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 bundle_uri_parse_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 use error_action CONFIG_ERROR_ERROR when calling
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.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 50 insertions, 0 deletions

diff --git a/t/t5750-bundle-uri-parse.sh b/t/t5750-bundle-uri-parse.sh
index fd142a66ad..c2fe3f9c5a 100755
--- a/t/t5750-bundle-uri-parse.sh
+++ b/t/t5750-bundle-uri-parse.sh
@@ -118,4 +118,54 @@ test_expect_success 'bundle_uri_parse_line() parsing edge cases: duplicate 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 = all
+	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 &&
+	error: bad config line 1 in file in2
+	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