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, 158 insertions, 68 deletions

diff --git a/third_party/git/remote.c b/third_party/git/remote.c
index e50f7602ed..8be67f0892 100644
--- a/third_party/git/remote.c
+++ b/third_party/git/remote.c
@@ -11,7 +11,7 @@
 #include "tag.h"
 #include "string-list.h"
 #include "mergesort.h"
-#include "argv-array.h"
+#include "strvec.h"
 #include "commit-reach.h"
 #include "advice.h"
 
@@ -111,14 +111,16 @@ struct remotes_hash_key {
 };
 
 static int remotes_hash_cmp(const void *unused_cmp_data,
-			    const void *entry,
-			    const void *entry_or_key,
+			    const struct hashmap_entry *eptr,
+			    const struct hashmap_entry *entry_or_key,
 			    const void *keydata)
 {
-	const struct remote *a = entry;
-	const struct remote *b = entry_or_key;
+	const struct remote *a, *b;
 	const struct remotes_hash_key *key = keydata;
 
+	a = container_of(eptr, const struct remote, ent);
+	b = container_of(entry_or_key, const struct remote, ent);
+
 	if (key)
 		return strncmp(a->name, key->str, key->len) || a->name[key->len];
 	else
@@ -135,7 +137,7 @@ static struct remote *make_remote(const char *name, int len)
 {
 	struct remote *ret, *replaced;
 	struct remotes_hash_key lookup;
-	struct hashmap_entry lookup_entry;
+	struct hashmap_entry lookup_entry, *e;
 
 	if (!len)
 		len = strlen(name);
@@ -145,8 +147,9 @@ static struct remote *make_remote(const char *name, int len)
 	lookup.len = len;
 	hashmap_entry_init(&lookup_entry, memhash(name, len));
 
-	if ((ret = hashmap_get(&remotes_hash, &lookup_entry, &lookup)) != NULL)
-		return ret;
+	e = hashmap_get(&remotes_hash, &lookup_entry, &lookup);
+	if (e)
+		return container_of(e, struct remote, ent);
 
 	ret = xcalloc(1, sizeof(struct remote));
 	ret->prune = -1;  /* unspecified */
@@ -158,8 +161,8 @@ static struct remote *make_remote(const char *name, int len)
 	ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 	remotes[remotes_nr++] = ret;
 
-	hashmap_entry_init(ret, lookup_entry.hash);
-	replaced = hashmap_put(&remotes_hash, ret);
+	hashmap_entry_init(&ret->ent, lookup_entry.hash);
+	replaced = hashmap_put_entry(&remotes_hash, ret, ent);
 	assert(replaced == NULL);  /* no previous entry overwritten */
 	return ret;
 }
@@ -171,54 +174,43 @@ static void add_merge(struct branch *branch, const char *name)
 	branch->merge_name[branch->merge_nr++] = name;
 }
 
-static struct branch *make_branch(const char *name, int len)
+static struct branch *make_branch(const char *name, size_t len)
 {
 	struct branch *ret;
 	int i;
 
 	for (i = 0; i < branches_nr; i++) {
-		if (len ? (!strncmp(name, branches[i]->name, len) &&
-			   !branches[i]->name[len]) :
-		    !strcmp(name, branches[i]->name))
+		if (!strncmp(name, branches[i]->name, len) &&
+		    !branches[i]->name[len])
 			return branches[i];
 	}
 
 	ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
 	ret = xcalloc(1, sizeof(struct branch));
 	branches[branches_nr++] = ret;
-	if (len)
-		ret->name = xstrndup(name, len);
-	else
-		ret->name = xstrdup(name);
+	ret->name = xstrndup(name, len);
 	ret->refname = xstrfmt("refs/heads/%s", ret->name);
 
 	return ret;
 }
 
-static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
+static struct rewrite *make_rewrite(struct rewrites *r,
+				    const char *base, size_t len)
 {
 	struct rewrite *ret;
 	int i;
 
 	for (i = 0; i < r->rewrite_nr; i++) {
-		if (len
-		    ? (len == r->rewrite[i]->baselen &&
-		       !strncmp(base, r->rewrite[i]->base, len))
-		    : !strcmp(base, r->rewrite[i]->base))
+		if (len == r->rewrite[i]->baselen &&
+		    !strncmp(base, r->rewrite[i]->base, len))
 			return r->rewrite[i];
 	}
 
 	ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
 	ret = xcalloc(1, sizeof(struct rewrite));
 	r->rewrite[r->rewrite_nr++] = ret;
-	if (len) {
-		ret->base = xstrndup(base, len);
-		ret->baselen = len;
-	}
-	else {
-		ret->base = xstrdup(base);
-		ret->baselen = strlen(base);
-	}
+	ret->base = xstrndup(base, len);
+	ret->baselen = len;
 	return ret;
 }
 
@@ -284,7 +276,7 @@ static void read_branches_file(struct remote *remote)
 
 	/*
 	 * The branches file would have URL and optionally
-	 * #branch specified.  The "master" (or specified) branch is
+	 * #branch specified.  The default (or specified) branch is
 	 * fetched and stored in the local branch matching the
 	 * remote name.
 	 */
@@ -292,28 +284,24 @@ static void read_branches_file(struct remote *remote)
 	if (frag)
 		*(frag++) = '\0';
 	else
-		frag = "master";
+		frag = (char *)git_default_branch_name();
 
 	add_url_alias(remote, strbuf_detach(&buf, NULL));
-	strbuf_addf(&buf, "refs/heads/%s:refs/heads/%s",
-		    frag, remote->name);
-	refspec_append(&remote->fetch, buf.buf);
+	refspec_appendf(&remote->fetch, "refs/heads/%s:refs/heads/%s",
+			frag, remote->name);
 
 	/*
 	 * Cogito compatible push: push current HEAD to remote #branch
 	 * (master if missing)
 	 */
-	strbuf_reset(&buf);
-	strbuf_addf(&buf, "HEAD:refs/heads/%s", frag);
-	refspec_append(&remote->push, buf.buf);
+	refspec_appendf(&remote->push, "HEAD:refs/heads/%s", frag);
 	remote->fetch_tags = 1; /* always auto-follow */
-	strbuf_release(&buf);
 }
 
 static int handle_config(const char *key, const char *value, void *cb)
 {
 	const char *name;
-	int namelen;
+	size_t namelen;
 	const char *subkey;
 	struct remote *remote;
 	struct branch *branch;
@@ -366,7 +354,8 @@ static int handle_config(const char *key, const char *value, void *cb)
 	}
 	remote = make_remote(name, namelen);
 	remote->origin = REMOTE_CONFIG;
-	if (current_config_scope() == CONFIG_SCOPE_REPO)
+	if (current_config_scope() == CONFIG_SCOPE_LOCAL ||
+	current_config_scope() == CONFIG_SCOPE_WORKTREE)
 		remote->configured_in_repo = 1;
 	if (!strcmp(subkey, "mirror"))
 		remote->mirror = git_config_bool(key, value);
@@ -466,7 +455,7 @@ static void read_config(void)
 		const char *head_ref = resolve_ref_unsafe("HEAD", 0, NULL, &flag);
 		if (head_ref && (flag & REF_ISSYMREF) &&
 		    skip_prefix(head_ref, "refs/heads/", &head_ref)) {
-			current_branch = make_branch(head_ref, 0);
+			current_branch = make_branch(head_ref, strlen(head_ref));
 		}
 	}
 	git_config(handle_config, NULL);
@@ -512,14 +501,11 @@ const char *pushremote_for_branch(struct branch *branch, int *explicit)
 	return remote_for_branch(branch, 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)
 {
 	if (branch) {
 		if (!for_push) {
 			if (branch->merge_nr) {
-				if (explicit)
-					*explicit = 1;
 				return branch->merge_name[0];
 			}
 		} else {
@@ -530,15 +516,11 @@ const char *remote_ref_for_branch(struct branch *branch, int for_push,
 			if (remote && remote->push.nr &&
 			    (dst = apply_refspecs(&remote->push,
 						  branch->refname))) {
-				if (explicit)
-					*explicit = 1;
 				return dst;
 			}
 		}
 	}
-	if (explicit)
-		*explicit = 0;
-	return "";
+	return NULL;
 }
 
 static struct remote *remote_get_1(const char *name,
@@ -700,6 +682,91 @@ static int match_name_with_pattern(const char *key, const char *name,
 	return ret;
 }
 
+static int refspec_match(const struct refspec_item *refspec,
+			 const char *name)
+{
+	if (refspec->pattern)
+		return match_name_with_pattern(refspec->src, name, NULL, NULL);
+
+	return !strcmp(refspec->src, name);
+}
+
+static int omit_name_by_refspec(const char *name, struct refspec *rs)
+{
+	int i;
+
+	for (i = 0; i < rs->nr; i++) {
+		if (rs->items[i].negative && refspec_match(&rs->items[i], name))
+			return 1;
+	}
+	return 0;
+}
+
+struct ref *apply_negative_refspecs(struct ref *ref_map, struct refspec *rs)
+{
+	struct ref **tail;
+
+	for (tail = &ref_map; *tail; ) {
+		struct ref *ref = *tail;
+
+		if (omit_name_by_refspec(ref->name, rs)) {
+			*tail = ref->next;
+			free(ref->peer_ref);
+			free(ref);
+		} else
+			tail = &ref->next;
+	}
+
+	return ref_map;
+}
+
+static int query_matches_negative_refspec(struct refspec *rs, struct refspec_item *query)
+{
+	int i, matched_negative = 0;
+	int find_src = !query->src;
+	struct string_list reversed = STRING_LIST_INIT_NODUP;
+	const char *needle = find_src ? query->dst : query->src;
+
+	/*
+	 * Check whether the queried ref matches any negative refpsec. If so,
+	 * then we should ultimately treat this as not matching the query at
+	 * all.
+	 *
+	 * Note that negative refspecs always match the source, but the query
+	 * item uses the destination. To handle this, we apply pattern
+	 * refspecs in reverse to figure out if the query source matches any
+	 * of the negative refspecs.
+	 */
+	for (i = 0; i < rs->nr; i++) {
+		struct refspec_item *refspec = &rs->items[i];
+		char *expn_name;
+
+		if (refspec->negative)
+			continue;
+
+		/* Note the reversal of src and dst */
+		if (refspec->pattern) {
+			const char *key = refspec->dst ? refspec->dst : refspec->src;
+			const char *value = refspec->src;
+
+			if (match_name_with_pattern(key, needle, value, &expn_name))
+				string_list_append_nodup(&reversed, expn_name);
+		} else {
+			if (!strcmp(needle, refspec->src))
+				string_list_append(&reversed, refspec->src);
+		}
+	}
+
+	for (i = 0; !matched_negative && i < reversed.nr; i++) {
+		if (omit_name_by_refspec(reversed.items[i].string, rs))
+			matched_negative = 1;
+	}
+
+	string_list_clear(&reversed, 0);
+
+	return matched_negative;
+}
+
 static void query_refspecs_multiple(struct refspec *rs,
 				    struct refspec_item *query,
 				    struct string_list *results)
@@ -710,6 +777,9 @@ static void query_refspecs_multiple(struct refspec *rs,
 	if (find_src && !query->dst)
 		BUG("query_refspecs_multiple: need either src or dst");
 
+	if (query_matches_negative_refspec(rs, query))
+		return;
+
 	for (i = 0; i < rs->nr; i++) {
 		struct refspec_item *refspec = &rs->items[i];
 		const char *key = find_src ? refspec->dst : refspec->src;
@@ -717,7 +787,7 @@ static void query_refspecs_multiple(struct refspec *rs,
 		const char *needle = find_src ? query->dst : query->src;
 		char **result = find_src ? &query->src : &query->dst;
 
-		if (!refspec->dst)
+		if (!refspec->dst || refspec->negative)
 			continue;
 		if (refspec->pattern) {
 			if (match_name_with_pattern(key, needle, value, result))
@@ -738,12 +808,15 @@ int query_refspecs(struct refspec *rs, struct refspec_item *query)
 	if (find_src && !query->dst)
 		BUG("query_refspecs: need either src or dst");
 
+	if (query_matches_negative_refspec(rs, query))
+		return -1;
+
 	for (i = 0; i < rs->nr; i++) {
 		struct refspec_item *refspec = &rs->items[i];
 		const char *key = find_src ? refspec->dst : refspec->src;
 		const char *value = find_src ? refspec->src : refspec->dst;
 
-		if (!refspec->dst)
+		if (!refspec->dst || refspec->negative)
 			continue;
 		if (refspec->pattern) {
 			if (match_name_with_pattern(key, needle, value, result)) {
@@ -1072,7 +1145,7 @@ static int match_explicit(struct ref *src, struct ref *dst,
 	const char *dst_value = rs->dst;
 	char *dst_guess;
 
-	if (rs->pattern || rs->matching)
+	if (rs->pattern || rs->matching || rs->negative)
 		return 0;
 
 	matched_src = matched_dst = NULL;
@@ -1148,6 +1221,10 @@ static char *get_ref_match(const struct refspec *rs, const struct ref *ref,
 	int matching_refs = -1;
 	for (i = 0; i < rs->nr; i++) {
 		const struct refspec_item *item = &rs->items[i];
+
+		if (item->negative)
+			continue;
+
 		if (item->matching &&
 		    (matching_refs == -1 || item->force)) {
 			matching_refs = i;
@@ -1353,7 +1430,7 @@ int check_push_refs(struct ref *src, struct refspec *rs)
 	for (i = 0; i < rs->nr; i++) {
 		struct refspec_item *item = &rs->items[i];
 
-		if (item->pattern || item->matching)
+		if (item->pattern || item->matching || item->negative)
 			continue;
 
 		ret |= match_explicit_lhs(src, item, NULL, NULL);
@@ -1455,6 +1532,8 @@ int match_push_refs(struct ref *src, struct ref **dst,
 		string_list_clear(&src_ref_index, 0);
 	}
 
+	*dst = apply_negative_refspecs(*dst, rs);
+
 	if (errs)
 		return -1;
 	return 0;
@@ -1572,7 +1651,7 @@ static void set_merge(struct branch *ret)
 		    strcmp(ret->remote_name, "."))
 			continue;
 		if (dwim_ref(ret->merge_name[i], strlen(ret->merge_name[i]),
-			     &oid, &ref) == 1)
+			     &oid, &ref, 0) == 1)
 			ret->merge[i]->dst = ref;
 		else
 			ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
@@ -1587,7 +1666,7 @@ struct branch *branch_get(const char *name)
 	if (!name || !*name || !strcmp(name, "HEAD"))
 		ret = current_branch;
 	else
-		ret = make_branch(name, 0);
+		ret = make_branch(name, strlen(name));
 	set_merge(ret);
 	return ret;
 }
@@ -1824,6 +1903,9 @@ int get_fetch_map(const struct ref *remote_refs,
 {
 	struct ref *ref_map, **rmp;
 
+	if (refspec->negative)
+		return 0;
+
 	if (refspec->pattern) {
 		ref_map = get_expanded_map(remote_refs, refspec);
 	} else {
@@ -1899,7 +1981,7 @@ static int stat_branch_pair(const char *branch_name, const char *base,
 	struct object_id oid;
 	struct commit *ours, *theirs;
 	struct rev_info revs;
-	struct argv_array argv = ARGV_ARRAY_INIT;
+	struct strvec argv = STRVEC_INIT;
 
 	/* Cannot stat if what we used to build on no longer exists */
 	if (read_ref(base, &oid))
@@ -1925,15 +2007,15 @@ static int stat_branch_pair(const char *branch_name, const char *base,
 		BUG("stat_branch_pair: invalid abf '%d'", abf);
 
 	/* Run "rev-list --left-right ours...theirs" internally... */
-	argv_array_push(&argv, ""); /* ignored */
-	argv_array_push(&argv, "--left-right");
-	argv_array_pushf(&argv, "%s...%s",
-			 oid_to_hex(&ours->object.oid),
-			 oid_to_hex(&theirs->object.oid));
-	argv_array_push(&argv, "--");
+	strvec_push(&argv, ""); /* ignored */
+	strvec_push(&argv, "--left-right");
+	strvec_pushf(&argv, "%s...%s",
+		     oid_to_hex(&ours->object.oid),
+		     oid_to_hex(&theirs->object.oid));
+	strvec_push(&argv, "--");
 
 	repo_init_revisions(the_repository, &revs, NULL);
-	setup_revisions(argv.argc, argv.argv, &revs, NULL);
+	setup_revisions(argv.nr, argv.v, &revs, NULL);
 	if (prepare_revision_walk(&revs))
 		die(_("revision walk setup failed"));
 
@@ -1952,7 +2034,7 @@ static int stat_branch_pair(const char *branch_name, const char *base,
 	clear_commit_marks(ours, ALL_REV_FLAGS);
 	clear_commit_marks(theirs, ALL_REV_FLAGS);
 
-	argv_array_clear(&argv);
+	strvec_clear(&argv);
 	return 1;
 }
 
@@ -2111,8 +2193,16 @@ struct ref *guess_remote_head(const struct ref *head,
 	if (head->symref)
 		return copy_ref(find_ref_by_name(refs, head->symref));
 
-	/* If refs/heads/master could be right, it is. */
+	/* If a remote branch exists with the default branch name, let's use it. */
 	if (!all) {
+		char *ref = xstrfmt("refs/heads/%s", git_default_branch_name());
+
+		r = find_ref_by_name(refs, ref);
+		free(ref);
+		if (r && oideq(&r->old_oid, &head->old_oid))
+			return copy_ref(r);
+
+		/* Fall back to the hard-coded historical default */
 		r = find_ref_by_name(refs, "refs/heads/master");
 		if (r && oideq(&r->old_oid, &head->old_oid))
 			return copy_ref(r);