merge(3p/git): Merge git subtree at v2.29.2 r/1890

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

1 files changed, 77 insertions, 10 deletions

diff --git a/third_party/git/remote.h b/third_party/git/remote.h
index 83e885672ba9..d0e3f51574c1 100644
--- a/third_party/git/remote.h
+++ b/third_party/git/remote.h
@@ -6,6 +6,14 @@
 #include "hashmap.h"
 #include "refspec.h"
 
+/**
+ * The API gives access to the configuration related to remotes. It handles
+ * all three configuration mechanisms historically and currently used by Git,
+ * and presents the information in a uniform fashion. Note that the code also
+ * handles plain URLs without any configuration, giving them just the default
+ * information.
+ */
+
 enum {
 	REMOTE_UNCONFIGURED = 0,
 	REMOTE_CONFIG,
@@ -14,18 +22,24 @@ enum {
 };
 
 struct remote {
-	struct hashmap_entry ent;  /* must be first */
+	struct hashmap_entry ent;
 
+	/* The user's nickname for the remote */
 	const char *name;
+
 	int origin, configured_in_repo;
 
 	const char *foreign_vcs;
 
+	/* An array of all of the url_nr URLs configured for the remote */
 	const char **url;
+
 	int url_nr;
 	int url_alloc;
 
+	/* An array of all of the pushurl_nr push URLs configured for the remote */
 	const char **pushurl;
+
 	int pushurl_nr;
 	int pushurl_alloc;
 
@@ -34,36 +48,59 @@ struct remote {
 	struct refspec fetch;
 
 	/*
+	 * The setting for whether to fetch tags (as a separate rule from the
+	 * configured refspecs);
 	 * -1 to never fetch tags
 	 * 0 to auto-follow tags on heuristic (default)
 	 * 1 to always auto-follow tags
 	 * 2 to always fetch tags
 	 */
 	int fetch_tags;
+
 	int skip_default_update;
 	int mirror;
 	int prune;
 	int prune_tags;
 
+	/**
+	 * The configured helper programs to run on the remote side, for
+	 * Git-native protocols.
+	 */
 	const char *receivepack;
 	const char *uploadpack;
 
-	/*
-	 * for curl remotes only
-	 */
+	/* The proxy to use for curl (http, https, ftp, etc.) URLs. */
 	char *http_proxy;
+
+	/* The method used for authenticating against `http_proxy`. */
 	char *http_proxy_authmethod;
 };
 
+/**
+ * struct remotes can be found by name with remote_get().
+ * remote_get(NULL) will return the default remote, given the current branch
+ * and configuration.
+ */
 struct remote *remote_get(const char *name);
+
 struct remote *pushremote_get(const char *name);
 int remote_is_configured(struct remote *remote, int in_repo);
 
 typedef int each_remote_fn(struct remote *remote, void *priv);
+
+/* iterate through struct remotes */
 int for_each_remote(each_remote_fn fn, void *priv);
 
 int remote_has_url(struct remote *remote, const char *url);
 
+struct ref_push_report {
+	const char *ref_name;
+	struct object_id *old_oid;
+	struct object_id *new_oid;
+	unsigned int forced_update:1;
+	struct ref_push_report *next;
+};
+
 struct ref {
 	struct ref *next;
 	struct object_id old_oid;
@@ -111,6 +148,7 @@ struct ref {
 		REF_STATUS_ATOMIC_PUSH_FAILED
 	} status;
 	char *remote_status;
+	struct ref_push_report *report;
 	struct ref *peer_ref; /* when renaming */
 	char name[FLEX_ARRAY]; /* more */
 };
@@ -139,7 +177,7 @@ void free_refs(struct ref *ref);
 
 struct oid_array;
 struct packet_reader;
-struct argv_array;
+struct strvec;
 struct string_list;
 struct ref **get_remote_heads(struct packet_reader *reader,
 			      struct ref **list, unsigned int flags,
@@ -149,8 +187,9 @@ struct ref **get_remote_heads(struct packet_reader *reader,
 /* Used for protocol v2 in order to retrieve refs from a remote */
 struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
 			     struct ref **list, int for_push,
-			     const struct argv_array *ref_prefixes,
-			     const struct string_list *server_options);
+			     const struct strvec *ref_prefixes,
+			     const struct string_list *server_options,
+			     int stateless_rpc);
 
 int resolve_remote_symref(struct ref *ref, struct ref *list);
 
@@ -163,6 +202,12 @@ int resolve_remote_symref(struct ref *ref, struct ref *list);
  */
 struct ref *ref_remove_duplicates(struct ref *ref_map);
 
+/*
+ * Remove all entries in the input list which match any negative refspec in
+ * the refspec list.
+ */
+struct ref *apply_negative_refspecs(struct ref *ref_map, struct refspec *rs);
+
 int query_refspecs(struct refspec *rs, struct refspec_item *query);
 char *apply_refspecs(struct refspec *rs, const char *name);
 
@@ -175,7 +220,8 @@ void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
 /*
  * Given a list of the remote refs and the specification of things to
  * fetch, makes a (separate) list of the refs to fetch and the local
- * refs to store into.
+ * refs to store into. Note that negative refspecs are ignored here, and
+ * should be handled separately.
  *
  * *tail is the pointer to the tail pointer of the list of results
  * beforehand, and will be set to the tail pointer of the list of
@@ -194,16 +240,36 @@ struct ref *get_remote_ref(const struct ref *remote_refs, const char *name);
  */
 int remote_find_tracking(struct remote *remote, struct refspec_item *refspec);
 
+/**
+ * struct branch holds the configuration for a branch. It can be looked up with
+ * branch_get(name) for "refs/heads/{name}", or with branch_get(NULL) for HEAD.
+ */
 struct branch {
+
+	/* The short name of the branch. */
 	const char *name;
+
+	/* The full path for the branch ref. */
 	const char *refname;
 
+	/* The name of the remote listed in the configuration. */
 	const char *remote_name;
+
 	const char *pushremote_name;
 
+	/* An array of the "merge" lines in the configuration. */
 	const char **merge_name;
+
+	/**
+	 * An array of the struct refspecs used for the merge lines. That is,
+	 * merge[i]->dst is a local tracking ref which should be merged into this
+	 * branch by default.
+	 */
 	struct refspec_item **merge;
+
+	/* The number of merge configurations */
 	int merge_nr;
+
 	int merge_alloc;
 
 	const char *push_tracking_ref;
@@ -212,10 +278,11 @@ struct branch {
 struct branch *branch_get(const char *name);
 const char *remote_for_branch(struct branch *branch, int *explicit);
 const char *pushremote_for_branch(struct branch *branch, int *explicit);
-const char *remote_ref_for_branch(struct branch *branch, int for_push,
-				  int *explicit);
+const char *remote_ref_for_branch(struct branch *branch, int for_push);
 
+/* returns true if the given branch has merge configuration given. */
 int branch_has_merge_config(struct branch *branch);
+
 int branch_merge_matches(struct branch *, int n, const char *);
 
 /**