clone: unbundle the advertised bundles

A previous change introduced the transport methods to acquire a bundle
list from the 'bundle-uri' protocol v2 verb, when advertised _and_ when
the client has chosen to enable the feature.

Teach Git to download and unbundle the data advertised by those bundles
during 'git clone'.

Also, since the --bundle-uri option exists, we do not want to mix the
advertised bundles with the user-specified bundles.

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

builtin/clone.c

@@ -1267,11 +1267,27 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	if (refs)
 		mapped_refs = wanted_peer_refs(refs, &remote->fetch);
 
-	/*
-	 * Populate transport->got_remote_bundle_uri and
-	 * transport->bundle_uri. We might get nothing.
-	 */
-	transport_get_remote_bundle_uri(transport, 1);
+	if (!bundle_uri) {
+		/*
+		* Populate transport->got_remote_bundle_uri and
+		* transport->bundle_uri. We might get nothing.
+		*/
+		transport_get_remote_bundle_uri(transport, 1);
+
+		if (transport->bundles &&
+		    hashmap_get_size(&transport->bundles->bundles)) {
+			/* 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"));
+			if (fetch_bundle_list(the_repository,
+					      remote->url[0],
+					      transport->bundles))
+				warning(_("failed to fetch advertised bundles"));
+		} else {
+			clear_bundle_list(transport->bundles);
+			FREE_AND_NULL(transport->bundles);
+		}
+	}
 
 	if (mapped_refs) {
 		int hash_algo = hash_algo_by_ptr(transport_get_hash_algo(transport));

t/t5601-clone.sh

@@ -795,6 +795,65 @@ test_expect_success 'reject cloning shallow repository using HTTP' '
 	git clone --no-reject-shallow $HTTPD_URL/smart/repo.git repo
 '
 
+test_expect_success 'auto-discover bundle URI from HTTP clone' '
+	test_when_finished rm -rf trace.txt repo2 "$HTTPD_DOCUMENT_ROOT_PATH/repo2.git" &&
+	git -C src bundle create "$HTTPD_DOCUMENT_ROOT_PATH/everything.bundle" --all &&
+	git clone --bare --no-local src "$HTTPD_DOCUMENT_ROOT_PATH/repo2.git" &&
+
+	git -C "$HTTPD_DOCUMENT_ROOT_PATH/repo2.git" config \
+		uploadpack.advertiseBundleURIs true &&
+	git -C "$HTTPD_DOCUMENT_ROOT_PATH/repo2.git" config \
+		bundle.version 1 &&
+	git -C "$HTTPD_DOCUMENT_ROOT_PATH/repo2.git" config \
+		bundle.mode all &&
+	git -C "$HTTPD_DOCUMENT_ROOT_PATH/repo2.git" config \
+		bundle.everything.uri "$HTTPD_URL/everything.bundle" &&
+
+	GIT_TEST_BUNDLE_URI=1 \
+	GIT_TRACE2_EVENT="$(pwd)/trace.txt" \
+		git -c protocol.version=2 clone \
+		$HTTPD_URL/smart/repo2.git repo2 &&
+	cat >pattern <<-EOF &&
+	"event":"child_start".*"argv":\["git-remote-https","$HTTPD_URL/everything.bundle"\]
+	EOF
+	grep -f pattern trace.txt
+'
+
+test_expect_success 'auto-discover multiple bundles from HTTP clone' '
+	test_when_finished rm -rf trace.txt repo3 "$HTTPD_DOCUMENT_ROOT_PATH/repo3.git" &&
+
+	test_commit -C src new &&
+	git -C src bundle create "$HTTPD_DOCUMENT_ROOT_PATH/new.bundle" HEAD~1..HEAD &&
+	git clone --bare --no-local src "$HTTPD_DOCUMENT_ROOT_PATH/repo3.git" &&
+
+	git -C "$HTTPD_DOCUMENT_ROOT_PATH/repo3.git" config \
+		uploadpack.advertiseBundleURIs true &&
+	git -C "$HTTPD_DOCUMENT_ROOT_PATH/repo3.git" config \
+		bundle.version 1 &&
+	git -C "$HTTPD_DOCUMENT_ROOT_PATH/repo3.git" config \
+		bundle.mode all &&
+
+	git -C "$HTTPD_DOCUMENT_ROOT_PATH/repo3.git" config \
+		bundle.everything.uri "$HTTPD_URL/everything.bundle" &&
+	git -C "$HTTPD_DOCUMENT_ROOT_PATH/repo3.git" config \
+		bundle.new.uri "$HTTPD_URL/new.bundle" &&
+
+	GIT_TEST_BUNDLE_URI=1 \
+	GIT_TRACE2_EVENT="$(pwd)/trace.txt" \
+		git -c protocol.version=2 clone \
+		$HTTPD_URL/smart/repo3.git repo3 &&
+
+	# We should fetch _both_ bundles
+	cat >pattern <<-EOF &&
+	"event":"child_start".*"argv":\["git-remote-https","$HTTPD_URL/everything.bundle"\]
+	EOF
+	grep -f pattern trace.txt &&
+	cat >pattern <<-EOF &&
+	"event":"child_start".*"argv":\["git-remote-https","$HTTPD_URL/new.bundle"\]
+	EOF
+	grep -f pattern trace.txt
+'
+
 # DO NOT add non-httpd-specific tests here, because the last part of this
 # test script is only executed when httpd is available and enabled.