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, 117 insertions, 45 deletions

diff --git a/third_party/git/commit.c b/third_party/git/commit.c
index a98de16e3d57..f53429c0ac34 100644
--- a/third_party/git/commit.c
+++ b/third_party/git/commit.c
@@ -19,6 +19,8 @@
 #include "advice.h"
 #include "refs.h"
 #include "commit-reach.h"
+#include "run-command.h"
+#include "shallow.h"
 
 static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
 
@@ -35,7 +37,7 @@ struct commit *lookup_commit_reference_gently(struct repository *r,
 
 	if (!obj)
 		return NULL;
-	return object_as_type(r, obj, OBJ_COMMIT, quiet);
+	return object_as_type(obj, OBJ_COMMIT, quiet);
 }
 
 struct commit *lookup_commit_reference(struct repository *r, const struct object_id *oid)
@@ -60,7 +62,7 @@ struct commit *lookup_commit(struct repository *r, const struct object_id *oid)
 	struct object *obj = lookup_object(r, oid);
 	if (!obj)
 		return create_object(r, oid, alloc_commit_node(r));
-	return object_as_type(r, obj, OBJ_COMMIT, 0);
+	return object_as_type(obj, OBJ_COMMIT, 0);
 }
 
 struct commit *lookup_commit_reference_by_name(const char *name)
@@ -109,7 +111,7 @@ static const unsigned char *commit_graft_sha1_access(size_t index, void *table)
 	return commit_graft_table[index]->oid.hash;
 }
 
-static int commit_graft_pos(struct repository *r, const unsigned char *sha1)
+int commit_graft_pos(struct repository *r, const unsigned char *sha1)
 {
 	return sha1_pos(sha1, r->parsed_objects->grafts,
 			r->parsed_objects->grafts_nr,
@@ -244,19 +246,6 @@ int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 	return ret;
 }
 
-int unregister_shallow(const struct object_id *oid)
-{
-	int pos = commit_graft_pos(the_repository, oid->hash);
-	if (pos < 0)
-		return -1;
-	if (pos + 1 < the_repository->parsed_objects->grafts_nr)
-		MOVE_ARRAY(the_repository->parsed_objects->grafts + pos,
-			   the_repository->parsed_objects->grafts + pos + 1,
-			   the_repository->parsed_objects->grafts_nr - pos - 1);
-	the_repository->parsed_objects->grafts_nr--;
-	return 0;
-}
-
 struct commit_buffer {
 	void *buffer;
 	unsigned long size;
@@ -350,7 +339,7 @@ struct tree *repo_get_commit_tree(struct repository *r,
 	if (commit->maybe_tree || !commit->object.parsed)
 		return commit->maybe_tree;
 
-	if (commit->graph_pos != COMMIT_NOT_FROM_GRAPH)
+	if (commit_graph_position(commit) != COMMIT_NOT_FROM_GRAPH)
 		return get_commit_tree_in_graph(r, commit);
 
 	return NULL;
@@ -358,14 +347,15 @@ struct tree *repo_get_commit_tree(struct repository *r,
 
 struct object_id *get_commit_tree_oid(const struct commit *commit)
 {
-	return &get_commit_tree(commit)->object.oid;
+	struct tree *tree = get_commit_tree(commit);
+	return tree ? &tree->object.oid : NULL;
 }
 
 void release_commit_memory(struct parsed_object_pool *pool, struct commit *c)
 {
 	set_commit_tree(c, NULL);
-	c->index = 0;
 	free_commit_buffer(pool, c);
+	c->index = 0;
 	free_commit_list(c->parents);
 
 	c->object.parsed = 0;
@@ -400,10 +390,22 @@ int parse_commit_buffer(struct repository *r, struct commit *item, const void *b
 	struct commit_graft *graft;
 	const int tree_entry_len = the_hash_algo->hexsz + 5;
 	const int parent_entry_len = the_hash_algo->hexsz + 7;
+	struct tree *tree;
 
 	if (item->object.parsed)
 		return 0;
-	item->object.parsed = 1;
+
+	if (item->parents) {
+		/*
+		 * Presumably this is leftover from an earlier failed parse;
+		 * clear it out in preparation for us re-parsing (we'll hit the
+		 * same error, but that's good, since it lets our caller know
+		 * the result cannot be trusted.
+		 */
+		free_commit_list(item->parents);
+		item->parents = NULL;
+	}
+
 	tail += size;
 	if (tail <= bufptr + tree_entry_len + 1 || memcmp(bufptr, "tree ", 5) ||
 			bufptr[tree_entry_len] != '\n')
@@ -411,11 +413,18 @@ int parse_commit_buffer(struct repository *r, struct commit *item, const void *b
 	if (get_oid_hex(bufptr + 5, &parent) < 0)
 		return error("bad tree pointer in commit %s",
 			     oid_to_hex(&item->object.oid));
-	set_commit_tree(item, lookup_tree(r, &parent));
+	tree = lookup_tree(r, &parent);
+	if (!tree)
+		return error("bad tree pointer %s in commit %s",
+			     oid_to_hex(&parent),
+			     oid_to_hex(&item->object.oid));
+	set_commit_tree(item, tree);
 	bufptr += tree_entry_len + 1; /* "tree " + "hex sha1" + "\n" */
 	pptr = &item->parents;
 
 	graft = lookup_commit_graft(r, &item->object.oid);
+	if (graft)
+		r->parsed_objects->substituted_parent = 1;
 	while (bufptr + parent_entry_len < tail && !memcmp(bufptr, "parent ", 7)) {
 		struct commit *new_parent;
 
@@ -431,8 +440,11 @@ int parse_commit_buffer(struct repository *r, struct commit *item, const void *b
 		if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 			continue;
 		new_parent = lookup_commit(r, &parent);
-		if (new_parent)
-			pptr = &commit_list_insert(new_parent, pptr)->next;
+		if (!new_parent)
+			return error("bad parent %s in commit %s",
+				     oid_to_hex(&parent),
+				     oid_to_hex(&item->object.oid));
+		pptr = &commit_list_insert(new_parent, pptr)->next;
 	}
 	if (graft) {
 		int i;
@@ -441,7 +453,9 @@ int parse_commit_buffer(struct repository *r, struct commit *item, const void *b
 			new_parent = lookup_commit(r,
 						   &graft->parent[i]);
 			if (!new_parent)
-				continue;
+				return error("bad graft parent %s in commit %s",
+					     oid_to_hex(&graft->parent[i]),
+					     oid_to_hex(&item->object.oid));
 			pptr = &commit_list_insert(new_parent, pptr)->next;
 		}
 	}
@@ -450,6 +464,7 @@ int parse_commit_buffer(struct repository *r, struct commit *item, const void *b
 	if (check_graph)
 		load_commit_graph_info(r, item);
 
+	item->object.parsed = 1;
 	return 0;
 }
 
@@ -716,11 +731,13 @@ int compare_commits_by_author_date(const void *a_, const void *b_,
 int compare_commits_by_gen_then_commit_date(const void *a_, const void *b_, void *unused)
 {
 	const struct commit *a = a_, *b = b_;
+	const uint32_t generation_a = commit_graph_generation(a),
+		       generation_b = commit_graph_generation(b);
 
 	/* newer commits first */
-	if (a->generation < b->generation)
+	if (generation_a < generation_b)
 		return 1;
-	else if (a->generation > b->generation)
+	else if (generation_a > generation_b)
 		return -1;
 
 	/* use date as a heuristic when generations are equal */
@@ -902,12 +919,22 @@ struct commit *get_fork_point(const char *refname, struct commit *commit)
 	struct commit_list *bases;
 	int i;
 	struct commit *ret = NULL;
+	char *full_refname;
+
+	switch (dwim_ref(refname, strlen(refname), &oid, &full_refname, 0)) {
+	case 0:
+		die("No such ref: '%s'", refname);
+	case 1:
+		break; /* good */
+	default:
+		die("Ambiguous refname: '%s'", refname);
+	}
 
 	memset(&revs, 0, sizeof(revs));
 	revs.initial = 1;
-	for_each_reflog_ent(refname, collect_one_reflog_ent, &revs);
+	for_each_reflog_ent(full_refname, collect_one_reflog_ent, &revs);
 
-	if (!revs.nr && !get_oid(refname, &oid))
+	if (!revs.nr)
 		add_one_commit(&oid, &revs);
 
 	for (i = 0; i < revs.nr; i++)
@@ -933,17 +960,26 @@ struct commit *get_fork_point(const char *refname, struct commit *commit)
 
 cleanup_return:
 	free_commit_list(bases);
+	free(full_refname);
 	return ret;
 }
 
-static const char gpg_sig_header[] = "gpgsig";
-static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
+/*
+ * Indexed by hash algorithm identifier.
+ */
+static const char *gpg_sig_headers[] = {
+	NULL,
+	"gpgsig",
+	"gpgsig-sha256",
+};
 
 static int do_sign_commit(struct strbuf *buf, const char *keyid)
 {
 	struct strbuf sig = STRBUF_INIT;
 	int inspos, copypos;
 	const char *eoh;
+	const char *gpg_sig_header = gpg_sig_headers[hash_algo_by_ptr(the_hash_algo)];
+	int gpg_sig_header_len = strlen(gpg_sig_header);
 
 	/* find the end of the header */
 	eoh = strstr(buf->buf, "\n\n");
@@ -968,7 +1004,7 @@ static int do_sign_commit(struct strbuf *buf, const char *keyid)
 			strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
 			inspos += gpg_sig_header_len;
 		}
-		strbuf_insert(buf, inspos++, " ", 1);
+		strbuf_insertstr(buf, inspos++, " ");
 		strbuf_insert(buf, inspos, bol, len);
 		inspos += len;
 		copypos += len;
@@ -985,6 +1021,8 @@ int parse_signed_commit(const struct commit *commit,
 	const char *buffer = get_commit_buffer(commit, &size);
 	int in_signature, saw_signature = -1;
 	const char *line, *tail;
+	const char *gpg_sig_header = gpg_sig_headers[hash_algo_by_ptr(the_hash_algo)];
+	int gpg_sig_header_len = strlen(gpg_sig_header);
 
 	line = buffer;
 	tail = buffer + size;
@@ -1031,11 +1069,17 @@ int remove_signature(struct strbuf *buf)
 
 		if (in_signature && line[0] == ' ')
 			sig_end = next;
-		else if (starts_with(line, gpg_sig_header) &&
-			 line[gpg_sig_header_len] == ' ') {
-			sig_start = line;
-			sig_end = next;
-			in_signature = 1;
+		else if (starts_with(line, "gpgsig")) {
+			int i;
+			for (i = 1; i < GIT_HASH_NALGOS; i++) {
+				const char *p;
+				if (skip_prefix(line, gpg_sig_headers[i], &p) &&
+				    *p == ' ') {
+					sig_start = line;
+					sig_end = next;
+					in_signature = 1;
+				}
+			}
 		} else {
 			if (*line == '\n')
 				/* dump the whole remainder of the buffer */
@@ -1111,21 +1155,23 @@ int check_commit_signature(const struct commit *commit, struct signature_check *
 	return ret;
 }
 
-void verify_merge_signature(struct commit *commit, int verbosity)
+void verify_merge_signature(struct commit *commit, int verbosity,
+			    int check_trust)
 {
 	char hex[GIT_MAX_HEXSZ + 1];
 	struct signature_check signature_check;
+	int ret;
 	memset(&signature_check, 0, sizeof(signature_check));
 
-	check_commit_signature(commit, &signature_check);
+	ret = check_commit_signature(commit, &signature_check);
 
 	find_unique_abbrev_r(hex, &commit->object.oid, DEFAULT_ABBREV);
 	switch (signature_check.result) {
 	case 'G':
+		if (ret || (check_trust && signature_check.trust_level < TRUST_MARGINAL))
+			die(_("Commit %s has an untrusted GPG signature, "
+			      "allegedly by %s."), hex, signature_check.signer);
 		break;
-	case 'U':
-		die(_("Commit %s has an untrusted GPG signature, "
-		      "allegedly by %s."), hex, signature_check.signer);
 	case 'B':
 		die(_("Commit %s has a bad GPG signature "
 		      "allegedly by %s."), hex, signature_check.signer);
@@ -1270,8 +1316,8 @@ int commit_tree(const char *msg, size_t msg_len, const struct object_id *tree,
 	int result;
 
 	append_merge_tag_headers(parents, &tail);
-	result = commit_tree_extended(msg, msg_len, tree, parents, ret,
-				      author, sign_commit, extra);
+	result = commit_tree_extended(msg, msg_len, tree, parents, ret, author,
+				      NULL, sign_commit, extra);
 	free_commit_extra_headers(extra);
 	return result;
 }
@@ -1394,7 +1440,8 @@ N_("Warning: commit message did not conform to UTF-8.\n"
 int commit_tree_extended(const char *msg, size_t msg_len,
 			 const struct object_id *tree,
 			 struct commit_list *parents, struct object_id *ret,
-			 const char *author, const char *sign_commit,
+			 const char *author, const char *committer,
+			 const char *sign_commit,
 			 struct commit_extra_header *extra)
 {
 	int result;
@@ -1427,7 +1474,9 @@ int commit_tree_extended(const char *msg, size_t msg_len,
 	if (!author)
 		author = git_author_info(IDENT_STRICT);
 	strbuf_addf(&buffer, "author %s\n", author);
-	strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
+	if (!committer)
+		committer = git_committer_info(IDENT_STRICT);
+	strbuf_addf(&buffer, "committer %s\n", committer);
 	if (!encoding_is_utf8)
 		strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
 
@@ -1580,3 +1629,26 @@ size_t ignore_non_trailer(const char *buf, size_t len)
 	}
 	return boc ? len - boc : len - cutoff;
 }
+
+int run_commit_hook(int editor_is_used, const char *index_file,
+		    const char *name, ...)
+{
+	struct strvec hook_env = STRVEC_INIT;
+	va_list args;
+	int ret;
+
+	strvec_pushf(&hook_env, "GIT_INDEX_FILE=%s", index_file);
+
+	/*
+	 * Let the hook know that no editor will be launched.
+	 */
+	if (!editor_is_used)
+		strvec_push(&hook_env, "GIT_EDITOR=:");
+
+	va_start(args, name);
+	ret = run_hook_ve(hook_env.v, name, args);
+	va_end(args);
+	strvec_clear(&hook_env);
+
+	return ret;
+}