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, 59 insertions, 30 deletions

diff --git a/third_party/git/tree-walk.c b/third_party/git/tree-walk.c
index c20b62f49e47..0160294712b4 100644
--- a/third_party/git/tree-walk.c
+++ b/third_party/git/tree-walk.c
@@ -1,6 +1,5 @@
 #include "cache.h"
 #include "tree-walk.h"
-#include "unpack-trees.h"
 #include "dir.h"
 #include "object-store.h"
 #include "tree.h"
@@ -170,40 +169,61 @@ int tree_entry_gently(struct tree_desc *desc, struct name_entry *entry)
 
 void setup_traverse_info(struct traverse_info *info, const char *base)
 {
-	int pathlen = strlen(base);
+	size_t pathlen = strlen(base);
 	static struct traverse_info dummy;
 
 	memset(info, 0, sizeof(*info));
 	if (pathlen && base[pathlen-1] == '/')
 		pathlen--;
 	info->pathlen = pathlen ? pathlen + 1 : 0;
-	info->name.path = base;
-	info->name.pathlen = pathlen;
-	if (pathlen) {
-		hashcpy(info->name.oid.hash, (const unsigned char *)base + pathlen + 1);
+	info->name = base;
+	info->namelen = pathlen;
+	if (pathlen)
 		info->prev = &dummy;
-	}
 }
 
-char *make_traverse_path(char *path, const struct traverse_info *info, const struct name_entry *n)
+char *make_traverse_path(char *path, size_t pathlen,
+			 const struct traverse_info *info,
+			 const char *name, size_t namelen)
 {
-	int len = tree_entry_len(n);
-	int pathlen = info->pathlen;
+	/* Always points to the end of the name we're about to add */
+	size_t pos = st_add(info->pathlen, namelen);
+
+	if (pos >= pathlen)
+		BUG("too small buffer passed to make_traverse_path");
 
-	path[pathlen + len] = 0;
+	path[pos] = 0;
 	for (;;) {
-		memcpy(path + pathlen, n->path, len);
-		if (!pathlen)
+		if (pos < namelen)
+			BUG("traverse_info pathlen does not match strings");
+		pos -= namelen;
+		memcpy(path + pos, name, namelen);
+
+		if (!pos)
 			break;
-		path[--pathlen] = '/';
-		n = &info->name;
-		len = tree_entry_len(n);
+		path[--pos] = '/';
+
+		if (!info)
+			BUG("traverse_info ran out of list items");
+		name = info->name;
+		namelen = info->namelen;
 		info = info->prev;
-		pathlen -= len;
 	}
 	return path;
 }
 
+void strbuf_make_traverse_path(struct strbuf *out,
+			       const struct traverse_info *info,
+			       const char *name, size_t namelen)
+{
+	size_t len = traverse_path_len(info, namelen);
+
+	strbuf_grow(out, len);
+	make_traverse_path(out->buf + out->len, out->alloc - out->len,
+			   info, name, namelen);
+	strbuf_setlen(out, out->len + len);
+}
+
 struct tree_desc_skip {
 	struct tree_desc_skip *prev;
 	const void *ptr;
@@ -389,24 +409,28 @@ int traverse_trees(struct index_state *istate,
 		   struct traverse_info *info)
 {
 	int error = 0;
-	struct name_entry *entry = xmalloc(n*sizeof(*entry));
+	struct name_entry entry[MAX_TRAVERSE_TREES];
 	int i;
-	struct tree_desc_x *tx = xcalloc(n, sizeof(*tx));
+	struct tree_desc_x tx[ARRAY_SIZE(entry)];
 	struct strbuf base = STRBUF_INIT;
 	int interesting = 1;
 	char *traverse_path;
 
-	for (i = 0; i < n; i++)
+	if (n >= ARRAY_SIZE(entry))
+		BUG("traverse_trees() called with too many trees (%d)", n);
+
+	for (i = 0; i < n; i++) {
 		tx[i].d = t[i];
+		tx[i].skip = NULL;
+	}
 
 	if (info->prev) {
-		strbuf_grow(&base, info->pathlen);
-		make_traverse_path(base.buf, info->prev, &info->name);
-		base.buf[info->pathlen-1] = '/';
-		strbuf_setlen(&base, info->pathlen);
-		traverse_path = xstrndup(base.buf, info->pathlen);
+		strbuf_make_traverse_path(&base, info->prev,
+					  info->name, info->namelen);
+		strbuf_addch(&base, '/');
+		traverse_path = xstrndup(base.buf, base.len);
 	} else {
-		traverse_path = xstrndup(info->name.path, info->pathlen);
+		traverse_path = xstrndup(info->name, info->pathlen);
 	}
 	info->traverse_path = traverse_path;
 	for (;;) {
@@ -486,10 +510,8 @@ int traverse_trees(struct index_state *istate,
 			if (mask & (1ul << i))
 				update_extended_entry(tx + i, entry + i);
 	}
-	free(entry);
 	for (i = 0; i < n; i++)
 		free_extended_entry(tx + i);
-	free(tx);
 	free(traverse_path);
 	info->traverse_path = NULL;
 	strbuf_release(&base);
@@ -829,7 +851,14 @@ static int match_entry(const struct pathspec_item *item,
 	if (matchlen > pathlen) {
 		if (match[pathlen] != '/')
 			return 0;
-		if (!S_ISDIR(entry->mode) && !S_ISGITLINK(entry->mode))
+		/*
+		 * Reject non-directories as partial pathnames, except
+		 * when match is a submodule with a trailing slash and
+		 * nothing else (to handle 'submod/' and 'submod'
+		 * uniformly).
+		 */
+		if (!S_ISDIR(entry->mode) &&
+		    (!S_ISGITLINK(entry->mode) || matchlen > pathlen + 1))
 			return 0;
 	}
 
@@ -1104,7 +1133,7 @@ match_wildcards:
 		 * later on.
 		 * max_depth is ignored but we may consider support it
 		 * in future, see
-		 * https://public-inbox.org/git/7vmxo5l2g4.fsf@alter.siamese.dyndns.org/
+		 * https://lore.kernel.org/git/7vmxo5l2g4.fsf@alter.siamese.dyndns.org/
 		 */
 		if (ps->recursive && S_ISDIR(entry->mode))
 			return entry_interesting;