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, 91 insertions, 17 deletions

diff --git a/third_party/git/refs.h b/third_party/git/refs.h
index 730d05ad91a6..66955181569b 100644
--- a/third_party/git/refs.h
+++ b/third_party/git/refs.h
@@ -1,6 +1,8 @@
 #ifndef REFS_H
 #define REFS_H
 
+#include "cache.h"
+
 struct object_id;
 struct ref_store;
 struct repository;
@@ -105,6 +107,8 @@ int refs_verify_refname_available(struct ref_store *refs,
 				  const struct string_list *skip,
 				  struct strbuf *err);
 
+int refs_ref_exists(struct ref_store *refs, const char *refname);
+
 int ref_exists(const char *refname);
 
 int should_autocreate_reflog(const char *refname);
@@ -145,16 +149,31 @@ int refname_match(const char *abbrev_name, const char *full_name);
  * Given a 'prefix' expand it by the rules in 'ref_rev_parse_rules' and add
  * the results to 'prefixes'
  */
-struct argv_array;
-void expand_ref_prefix(struct argv_array *prefixes, const char *prefix);
+struct strvec;
+void expand_ref_prefix(struct strvec *prefixes, const char *prefix);
 
 int expand_ref(struct repository *r, const char *str, int len, struct object_id *oid, char **ref);
-int repo_dwim_ref(struct repository *r, const char *str, int len, struct object_id *oid, char **ref);
+int repo_dwim_ref(struct repository *r, const char *str, int len,
+		  struct object_id *oid, char **ref, int nonfatal_dangling_mark);
 int repo_dwim_log(struct repository *r, const char *str, int len, struct object_id *oid, char **ref);
-int dwim_ref(const char *str, int len, struct object_id *oid, char **ref);
+static inline int dwim_ref(const char *str, int len, struct object_id *oid,
+			   char **ref, int nonfatal_dangling_mark)
+{
+	return repo_dwim_ref(the_repository, str, len, oid, ref,
+			     nonfatal_dangling_mark);
+}
 int dwim_log(const char *str, int len, struct object_id *oid, char **ref);
 
 /*
+ * Retrieves the default branch name for newly-initialized repositories.
+ *
+ * The return value of `repo_default_branch_name()` is an allocated string. The
+ * return value of `git_default_branch_name()` is a singleton.
+ */
+const char *git_default_branch_name(void);
+char *repo_default_branch_name(struct repository *r);
+
+/*
  * A ref_transaction represents a collection of reference updates that
  * should succeed or fail together.
  *
@@ -310,19 +329,35 @@ int refs_for_each_branch_ref(struct ref_store *refs,
 int refs_for_each_remote_ref(struct ref_store *refs,
 			     each_ref_fn fn, void *cb_data);
 
+/* just iterates the head ref. */
 int head_ref(each_ref_fn fn, void *cb_data);
+
+/* iterates all refs. */
 int for_each_ref(each_ref_fn fn, void *cb_data);
+
+/**
+ * iterates all refs which have a defined prefix and strips that prefix from
+ * the passed variable refname.
+ */
 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data);
+
 int refs_for_each_fullref_in(struct ref_store *refs, const char *prefix,
 			     each_ref_fn fn, void *cb_data,
 			     unsigned int broken);
 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data,
 			unsigned int broken);
+
+/**
+ * iterate refs from the respective area.
+ */
 int for_each_tag_ref(each_ref_fn fn, void *cb_data);
 int for_each_branch_ref(each_ref_fn fn, void *cb_data);
 int for_each_remote_ref(each_ref_fn fn, void *cb_data);
 int for_each_replace_ref(struct repository *r, each_repo_ref_fn fn, void *cb_data);
+
+/* iterates all refs that match the specified glob pattern. */
 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data);
+
 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
 			 const char *prefix, void *cb_data);
 
@@ -345,18 +380,6 @@ int for_each_rawref(each_ref_fn fn, void *cb_data);
 void normalize_glob_ref(struct string_list_item *item, const char *prefix,
 			const char *pattern);
 
-/*
- * Returns 0 if refname matches any of the exclude_patterns, or if it doesn't
- * match any of the include_patterns. Returns 1 otherwise.
- *
- * If pattern list is NULL or empty, matching against that list is skipped.
- * This has the effect of matching everything by default, unless the user
- * specifies rules otherwise.
- */
-int ref_filter_match(const char *refname,
-		     const struct string_list *include_patterns,
-		     const struct string_list *exclude_patterns);
-
 static inline const char *has_glob_specials(const char *pattern)
 {
 	return strpbrk(pattern, "?*[");
@@ -428,19 +451,35 @@ int delete_refs(const char *msg, struct string_list *refnames,
 int refs_delete_reflog(struct ref_store *refs, const char *refname);
 int delete_reflog(const char *refname);
 
-/* iterate over reflog entries */
+/*
+ * Callback to process a reflog entry found by the iteration functions (see
+ * below)
+ */
 typedef int each_reflog_ent_fn(
 		struct object_id *old_oid, struct object_id *new_oid,
 		const char *committer, timestamp_t timestamp,
 		int tz, const char *msg, void *cb_data);
 
+/* Iterate over reflog entries in the log for `refname`. */
+
+/* oldest entry first */
 int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
 			     each_reflog_ent_fn fn, void *cb_data);
+
+/* youngest entry first */
 int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
 				     const char *refname,
 				     each_reflog_ent_fn fn,
 				     void *cb_data);
+
+/*
+ * Iterate over reflog entries in the log for `refname` in the main ref store.
+ */
+
+/* oldest entry first */
 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data);
+
+/* youngest entry first */
 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data);
 
 /*
@@ -791,6 +830,41 @@ int reflog_expire(const char *refname, const struct object_id *oid,
 int ref_storage_backend_exists(const char *name);
 
 struct ref_store *get_main_ref_store(struct repository *r);
+
+/**
+ * Submodules
+ * ----------
+ *
+ * If you want to iterate the refs of a submodule you first need to add the
+ * submodules object database. You can do this by a code-snippet like
+ * this:
+ *
+ * 	const char *path = "path/to/submodule"
+ * 	if (add_submodule_odb(path))
+ * 		die("Error submodule '%s' not populated.", path);
+ *
+ * `add_submodule_odb()` will return zero on success. If you
+ * do not do this you will get an error for each ref that it does not point
+ * to a valid object.
+ *
+ * Note: As a side-effect of this you cannot safely assume that all
+ * objects you lookup are available in superproject. All submodule objects
+ * will be available the same way as the superprojects objects.
+ *
+ * Example:
+ * --------
+ *
+ * ----
+ * static int handle_remote_ref(const char *refname,
+ * 		const unsigned char *sha1, int flags, void *cb_data)
+ * {
+ * 	struct strbuf *output = cb_data;
+ * 	strbuf_addf(output, "%s\n", refname);
+ * 	return 0;
+ * }
+ *
+ */
+
 /*
  * Return the ref_store instance for the specified submodule. For the
  * main repository, use submodule==NULL; such a call cannot fail. For