[PATCH 3/7] remote-curl: rediscover repository when fetching refs

From: Patrick Steinhardt <ps@pks.im>
Date: Dec 6, 2023, 12:39 UTC
Message-ID: <a1b86a0cbbedcc6610b2c563e9e38d439338869d.1701863960.git.ps@pks.im>
In-Reply-To: <cover.1701863960.git.ps@pks.im>

We're about to change git-clone(1) so that we set up the reference database at a later point. This change will cause git-remote-curl(1) to not detect the repository anymore due to "HEAD" not having been created yet at the time it spawns, and thus causes it to error out once it is asked to fetch the references.

We can address this issue by trying to re-discover the Git repository in case none was detected at startup time. With this change, the clone will look as following:

  1. git-clone(1) sets up the initial repository, excluding the
     reference database.

  2. git-clone(1) spawns git-remote-curl(1), which will be unable to
     detect the repository due to a missing "HEAD".

  3. git-clone(1) asks git-remote-curl(1) to list remote references.
     This works just fine as this step does not require a local
     repository

  4. git-clone(1) creates the reference database as it has now learned
     about the object format.

  5. git-clone(1) asks git-remote-curl(1) to fetch the remote packfile.
     The latter notices that it doesn't have a repository available, but
     it now knows to try and re-discover it.

If the re-discovery succeeds in the last step we can continue with the clone.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 remote-curl.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/remote-curl.c b/remote-curl.c
index ef05752ca5..fc29757b65 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -1564,8 +1564,11 @@ int cmd_main(int argc, const char **argv)
 		if (buf.len == 0)
 			break;
 		if (starts_with(buf.buf, "fetch ")) {
-			if (nongit)
-				die(_("remote-curl: fetch attempted without a local repo"));
+			if (nongit) {
+				setup_git_directory_gently(&nongit);
+				if (nongit)
+					die(_("remote-curl: fetch attempted without a local repo"));
+			}
 			parse_fetch(&buf);
 
 		} else if (!strcmp(buf.buf, "list") || starts_with(buf.buf, "list ")) {

-- 
2.43.0