right and merge from bundle-3 and bundle-4.
+	git -C fetch-http-4 for-each-ref --format="%(refname)" "refs/bundles/*" >refs &&
+
+	# NEEDSWORK: Why not refs/bundles/merge?
+	cat >expect <<-\EOF &&
+	refs/bundles/base
+	refs/bundles/left
+	refs/bundles/right
+	EOF
+	test_cmp expect refs
+'
+
 # Do not add tests here unless they use the HTTP server, as they will
 # not run unless the HTTP dependencies exist.