Merge branch 'js/partial-clone-connectivity-check'

During an initial "git clone --depth=..." partial clone, it is
pointless to spend cycles for a large portion of the connectivity
check that enumerates and skips promisor objects (which by
definition is all objects fetched from the other side).  This has
been optimized out.

* js/partial-clone-connectivity-check:
  t/perf: add perf script for partial clones
  clone: do faster object check for partial clones

Author: gitster

builtin/clone.c

@@ -660,7 +660,8 @@ static void update_remote_refs(const struct ref *refs,
 			       const char *branch_top,
 			       const char *msg,
 			       struct transport *transport,
-			       int check_connectivity)
+			       int check_connectivity,
+			       int check_refs_only)
 {
 	const struct ref *rm = mapped_refs;
 
@@ -669,6 +670,7 @@ static void update_remote_refs(const struct ref *refs,
 
 		opt.transport = transport;
 		opt.progress = transport->progress;
+		opt.check_refs_only = !!check_refs_only;
 
 		if (check_connected(iterate_ref_map, &rm, &opt))
 			die(_("remote did not send all necessary objects"));
@@ -1230,7 +1232,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 
 	update_remote_refs(refs, mapped_refs, remote_head_points_at,
 			   branch_top.buf, reflog_msg.buf, transport,
-			   !is_local);
+			   !is_local, filter_options.choice);
 
 	update_head(our_head_points_at, remote_head, reflog_msg.buf);
 

connected.c

@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "object-store.h"
 #include "run-command.h"
 #include "sigchain.h"
 #include "connected.h"
@@ -49,6 +50,22 @@ int check_connected(oid_iterate_fn fn, void *cb_data,
 		strbuf_release(&idx_file);
 	}
 
+	if (opt->check_refs_only) {
+		/*
+		 * For partial clones, we don't want to have to do a regular
+		 * connectivity check because we have to enumerate and exclude
+		 * all promisor objects (slow), and then the connectivity check
+		 * itself becomes a no-op because in a partial clone every
+		 * object is a promisor object. Instead, just make sure we
+		 * received the objects pointed to by each wanted ref.
+		 */
+		do {
+			if (!repo_has_object_file(the_repository, &oid))
+				return 1;
+		} while (!fn(cb_data, &oid));
+		return 0;
+	}
+
 	if (opt->shallow_file) {
 		argv_array_push(&rev_list.args, "--shallow-file");
 		argv_array_push(&rev_list.args, opt->shallow_file);

connected.h

@@ -46,6 +46,14 @@ struct check_connected_options {
 	 * during a fetch.
 	 */
 	unsigned is_deepening_fetch : 1;
+
+	/*
+	 * If non-zero, only check the top-level objects referenced by the
+	 * wanted refs (passed in as cb_data). This is useful for partial
+	 * clones, where enumerating and excluding all promisor objects is very
+	 * slow and the commit-walk itself becomes a no-op.
+	 */
+	unsigned check_refs_only : 1;
 };
 
 #define CHECK_CONNECTED_INIT { 0 }

t/perf/p5600-partial-clone.sh

@@ -0,0 +1,26 @@
+#!/bin/sh
+
+test_description='performance of partial clones'
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+test_expect_success 'enable server-side config' '
+	git config uploadpack.allowFilter true &&
+	git config uploadpack.allowAnySHA1InWant true
+'
+
+test_perf 'clone without blobs' '
+	rm -rf bare.git &&
+	git clone --no-local --bare --filter=blob:none . bare.git
+'
+
+test_perf 'checkout of result' '
+	rm -rf worktree &&
+	mkdir -p worktree/.git &&
+	tar -C bare.git -cf - . | tar -C worktree/.git -xf - &&
+	git -C worktree config core.bare false &&
+	git -C worktree checkout -f
+'
+
+test_done