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

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

third_party/git/cache-tree.c

@@ -5,6 +5,7 @@
 #include "cache-tree.h"
 #include "object-store.h"
 #include "replace-object.h"
+#include "promisor-remote.h"
 
 #ifndef DEBUG_CACHE_TREE
 #define DEBUG_CACHE_TREE 0
@@ -357,7 +358,7 @@ static int update_one(struct cache_tree *it,
 		}
 
 		ce_missing_ok = mode == S_IFGITLINK || missing_ok ||
-			(repository_format_partial_clone &&
+			(has_promisor_remote() &&
 			 ce_skip_worktree(ce));
 		if (is_null_oid(oid) ||
 		    (!ce_missing_ok && !has_object_file(oid))) {
@@ -406,13 +407,15 @@ static int update_one(struct cache_tree *it,
 
 	if (repair) {
 		struct object_id oid;
-		hash_object_file(buffer.buf, buffer.len, tree_type, &oid);
-		if (has_object_file(&oid))
+		hash_object_file(the_hash_algo, buffer.buf, buffer.len,
+				 tree_type, &oid);
+		if (has_object_file_with_flags(&oid, OBJECT_INFO_SKIP_FETCH_OBJECT))
 			oidcpy(&it->oid, &oid);
 		else
 			to_invalidate = 1;
 	} else if (dryrun) {
-		hash_object_file(buffer.buf, buffer.len, tree_type, &it->oid);
+		hash_object_file(the_hash_algo, buffer.buf, buffer.len,
+				 tree_type, &it->oid);
 	} else if (write_object_file(buffer.buf, buffer.len, tree_type,
 				     &it->oid)) {
 		strbuf_release(&buffer);
@@ -608,11 +611,66 @@ static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *pat
 	return it;
 }
 
+static int write_index_as_tree_internal(struct object_id *oid,
+					struct index_state *index_state,
+					int cache_tree_valid,
+					int flags,
+					const char *prefix)
+{
+	if (flags & WRITE_TREE_IGNORE_CACHE_TREE) {
+		cache_tree_free(&index_state->cache_tree);
+		cache_tree_valid = 0;
+	}
+
+	if (!index_state->cache_tree)
+		index_state->cache_tree = cache_tree();
+
+	if (!cache_tree_valid && cache_tree_update(index_state, flags) < 0)
+		return WRITE_TREE_UNMERGED_INDEX;
+
+	if (prefix) {
+		struct cache_tree *subtree;
+		subtree = cache_tree_find(index_state->cache_tree, prefix);
+		if (!subtree)
+			return WRITE_TREE_PREFIX_ERROR;
+		oidcpy(oid, &subtree->oid);
+	}
+	else
+		oidcpy(oid, &index_state->cache_tree->oid);
+
+	return 0;
+}
+
+struct tree* write_in_core_index_as_tree(struct repository *repo) {
+	struct object_id o;
+	int was_valid, ret;
+
+	struct index_state *index_state	= repo->index;
+	was_valid = index_state->cache_tree &&
+		    cache_tree_fully_valid(index_state->cache_tree);
+
+	ret = write_index_as_tree_internal(&o, index_state, was_valid, 0, NULL);
+	if (ret == WRITE_TREE_UNMERGED_INDEX) {
+		int i;
+		fprintf(stderr, "BUG: There are unmerged index entries:\n");
+		for (i = 0; i < index_state->cache_nr; i++) {
+			const struct cache_entry *ce = index_state->cache[i];
+			if (ce_stage(ce))
+				fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
+					(int)ce_namelen(ce), ce->name);
+		}
+		BUG("unmerged index entries when writing inmemory index");
+	}
+
+	return lookup_tree(repo, &index_state->cache_tree->oid);
+}
+
+
 int write_index_as_tree(struct object_id *oid, struct index_state *index_state, const char *index_path, int flags, const char *prefix)
 {
 	int entries, was_valid;
 	struct lock_file lock_file = LOCK_INIT;
-	int ret = 0;
+	int ret;
 
 	hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);
 
@@ -621,18 +679,14 @@ int write_index_as_tree(struct object_id *oid, struct index_state *index_state,
 		ret = WRITE_TREE_UNREADABLE_INDEX;
 		goto out;
 	}
-	if (flags & WRITE_TREE_IGNORE_CACHE_TREE)
-		cache_tree_free(&index_state->cache_tree);
 
-	if (!index_state->cache_tree)
-		index_state->cache_tree = cache_tree();
+	was_valid = !(flags & WRITE_TREE_IGNORE_CACHE_TREE) &&
+		    index_state->cache_tree &&
+		    cache_tree_fully_valid(index_state->cache_tree);
 
-	was_valid = cache_tree_fully_valid(index_state->cache_tree);
-	if (!was_valid) {
-		if (cache_tree_update(index_state, flags) < 0) {
-			ret = WRITE_TREE_UNMERGED_INDEX;
-			goto out;
-		}
+	ret = write_index_as_tree_internal(oid, index_state, was_valid, flags,
+					   prefix);
+	if (!ret && !was_valid) {
 		write_locked_index(index_state, &lock_file, COMMIT_LOCK);
 		/* Not being able to write is fine -- we are only interested
 		 * in updating the cache-tree part, and if the next caller
@@ -642,18 +696,6 @@ int write_index_as_tree(struct object_id *oid, struct index_state *index_state,
 		 */
 	}
 
-	if (prefix) {
-		struct cache_tree *subtree;
-		subtree = cache_tree_find(index_state->cache_tree, prefix);
-		if (!subtree) {
-			ret = WRITE_TREE_PREFIX_ERROR;
-			goto out;
-		}
-		oidcpy(oid, &subtree->oid);
-	}
-	else
-		oidcpy(oid, &index_state->cache_tree->oid);
-
 out:
 	rollback_lock_file(&lock_file);
 	return ret;
@@ -713,7 +755,7 @@ static struct cache_tree *find_cache_tree_from_traversal(struct cache_tree *root
 	if (!info->prev)
 		return root;
 	our_parent = find_cache_tree_from_traversal(root, info->prev);
-	return cache_tree_find(our_parent, info->name.path);
+	return cache_tree_find(our_parent, info->name);
 }
 
 int cache_tree_matches_traversal(struct cache_tree *root,
@@ -786,9 +828,10 @@ static void verify_one(struct repository *r,
 			i++;
 		}
 		strbuf_addf(&tree_buf, "%o %.*s%c", mode, entlen, name, '\0');
-		strbuf_add(&tree_buf, oid->hash, the_hash_algo->rawsz);
+		strbuf_add(&tree_buf, oid->hash, r->hash_algo->rawsz);
 	}
-	hash_object_file(tree_buf.buf, tree_buf.len, tree_type, &new_oid);
+	hash_object_file(r->hash_algo, tree_buf.buf, tree_buf.len, tree_type,
+			 &new_oid);
 	if (!oideq(&new_oid, &it->oid))
 		BUG("cache-tree for path %.*s does not match. "
 		    "Expected %s got %s", len, path->buf,