[PATCH 2/6] builtin/receive-pack: pass shallow file explicitly

[Justin Tobler <jltobler@gmail.com>]

If shallow information is provided during `unpack()`, a temporary
shallow file is created and stored in global state. In a subsequent
commit, the `unpack()` logic is moved behind a generic ODB transaction
interface to handle writing packfiles and thus can no longer rely on
such global state. Lift the setup of the temporary shallow file out of
`unpack()` and wire it through to its call sites explicitly.

Signed-off-by: Justin Tobler <jltobler@gmail.com>
---
 builtin/receive-pack.c | 38 ++++++++++++++++++++++----------------
 1 file changed, 22 insertions(+), 16 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 420de9aa7f..6da854fca2 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -86,7 +86,6 @@ static const char *head_name;
 static void *head_name_to_free;
 static int sent_capabilities;
 static int shallow_update;
-static const char *alt_shallow_file;
 static struct strbuf push_cert = STRBUF_INIT;
 static struct object_id push_cert_oid;
 static struct signature_check sigcheck;
@@ -2334,8 +2333,8 @@ static void push_header_arg(struct strvec *args, struct pack_header *hdr)
 		     ntohl(hdr->hdr_version), ntohl(hdr->hdr_entries));
 }
 
-static const char *unpack(int err_fd, struct shallow_info *si,
-			  struct odb_transaction *transaction)
+static const char *unpack(struct odb_transaction *transaction,
+			  const char *shallow_file, int err_fd)
 {
 	struct pack_header hdr;
 	const char *hdr_err;
@@ -2354,10 +2353,9 @@ static const char *unpack(int err_fd, struct shallow_info *si,
 		return hdr_err;
 	}
 
-	if (si->nr_ours || si->nr_theirs) {
-		alt_shallow_file = setup_temporary_shallow(si->shallow);
+	if (shallow_file) {
 		strvec_push(&child.args, "--shallow-file");
-		strvec_push(&child.args, alt_shallow_file);
+		strvec_push(&child.args, shallow_file);
 	}
 
 	odb_transaction_env(transaction, &child.env);
@@ -2427,14 +2425,14 @@ static const char *unpack(int err_fd, struct shallow_info *si,
 	return NULL;
 }
 
-static const char *unpack_with_sideband(struct shallow_info *si,
-					struct odb_transaction *transaction)
+static const char *unpack_with_sideband(struct odb_transaction *transaction,
+					const char *shallow_file)
 {
 	struct async muxer;
 	const char *ret;
 
 	if (!use_sideband)
-		return unpack(0, si, transaction);
+		return unpack(transaction, shallow_file, 0);
 
 	use_keepalive = KEEPALIVE_AFTER_NUL;
 	memset(&muxer, 0, sizeof(muxer));
@@ -2443,13 +2441,14 @@ static const char *unpack_with_sideband(struct shallow_info *si,
 	if (start_async(&muxer))
 		return NULL;
 
-	ret = unpack(muxer.in, si, transaction);
+	ret = unpack(transaction, shallow_file, muxer.in);
 
 	finish_async(&muxer);
 	return ret;
 }
 
-static void prepare_shallow_update(struct shallow_info *si)
+static void prepare_shallow_update(struct shallow_info *si,
+				   const char *shallow_file)
 {
 	int i, j, k, bitmap_size = DIV_ROUND_UP(si->ref->nr, 32);
 
@@ -2489,12 +2488,13 @@ static void prepare_shallow_update(struct shallow_info *si)
 	 * command. check_connected() will be done with
 	 * true .git/shallow though.
 	 */
-	setenv(GIT_SHALLOW_FILE_ENVIRONMENT, alt_shallow_file, 1);
+	setenv(GIT_SHALLOW_FILE_ENVIRONMENT, shallow_file, 1);
 }
 
 static void update_shallow_info(struct command *commands,
 				struct shallow_info *si,
-				struct oid_array *ref)
+				struct oid_array *ref,
+				const char *shallow_file)
 {
 	struct command *cmd;
 	int *ref_status;
@@ -2513,7 +2513,7 @@ static void update_shallow_info(struct command *commands,
 	si->ref = ref;
 
 	if (shallow_update) {
-		prepare_shallow_update(si);
+		prepare_shallow_update(si, shallow_file);
 		return;
 	}
 
@@ -2705,11 +2705,17 @@ int cmd_receive_pack(int argc,
 		if (!si.nr_ours && !si.nr_theirs)
 			shallow_update = 0;
 		if (!delete_only(commands)) {
+			const char *alt_shallow_file = NULL;
+
+			if (si.nr_ours || si.nr_theirs)
+				alt_shallow_file = setup_temporary_shallow(si.shallow);
+
 			if (odb_transaction_begin(the_repository->objects, &transaction, ODB_TRANSACTION_RECEIVE))
 				unpack_status = "unable to start object transaction";
 			else
-				unpack_status = unpack_with_sideband(&si, transaction);
-			update_shallow_info(commands, &si, &ref);
+				unpack_status = unpack_with_sideband(transaction, alt_shallow_file);
+
+			update_shallow_info(commands, &si, &ref, alt_shallow_file);
 		}
 		use_keepalive = KEEPALIVE_ALWAYS;
 		execute_commands(commands, unpack_status, &si, transaction,
-- 
2.55.0.424.g13c7afec21