Merge branch 'cc/lop-filter-auto' into seen

"auto filter" logic for large-object promisor remote.

Comments?

* cc/lop-filter-auto:
  fetch-pack: wire up and enable auto filter logic
  promisor-remote: keep advertised filter in memory
  list-objects-filter-options: implement auto filter resolution
  list-objects-filter-options: support 'auto' mode for --filter
  doc: fetch: document `--filter=<filter-spec>` option
  fetch: make filter_options local to cmd_fetch()
  clone: make filter_options local to cmd_clone()
  promisor-remote: allow a client to store fields
  promisor-remote: refactor initialising field lists

Author: gitster

Documentation/config/promisor.adoc

@@ -89,3 +89,36 @@ variable. The fields are checked only if the
 `promisor.acceptFromServer` config variable is not set to "None". If
 set to "None", this config variable has no effect. See
 linkgit:gitprotocol-v2[5].
+
+promisor.storeFields::
+	A comma or space separated list of additional remote related
+	field names. If a client accepts an advertised remote, the
+	client will store the values associated with these field names
+	taken from the remote advertisement into its configuration,
+	and then reload its remote configuration. Currently,
+	"partialCloneFilter" and "token" are the only supported field
+	names.
++
+For example if a server advertises "partialCloneFilter=blob:limit=20k"
+for remote "foo", and that remote is accepted, then "blob:limit=20k"
+will be stored for the "remote.foo.partialCloneFilter" configuration
+variable.
++
+If the new field value from an advertised remote is the same as the
+existing field value for that remote on the client side, then no
+change is made to the client configuration though.
++
+When a new value is stored, a message is printed to standard error to
+let users know about this.
++
+Note that for security reasons, if the remote is not already
+configured on the client side, nothing will be stored for that
+remote. In any case, no new remote will be created and no URL will be
+stored.
++
+Before storing a partial clone filter, it's parsed to check it's
+valid. If it's not, a warning is emitted and it's not stored.
++
+Before storing a token, a check is performed to ensure it contains no
+control character. If the check fails, a warning is emitted and it's
+not stored.

Documentation/fetch-options.adoc

@@ -88,6 +88,25 @@ linkgit:git-config[1].
 This is incompatible with `--recurse-submodules=(yes|on-demand)` and takes
 precedence over the `fetch.output` config option.
 
+--filter=<filter-spec>::
+	Use the partial clone feature and request that the server sends
+	a subset of reachable objects according to a given object filter.
+	When using `--filter`, the supplied _<filter-spec>_ is used for
+	the partial fetch.
++
+If `--filter=auto` is used, the filter specification is determined
+automatically by combining the filter specifications advertised by
+the server for the promisor remotes that the client accepts (see
+linkgit:gitprotocol-v2[5] and the `promisor.acceptFromServer`
+configuration option in linkgit:git-config[1]).
++
+For details on all other available filter specifications, see the
+`--filter=<filter-spec>` option in linkgit:git-rev-list[1].
++
+For example, `--filter=blob:none` will filter out all blobs (file
+contents) until needed by Git. Also, `--filter=blob:limit=<size>` will
+filter out all blobs of size at least _<size>_.
+
 ifndef::git-pull[]
 `--write-fetch-head`::
 `--no-write-fetch-head`::

Documentation/git-clone.adoc

@@ -187,11 +187,26 @@ objects from the source repository into a pack in the cloned repository.
 	Use the partial clone feature and request that the server sends
 	a subset of reachable objects according to a given object filter.
 	When using `--filter`, the supplied _<filter-spec>_ is used for
-	the partial clone filter. For example, `--filter=blob:none` will
-	filter out all blobs (file contents) until needed by Git. Also,
-	`--filter=blob:limit=<size>` will filter out all blobs of size
-	at least _<size>_. For more details on filter specifications, see
-	the `--filter` option in linkgit:git-rev-list[1].
+	the partial clone filter.
++
+If `--filter=auto` is used the filter specification is determined
+automatically through the 'promisor-remote' protocol (see
+linkgit:gitprotocol-v2[5]) by combining the filter specifications
+advertised by the server for the promisor remotes that the client
+accepts (see the `promisor.acceptFromServer` configuration option in
+linkgit:git-config[1]). This allows the server to suggest the optimal
+filter for the available promisor remotes.
++
+As with other filter specifications, the "auto" value is persisted in
+the configuration. This ensures that future fetches will continue to
+adapt to the server's current recommendation.
++
+For details on all other available filter specifications, see the
+`--filter=<filter-spec>` option in linkgit:git-rev-list[1].
++
+For example, `--filter=blob:none` will filter out all blobs (file
+contents) until needed by Git. Also, `--filter=blob:limit=<size>` will
+filter out all blobs of size at least _<size>_.
 
 `--also-filter-submodules`::
 	Also apply the partial clone filter to any submodules in the repository.

Documentation/gitprotocol-v2.adoc

@@ -812,10 +812,15 @@ MUST appear first in each pr-fields, in that order.
 After these mandatory fields, the server MAY advertise the following
 optional fields in any order:
 
-`partialCloneFilter`:: The filter specification used by the remote.
+`partialCloneFilter`:: The filter specification for the remote. It
+corresponds to the "remote.<name>.partialCloneFilter" config setting.
 Clients can use this to determine if the remote's filtering strategy
-is compatible with their needs (e.g., checking if both use "blob:none").
-It corresponds to the "remote.<name>.partialCloneFilter" config setting.
+is compatible with their needs (e.g., checking if both use
+"blob:none"). Additionally they can use this through the
+`--filter=auto` option in linkgit:git-clone[1]. With that option, the
+filter specification of the clone will be automatically computed by
+combining the filter specifications of the promisor remotes the client
+accepts.
 
 `token`:: An authentication token that clients can use when
 connecting to the remote. It corresponds to the "remote.<name>.token"
@@ -826,9 +831,11 @@ are case-sensitive and MUST be transmitted exactly as specified
 above. Clients MUST ignore fields they don't recognize to allow for
 future protocol extensions.
 
-For now, the client can only use information transmitted through these
-fields to decide if it accepts the advertised promisor remote. In the
-future that information might be used for other purposes though.
+The client can use information transmitted through these fields to
+decide if it accepts the advertised promisor remote. Also, the client
+can be configured to store the values of these fields or use them
+to automatically configure the repository (see "promisor.storeFields"
+in linkgit:git-config[1] and `--filter=auto` in linkgit:git-clone[1]).
 
 Field values MUST be urlencoded.
 
@@ -856,8 +863,9 @@ the server advertised, the client shouldn't advertise the
 On the server side, the "promisor.advertise" and "promisor.sendFields"
 configuration options can be used to control what it advertises. On
 the client side, the "promisor.acceptFromServer" configuration option
-can be used to control what it accepts. See the documentation of these
-configuration options for more information.
+can be used to control what it accepts, and the "promisor.storeFields"
+option, to control what it stores. See the documentation of these
+configuration options in linkgit:git-config[1] for more information.
 
 Note that in the future it would be nice if the "promisor-remote"
 protocol capability could be used by the server, when responding to

Makefile

@@ -1517,6 +1517,7 @@ CLAR_TEST_SUITES += u-dir
 CLAR_TEST_SUITES += u-example-decorate
 CLAR_TEST_SUITES += u-hash
 CLAR_TEST_SUITES += u-hashmap
+CLAR_TEST_SUITES += u-list-objects-filter-options
 CLAR_TEST_SUITES += u-mem-pool
 CLAR_TEST_SUITES += u-oid-array
 CLAR_TEST_SUITES += u-oidmap

builtin/clone.c

@@ -77,7 +77,6 @@ static struct string_list option_required_reference = STRING_LIST_INIT_NODUP;
 static struct string_list option_optional_reference = STRING_LIST_INIT_NODUP;
 static int max_jobs = -1;
 static struct string_list option_recurse_submodules = STRING_LIST_INIT_NODUP;
-static struct list_objects_filter_options filter_options = LIST_OBJECTS_FILTER_INIT;
 static int config_filter_submodules = -1;    /* unspecified */
 static int option_remote_submodules;
 
@@ -634,7 +633,9 @@ static int git_sparse_checkout_init(const char *repo)
 	return result;
 }
 
-static int checkout(int submodule_progress, int filter_submodules,
+static int checkout(int submodule_progress,
+		    struct list_objects_filter_options *filter_options,
+		    int filter_submodules,
 		    enum ref_storage_format ref_storage_format)
 {
 	struct object_id oid;
@@ -723,9 +724,9 @@ static int checkout(int submodule_progress, int filter_submodules,
 			strvec_pushf(&cmd.args, "--ref-format=%s",
 				     ref_storage_format_to_name(ref_storage_format));
 
-		if (filter_submodules && filter_options.choice)
+		if (filter_submodules && filter_options->choice)
 			strvec_pushf(&cmd.args, "--filter=%s",
-				     expand_list_objects_filter_spec(&filter_options));
+				     expand_list_objects_filter_spec(filter_options));
 
 		if (option_single_branch >= 0)
 			strvec_push(&cmd.args, option_single_branch ?
@@ -903,6 +904,7 @@ int cmd_clone(int argc,
 	enum transport_family family = TRANSPORT_FAMILY_ALL;
 	struct string_list option_config = STRING_LIST_INIT_DUP;
 	int option_dissociate = 0;
+	struct list_objects_filter_options filter_options = LIST_OBJECTS_FILTER_INIT;
 	int option_filter_submodules = -1; /* unspecified */
 	struct string_list server_options = STRING_LIST_INIT_NODUP;
 	const char *bundle_uri = NULL;
@@ -999,6 +1001,8 @@ int cmd_clone(int argc,
 		NULL
 	};
 
+	filter_options.allow_auto_filter = 1;
+
 	packet_trace_identity("clone");
 
 	repo_config(the_repository, git_clone_config, NULL);
@@ -1625,9 +1629,13 @@ int cmd_clone(int argc,
 		return 1;
 
 	junk_mode = JUNK_LEAVE_REPO;
-	err = checkout(submodule_progress, filter_submodules,
+	err = checkout(submodule_progress,
+		       &filter_options,
+		       filter_submodules,
 		       ref_storage_format);
 
+	list_objects_filter_release(&filter_options);
+
 	string_list_clear(&option_not, 0);
 	string_list_clear(&option_config, 0);
 	string_list_clear(&server_options, 0);