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, 62 insertions, 32 deletions

diff --git a/third_party/git/commit-reach.c b/third_party/git/commit-reach.c
index 3ea174788a4f..50175b159e70 100644
--- a/third_party/git/commit-reach.c
+++ b/third_party/git/commit-reach.c
@@ -10,7 +10,6 @@
 #include "commit-reach.h"
 
 /* Remember to update object flag allocation in object.h */
-#define REACHABLE       (1u<<15)
 #define PARENT1		(1u<<16)
 #define PARENT2		(1u<<17)
 #define STALE		(1u<<18)
@@ -59,14 +58,15 @@ static struct commit_list *paint_down_to_common(struct repository *r,
 		struct commit *commit = prio_queue_get(&queue);
 		struct commit_list *parents;
 		int flags;
+		uint32_t generation = commit_graph_generation(commit);
 
-		if (min_generation && commit->generation > last_gen)
+		if (min_generation && generation > last_gen)
 			BUG("bad generation skip %8x > %8x at %s",
-			    commit->generation, last_gen,
+			    generation, last_gen,
 			    oid_to_hex(&commit->object.oid));
-		last_gen = commit->generation;
+		last_gen = generation;
 
-		if (commit->generation < min_generation)
+		if (generation < min_generation)
 			break;
 
 		flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
@@ -177,18 +177,20 @@ static int remove_redundant(struct repository *r, struct commit **array, int cnt
 		repo_parse_commit(r, array[i]);
 	for (i = 0; i < cnt; i++) {
 		struct commit_list *common;
-		uint32_t min_generation = array[i]->generation;
+		uint32_t min_generation = commit_graph_generation(array[i]);
 
 		if (redundant[i])
 			continue;
 		for (j = filled = 0; j < cnt; j++) {
+			uint32_t curr_generation;
 			if (i == j || redundant[j])
 				continue;
 			filled_index[filled] = j;
 			work[filled++] = array[j];
 
-			if (array[j]->generation < min_generation)
-				min_generation = array[j]->generation;
+			curr_generation = commit_graph_generation(array[j]);
+			if (curr_generation < min_generation)
+				min_generation = curr_generation;
 		}
 		common = paint_down_to_common(r, array[i], filled,
 					      work, min_generation);
@@ -284,7 +286,9 @@ struct commit_list *repo_get_merge_bases(struct repository *r,
 /*
  * Is "commit" a descendant of one of the elements on the "with_commit" list?
  */
-int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
+int repo_is_descendant_of(struct repository *r,
+			  struct commit *commit,
+			  struct commit_list *with_commit)
 {
 	if (!with_commit)
 		return 1;
@@ -302,7 +306,7 @@ int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 
 			other = with_commit->item;
 			with_commit = with_commit->next;
-			if (in_merge_bases(other, commit))
+			if (repo_in_merge_bases_many(r, other, 1, &commit))
 				return 1;
 		}
 		return 0;
@@ -317,23 +321,26 @@ int repo_in_merge_bases_many(struct repository *r, struct commit *commit,
 {
 	struct commit_list *bases;
 	int ret = 0, i;
-	uint32_t min_generation = GENERATION_NUMBER_INFINITY;
+	uint32_t generation, max_generation = GENERATION_NUMBER_ZERO;
 
 	if (repo_parse_commit(r, commit))
 		return ret;
 	for (i = 0; i < nr_reference; i++) {
 		if (repo_parse_commit(r, reference[i]))
 			return ret;
-		if (reference[i]->generation < min_generation)
-			min_generation = reference[i]->generation;
+
+		generation = commit_graph_generation(reference[i]);
+		if (generation > max_generation)
+			max_generation = generation;
 	}
 
-	if (commit->generation > min_generation)
+	generation = commit_graph_generation(commit);
+	if (generation > max_generation)
 		return ret;
 
 	bases = paint_down_to_common(r, commit,
 				     nr_reference, reference,
-				     commit->generation);
+				     generation);
 	if (commit->object.flags & PARENT2)
 		ret = 1;
 	clear_commit_marks(commit, all_flags);
@@ -349,7 +356,15 @@ int repo_in_merge_bases(struct repository *r,
 			struct commit *commit,
 			struct commit *reference)
 {
-	return repo_in_merge_bases_many(r, commit, 1, &reference);
+	int res;
+	struct commit_list *list = NULL;
+	struct commit_list **next = &list;
+
+	next = commit_list_append(commit, next);
+	res = repo_is_descendant_of(r, reference, list);
+	free_commit_list(list);
+
+	return res;
 }
 
 struct commit_list *reduce_heads(struct commit_list *heads)
@@ -397,6 +412,7 @@ int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
 	struct object *o;
 	struct commit *old_commit, *new_commit;
 	struct commit_list *old_commit_list = NULL;
+	int ret;
 
 	/*
 	 * Both new_commit and old_commit must be commit-ish and new_commit is descendant of
@@ -418,7 +434,10 @@ int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
 		return 0;
 
 	commit_list_insert(old_commit, &old_commit_list);
-	return is_descendant_of(new_commit, old_commit_list);
+	ret = repo_is_descendant_of(the_repository,
+				    new_commit, old_commit_list);
+	free_commit_list(old_commit_list);
+	return ret;
 }
 
 /*
@@ -468,7 +487,7 @@ static enum contains_result contains_test(struct commit *candidate,
 	/* Otherwise, we don't know; prepare to recurse */
 	parse_commit_or_die(candidate);
 
-	if (candidate->generation < cutoff)
+	if (commit_graph_generation(candidate) < cutoff)
 		return CONTAINS_NO;
 
 	return CONTAINS_UNKNOWN;
@@ -491,10 +510,12 @@ static enum contains_result contains_tag_algo(struct commit *candidate,
 	const struct commit_list *p;
 
 	for (p = want; p; p = p->next) {
+		uint32_t generation;
 		struct commit *c = p->item;
 		load_commit_graph_info(the_repository, c);
-		if (c->generation < cutoff)
-			cutoff = c->generation;
+		generation = commit_graph_generation(c);
+		if (generation < cutoff)
+			cutoff = generation;
 	}
 
 	result = contains_test(candidate, want, cache, cutoff);
@@ -537,7 +558,7 @@ int commit_contains(struct ref_filter *filter, struct commit *commit,
 {
 	if (filter->with_commit_tag_algo)
 		return contains_tag_algo(commit, list, cache) == CONTAINS_YES;
-	return is_descendant_of(commit, list);
+	return repo_is_descendant_of(the_repository, commit, list);
 }
 
 static int compare_commits_by_gen(const void *_a, const void *_b)
@@ -545,9 +566,12 @@ static int compare_commits_by_gen(const void *_a, const void *_b)
 	const struct commit *a = *(const struct commit * const *)_a;
 	const struct commit *b = *(const struct commit * const *)_b;
 
-	if (a->generation < b->generation)
+	uint32_t generation_a = commit_graph_generation(a);
+	uint32_t generation_b = commit_graph_generation(b);
+
+	if (generation_a < generation_b)
 		return -1;
-	if (a->generation > b->generation)
+	if (generation_a > generation_b)
 		return 1;
 	return 0;
 }
@@ -586,7 +610,7 @@ int can_all_from_reach_with_flag(struct object_array *from,
 
 		list[nr_commits] = (struct commit *)from_one;
 		if (parse_commit(list[nr_commits]) ||
-		    list[nr_commits]->generation < min_generation) {
+		    commit_graph_generation(list[nr_commits]) < min_generation) {
 			result = 0;
 			goto cleanup;
 		}
@@ -622,7 +646,7 @@ int can_all_from_reach_with_flag(struct object_array *from,
 
 					if (parse_commit(parent->item) ||
 					    parent->item->date < min_commit_date ||
-					    parent->item->generation < min_generation)
+					    commit_graph_generation(parent->item) < min_generation)
 						continue;
 
 					commit_list_insert(parent->item, &stack);
@@ -663,11 +687,13 @@ int can_all_from_reach(struct commit_list *from, struct commit_list *to,
 		add_object_array(&from_iter->item->object, NULL, &from_objs);
 
 		if (!parse_commit(from_iter->item)) {
+			uint32_t generation;
 			if (from_iter->item->date < min_commit_date)
 				min_commit_date = from_iter->item->date;
 
-			if (from_iter->item->generation < min_generation)
-				min_generation = from_iter->item->generation;
+			generation = commit_graph_generation(from_iter->item);
+			if (generation < min_generation)
+				min_generation = generation;
 		}
 
 		from_iter = from_iter->next;
@@ -675,11 +701,13 @@ int can_all_from_reach(struct commit_list *from, struct commit_list *to,
 
 	while (to_iter) {
 		if (!parse_commit(to_iter->item)) {
+			uint32_t generation;
 			if (to_iter->item->date < min_commit_date)
 				min_commit_date = to_iter->item->date;
 
-			if (to_iter->item->generation < min_generation)
-				min_generation = to_iter->item->generation;
+			generation = commit_graph_generation(to_iter->item);
+			if (generation < min_generation)
+				min_generation = generation;
 		}
 
 		to_iter->item->object.flags |= PARENT2;
@@ -719,11 +747,13 @@ struct commit_list *get_reachable_subset(struct commit **from, int nr_from,
 	struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
 
 	for (item = to; item < to_last; item++) {
+		uint32_t generation;
 		struct commit *c = *item;
 
 		parse_commit(c);
-		if (c->generation < min_generation)
-			min_generation = c->generation;
+		generation = commit_graph_generation(c);
+		if (generation < min_generation)
+			min_generation = generation;
 
 		if (!(c->object.flags & PARENT1)) {
 			c->object.flags |= PARENT1;
@@ -756,7 +786,7 @@ struct commit_list *get_reachable_subset(struct commit **from, int nr_from,
 
 			parse_commit(p);
 
-			if (p->generation < min_generation)
+			if (commit_graph_generation(p) < min_generation)
 				continue;
 
 			if (p->object.flags & PARENT2)