bundle-uri: parse bundle list in config format

When a bundle provider wants to operate independently from a Git remote, they want to provide a single, consistent URI that users can use in their 'git clone --bundle-uri' commands. At this point, the Git client expects that URI to be a single bundle that can be unbundled and used to bootstrap the rest of the clone from the Git server. This single bundle cannot be re-used to assist with future incremental fetches. To allow for the incremental fetch case, teach Git to understand a bundle list that could be advertised at an independent bundle URI. Such a bundle list is likely to be inspected by human readers, even if only by the bundle provider creating the list. For this reason, we can take our expected "key=value" pairs and instead format them using Git config format. Create parse_bundle_list_in_config_format() to parse a file in config format and convert that into a 'struct bundle_list' filled with its understanding of the contents. Be careful to call git_config_from_file_with_options() because the default action for git_config_from_file() is to die() on a parsing error. The current warning isn't particularly helpful if it arises to a user, but it will be made more verbose at a higher layer later. Update 'test-tool bundle-uri' to take this config file format as input. It uses a filename instead of stdin because there is no existing way to parse a FILE pointer in the config machinery. Using git_config_from_mem() is overly complicated and more likely to introduce bugs than this simpler version. I would rather have a slightly confusing test helper than complicated product code. Signed-off-by: Derrick Stolee <derrickstolee@github.com>

Author: derrickstolee

bundle-uri.c

@@ -6,6 +6,7 @@
 #include "run-command.h"
 #include "hashmap.h"
 #include "pkt-line.h"
+#include "config.h"
 
 static int compare_bundles(const void *hashmap_cmp_fn_data,
  const struct hashmap_entry *he1,
@@ -172,6 +173,34 @@ static int bundle_list_update(const char *key, const char *value,
 return 0;
 }
 
+static int config_to_bundle_list(const char *key, const char *value, void *data)
+{
+struct bundle_list *list = data;
+return bundle_list_update(key, value, list);
+}
+
+int parse_bundle_list_in_config_format(const char *uri,
+ const char *filename,
+ struct bundle_list *list)
+{
+int result;
+struct config_options opts = {
+.error_action = CONFIG_ERROR_ERROR,
+};
+
+list->mode = BUNDLE_MODE_NONE;
+result = git_config_from_file_with_options(config_to_bundle_list,
+ filename, list,
+ &opts);
+
+if (!result && list->mode == BUNDLE_MODE_NONE) {
+warning(_("bundle list at '%s' has no mode"), uri);
+result = 1;
+}
+
+return result;
+}
+
 static int find_temp_filename(struct strbuf *name)
 {
 int fd;

bundle-uri.h

@@ -71,6 +71,16 @@ int for_all_bundles_in_list(struct bundle_list *list,
 struct FILE;
 void print_bundle_list(FILE *fp, struct bundle_list *list);
 
+/**
+ * A bundle URI may point to a bundle list where the key=value
+ * pairs are provided in config file format. This method is
+ * exposed publicly for testing purposes.
+ */
+
+int parse_bundle_list_in_config_format(const char *uri,
+ const char *filename,
+ struct bundle_list *list);
+
 /**
  * Fetch data from the given 'uri' and unbundle the bundle data found
  * based on that information.

t/helper/test-bundle-uri.c

@@ -4,27 +4,52 @@
 #include "strbuf.h"
 #include "string-list.h"
 
-static int cmd__bundle_uri_parse_key_values(int argc, const char **argv)
+enum input_mode {
+KEY_VALUE_PAIRS,
+CONFIG_FILE,
+};
+
+static int cmd__bundle_uri_parse(int argc, const char **argv, enum input_mode mode)
 {
-const char *usage[] = {
+const char *key_value_usage[] = {
 "test-tool bundle-uri parse-key-values <in",
 NULL
 };
+const char *config_usage[] = {
+"test-tool bundle-uri parse-config <input>",
+NULL
+};
 struct option options[] = {
 OPT_END(),
 };
+const char **usage = key_value_usage;
 struct strbuf sb = STRBUF_INIT;
 struct bundle_list list;
 int err = 0;
 
-argc = parse_options(argc, argv, NULL, options, usage, 0);
-if (argc)
-goto usage;
+if (mode == CONFIG_FILE)
+usage = config_usage;
+
+argc = parse_options(argc, argv, NULL, options, usage,
+ PARSE_OPT_STOP_AT_NON_OPTION);
 
 init_bundle_list(&list);
-while (strbuf_getline(&sb, stdin) != EOF) {
-if (bundle_uri_parse_line(&list, sb.buf) < 0)
-err = error("bad line: '%s'", sb.buf);
+
+switch (mode) {
+case KEY_VALUE_PAIRS:
+if (argc)
+goto usage;
+while (strbuf_getline(&sb, stdin) != EOF) {
+if (bundle_uri_parse_line(&list, sb.buf) < 0)
+err = error("bad line: '%s'", sb.buf);
+}
+break;
+
+case CONFIG_FILE:
+if (argc != 1)
+goto usage;
+err = parse_bundle_list_in_config_format("<uri>", argv[0], &list);
+break;
 }
 strbuf_release(&sb);
 
@@ -55,7 +80,9 @@ int cmd__bundle_uri(int argc, const char **argv)
 goto usage;
 
 if (!strcmp(argv[1], "parse-key-values"))
-return cmd__bundle_uri_parse_key_values(argc - 1, argv + 1);
+return cmd__bundle_uri_parse(argc - 1, argv + 1, KEY_VALUE_PAIRS);
+if (!strcmp(argv[1], "parse-config"))
+return cmd__bundle_uri_parse(argc - 1, argv + 1, CONFIG_FILE);
 error("there is no test-tool bundle-uri tool '%s'", argv[1]);
 
 usage:

t/t5750-bundle-uri-parse.sh

@@ -88,4 +88,54 @@ test_expect_success 'bundle_uri_parse_line() parsing edge cases: empty lines' '
 test_cmp_config_output expect actual
 '
 
+test_expect_success 'parse config format: just URIs' '
+cat >expect <<-\EOF &&
+[bundle]
+version = 1
+mode = all
+[bundle "one"]
+uri = http://example.com/bundle.bdl
+[bundle "two"]
+uri = https://example.com/bundle.bdl
+[bundle "three"]
+uri = file:///usr/share/git/bundle.bdl
+EOF
+
+test-tool bundle-uri parse-config expect >actual 2>err &&
+test_must_be_empty err &&
+test_cmp_config_output expect actual
+'
+
+test_expect_success 'parse config format edge cases: empty key or value' '
+cat >in1 <<-\EOF &&
+= bogus-value
+EOF
+
+cat >err1 <<-EOF &&
+error: bad config line 1 in file in1
+EOF
+
+cat >expect <<-\EOF &&
+[bundle]
+version = 1
+mode = <unknown>
+EOF
+
+test_must_fail test-tool bundle-uri parse-config in1 >actual 2>err &&
+test_cmp err1 err &&
+test_cmp_config_output expect actual &&
+
+cat >in2 <<-\EOF &&
+bogus-key =
+EOF
+
+cat >err2 <<-EOF &&
+warning: bundle list at '\''<uri>'\'' has no mode
+EOF
+
+test_must_fail test-tool bundle-uri parse-config in2 >actual 2>err &&
+test_cmp err2 err &&
+test_cmp_config_output expect actual
+'
+
 test_done