merge(3p/git): Merge git subtree at v2.29.2

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

third_party/git/http-fetch.c

@@ -5,59 +5,24 @@
 #include "walker.h"
 
 static const char http_fetch_usage[] = "git http-fetch "
-"[-c] [-t] [-a] [-v] [--recover] [-w ref] [--stdin] commit-id url";
+"[-c] [-t] [-a] [-v] [--recover] [-w ref] [--stdin | --packfile=hash | commit-id] url";
 
-int cmd_main(int argc, const char **argv)
+static int fetch_using_walker(const char *raw_url, int get_verbosely,
+			      int get_recover, int commits, char **commit_id,
+			      const char **write_ref, int commits_on_stdin)
 {
-	struct walker *walker;
-	int commits_on_stdin = 0;
-	int commits;
-	const char **write_ref = NULL;
-	char **commit_id;
 	char *url = NULL;
-	int arg = 1;
-	int rc = 0;
-	int get_verbosely = 0;
-	int get_recover = 0;
+	struct walker *walker;
+	int rc;
 
-	while (arg < argc && argv[arg][0] == '-') {
-		if (argv[arg][1] == 't') {
-		} else if (argv[arg][1] == 'c') {
-		} else if (argv[arg][1] == 'a') {
-		} else if (argv[arg][1] == 'v') {
-			get_verbosely = 1;
-		} else if (argv[arg][1] == 'w') {
-			write_ref = &argv[arg + 1];
-			arg++;
-		} else if (argv[arg][1] == 'h') {
-			usage(http_fetch_usage);
-		} else if (!strcmp(argv[arg], "--recover")) {
-			get_recover = 1;
-		} else if (!strcmp(argv[arg], "--stdin")) {
-			commits_on_stdin = 1;
-		}
-		arg++;
-	}
-	if (argc != arg + 2 - commits_on_stdin)
-		usage(http_fetch_usage);
-	if (commits_on_stdin) {
-		commits = walker_targets_stdin(&commit_id, &write_ref);
-	} else {
-		commit_id = (char **) &argv[arg++];
-		commits = 1;
-	}
-
-	if (argv[arg])
-		str_end_url_with_slash(argv[arg], &url);
-
-	setup_git_directory();
-
-	git_config(git_default_config, NULL);
+	str_end_url_with_slash(raw_url, &url);
 
 	http_init(NULL, url, 0);
+
 	walker = get_http_walker(url);
 	walker->get_verbosely = get_verbosely;
 	walker->get_recover = get_recover;
+	walker->get_progress = 0;
 
 	rc = walker_fetch(walker, commits, commit_id, write_ref, url);
 
@@ -73,8 +38,103 @@ int cmd_main(int argc, const char **argv)
 
 	walker_free(walker);
 	http_cleanup();
-
 	free(url);
 
 	return rc;
 }
+
+static void fetch_single_packfile(struct object_id *packfile_hash,
+				  const char *url) {
+	struct http_pack_request *preq;
+	struct slot_results results;
+	int ret;
+
+	http_init(NULL, url, 0);
+
+	preq = new_direct_http_pack_request(packfile_hash->hash, xstrdup(url));
+	if (preq == NULL)
+		die("couldn't create http pack request");
+	preq->slot->results = &results;
+	preq->generate_keep = 1;
+
+	if (start_active_slot(preq->slot)) {
+		run_active_slot(preq->slot);
+		if (results.curl_result != CURLE_OK) {
+			die("Unable to get pack file %s\n%s", preq->url,
+			    curl_errorstr);
+		}
+	} else {
+		die("Unable to start request");
+	}
+
+	if ((ret = finish_http_pack_request(preq)))
+		die("finish_http_pack_request gave result %d", ret);
+
+	release_http_pack_request(preq);
+	http_cleanup();
+}
+
+int cmd_main(int argc, const char **argv)
+{
+	int commits_on_stdin = 0;
+	int commits;
+	const char **write_ref = NULL;
+	char **commit_id;
+	int arg = 1;
+	int get_verbosely = 0;
+	int get_recover = 0;
+	int packfile = 0;
+	int nongit;
+	struct object_id packfile_hash;
+
+	setup_git_directory_gently(&nongit);
+
+	while (arg < argc && argv[arg][0] == '-') {
+		const char *p;
+
+		if (argv[arg][1] == 't') {
+		} else if (argv[arg][1] == 'c') {
+		} else if (argv[arg][1] == 'a') {
+		} else if (argv[arg][1] == 'v') {
+			get_verbosely = 1;
+		} else if (argv[arg][1] == 'w') {
+			write_ref = &argv[arg + 1];
+			arg++;
+		} else if (argv[arg][1] == 'h') {
+			usage(http_fetch_usage);
+		} else if (!strcmp(argv[arg], "--recover")) {
+			get_recover = 1;
+		} else if (!strcmp(argv[arg], "--stdin")) {
+			commits_on_stdin = 1;
+		} else if (skip_prefix(argv[arg], "--packfile=", &p)) {
+			const char *end;
+
+			packfile = 1;
+			if (parse_oid_hex(p, &packfile_hash, &end) || *end)
+				die(_("argument to --packfile must be a valid hash (got '%s')"), p);
+		}
+		arg++;
+	}
+	if (argc != arg + 2 - (commits_on_stdin || packfile))
+		usage(http_fetch_usage);
+
+	if (nongit)
+		die(_("not a git repository"));
+
+	git_config(git_default_config, NULL);
+
+	if (packfile) {
+		fetch_single_packfile(&packfile_hash, argv[arg]);
+		return 0;
+	}
+
+	if (commits_on_stdin) {
+		commits = walker_targets_stdin(&commit_id, &write_ref);
+	} else {
+		commit_id = (char **) &argv[arg++];
+		commits = 1;
+	}
+	return fetch_using_walker(argv[arg], get_verbosely, get_recover,
+				  commits, commit_id, write_ref,
+				  commits_on_stdin);
+}