diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index 425a577..9f31837 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -379,7 +379,6 @@
 	repo_init_revisions(the_repository, &revs, prefix);
 	revs.abbrev = DEFAULT_ABBREV;
 	revs.commit_format = CMIT_FMT_UNSPECIFIED;
-	revs.do_not_die_on_missing_tree = 1;
 
 	/*
 	 * Scan the argument list before invoking setup_revisions(), so that we
@@ -409,6 +408,9 @@
 		}
 	}
 
+	if (arg_missing_action)
+		revs.do_not_die_on_missing_tree = 1;
+
 	argc = setup_revisions(argc, argv, &revs, &s_r_opt);
 
 	memset(&info, 0, sizeof(info));
diff --git a/commit.c b/commit.c
index a9e7464..8fa1883 100644
--- a/commit.c
+++ b/commit.c
@@ -351,10 +351,10 @@
 	if (commit->maybe_tree || !commit->object.parsed)
 		return commit->maybe_tree;
 
-	if (commit->graph_pos == COMMIT_NOT_FROM_GRAPH)
-		BUG("commit has NULL tree, but was not loaded from commit-graph");
+	if (commit->graph_pos != COMMIT_NOT_FROM_GRAPH)
+		return get_commit_tree_in_graph(r, commit);
 
-	return get_commit_tree_in_graph(r, commit);
+	return NULL;
 }
 
 struct object_id *get_commit_tree_oid(const struct commit *commit)
diff --git a/list-objects.c b/list-objects.c
index dc77361..b5651dd 100644
--- a/list-objects.c
+++ b/list-objects.c
@@ -125,6 +125,11 @@
 
 		if (S_ISDIR(entry.mode)) {
 			struct tree *t = lookup_tree(ctx->revs->repo, &entry.oid);
+			if (!t) {
+				die(_("entry '%s' in tree %s has tree mode, "
+				      "but is not a tree"),
+				    entry.path, oid_to_hex(&tree->object.oid));
+			}
 			t->object.flags |= NOT_USER_GIVEN;
 			process_tree(ctx, t, base, entry.path);
 		}
@@ -133,6 +138,11 @@
 					base, entry.path);
 		else {
 			struct blob *b = lookup_blob(ctx->revs->repo, &entry.oid);
+			if (!b) {
+				die(_("entry '%s' in tree %s has blob mode, "
+				      "but is not a blob"),
+				    entry.path, oid_to_hex(&tree->object.oid));
+			}
 			b->object.flags |= NOT_USER_GIVEN;
 			process_blob(ctx, b, base, entry.path);
 		}
@@ -364,6 +374,9 @@
 			struct tree *tree = get_commit_tree(commit);
 			tree->object.flags |= NOT_USER_GIVEN;
 			add_pending_tree(ctx->revs, tree);
+		} else if (commit->object.parsed) {
+			die(_("unable to load root tree for commit %s"),
+			      oid_to_hex(&commit->object.oid));
 		}
 		ctx->show_commit(commit, ctx->show_data);
 
diff --git a/t/t1007-hash-object.sh b/t/t1007-hash-object.sh
index a377530..7099d33 100755
--- a/t/t1007-hash-object.sh
+++ b/t/t1007-hash-object.sh
@@ -199,10 +199,6 @@
 	test_i18ngrep "too-short tree object" err
 '
 
-hex2oct() {
-    perl -ne 'printf "\\%03o", hex for /../g'
-}
-
 test_expect_success 'malformed mode in tree' '
 	hex_sha1=$(echo foo | git hash-object --stdin -w) &&
 	bin_sha1=$(echo $hex_sha1 | hex2oct) &&
diff --git a/t/t1450-fsck.sh b/t/t1450-fsck.sh
index 49f08d5..0f268a3 100755
--- a/t/t1450-fsck.sh
+++ b/t/t1450-fsck.sh
@@ -256,10 +256,6 @@
 	test_i18ngrep ! "fatal: empty filename in tree entry" out
 '
 
-hex2oct() {
-	perl -ne 'printf "\\%03o", hex for /../g'
-}
-
 test_expect_success 'tree entry with type mismatch' '
 	test_when_finished "remove_object \$blob" &&
 	test_when_finished "remove_object \$tree" &&
diff --git a/t/t5601-clone.sh b/t/t5601-clone.sh
index 23854ca..de9d99c 100755
--- a/t/t5601-clone.sh
+++ b/t/t5601-clone.sh
@@ -611,10 +611,6 @@
 	git -C replay.git index-pack -v --stdin <tmp.pack
 '
 
-hex2oct () {
-	perl -ne 'printf "\\%03o", hex for /../g'
-}
-
 test_expect_success 'clone on case-insensitive fs' '
 	git init icasefs &&
 	(
diff --git a/t/t6102-rev-list-unexpected-objects.sh b/t/t6102-rev-list-unexpected-objects.sh
new file mode 100755
index 0000000..28611c9
--- /dev/null
+++ b/t/t6102-rev-list-unexpected-objects.sh
@@ -0,0 +1,127 @@
+#!/bin/sh
+
+test_description='git rev-list should handle unexpected object types'
+
+. ./test-lib.sh
+
+test_expect_success 'setup well-formed objects' '
+	blob="$(printf "foo" | git hash-object -w --stdin)" &&
+	tree="$(printf "100644 blob $blob\tfoo" | git mktree)" &&
+	commit="$(git commit-tree $tree -m "first commit")" &&
+	git cat-file commit $commit >good-commit
+'
+
+test_expect_success 'setup unexpected non-blob entry' '
+	printf "100644 foo\0$(echo $tree | hex2oct)" >broken-tree &&
+	broken_tree="$(git hash-object -w --literally -t tree broken-tree)"
+'
+
+test_expect_failure 'traverse unexpected non-blob entry (lone)' '
+	test_must_fail git rev-list --objects $broken_tree
+'
+
+test_expect_success 'traverse unexpected non-blob entry (seen)' '
+	test_must_fail git rev-list --objects $tree $broken_tree >output 2>&1 &&
+	test_i18ngrep "is not a blob" output
+'
+
+test_expect_success 'setup unexpected non-tree entry' '
+	printf "40000 foo\0$(echo $blob | hex2oct)" >broken-tree &&
+	broken_tree="$(git hash-object -w --literally -t tree broken-tree)"
+'
+
+test_expect_success 'traverse unexpected non-tree entry (lone)' '
+	test_must_fail git rev-list --objects $broken_tree
+'
+
+test_expect_success 'traverse unexpected non-tree entry (seen)' '
+	test_must_fail git rev-list --objects $blob $broken_tree >output 2>&1 &&
+	test_i18ngrep "is not a tree" output
+'
+
+test_expect_success 'setup unexpected non-commit parent' '
+	sed "/^author/ { h; s/.*/parent $blob/; G; }" <good-commit \
+		>broken-commit &&
+	broken_commit="$(git hash-object -w --literally -t commit \
+		broken-commit)"
+'
+
+test_expect_success 'traverse unexpected non-commit parent (lone)' '
+	test_must_fail git rev-list --objects $broken_commit >output 2>&1 &&
+	test_i18ngrep "not a commit" output
+'
+
+test_expect_success 'traverse unexpected non-commit parent (seen)' '
+	test_must_fail git rev-list --objects $commit $broken_commit \
+		>output 2>&1 &&
+	test_i18ngrep "not a commit" output
+'
+
+test_expect_success 'setup unexpected non-tree root' '
+	sed -e "s/$tree/$blob/" <good-commit >broken-commit &&
+	broken_commit="$(git hash-object -w --literally -t commit \
+		broken-commit)"
+'
+
+test_expect_success 'traverse unexpected non-tree root (lone)' '
+	test_must_fail git rev-list --objects $broken_commit
+'
+
+test_expect_success 'traverse unexpected non-tree root (seen)' '
+	test_must_fail git rev-list --objects $blob $broken_commit \
+		>output 2>&1 &&
+	test_i18ngrep "not a tree" output
+'
+
+test_expect_success 'setup unexpected non-commit tag' '
+	git tag -a -m "tagged commit" tag $commit &&
+	git cat-file tag tag >good-tag &&
+	test_when_finished "git tag -d tag" &&
+	sed -e "s/$commit/$blob/" <good-tag >broken-tag &&
+	tag=$(git hash-object -w --literally -t tag broken-tag)
+'
+
+test_expect_success 'traverse unexpected non-commit tag (lone)' '
+	test_must_fail git rev-list --objects $tag
+'
+
+test_expect_success 'traverse unexpected non-commit tag (seen)' '
+	test_must_fail git rev-list --objects $blob $tag >output 2>&1 &&
+	test_i18ngrep "not a commit" output
+'
+
+test_expect_success 'setup unexpected non-tree tag' '
+	git tag -a -m "tagged tree" tag $tree &&
+	git cat-file tag tag >good-tag &&
+	test_when_finished "git tag -d tag" &&
+	sed -e "s/$tree/$blob/" <good-tag >broken-tag &&
+	tag=$(git hash-object -w --literally -t tag broken-tag)
+'
+
+test_expect_success 'traverse unexpected non-tree tag (lone)' '
+	test_must_fail git rev-list --objects $tag
+'
+
+test_expect_success 'traverse unexpected non-tree tag (seen)' '
+	test_must_fail git rev-list --objects $blob $tag >output 2>&1 &&
+	test_i18ngrep "not a tree" output
+'
+
+test_expect_success 'setup unexpected non-blob tag' '
+	git tag -a -m "tagged blob" tag $blob &&
+	git cat-file tag tag >good-tag &&
+	test_when_finished "git tag -d tag" &&
+	sed -e "s/$blob/$commit/" <good-tag >broken-tag &&
+	tag=$(git hash-object -w --literally -t tag broken-tag)
+'
+
+test_expect_failure 'traverse unexpected non-blob tag (lone)' '
+	test_must_fail git rev-list --objects $tag
+'
+
+test_expect_success 'traverse unexpected non-blob tag (seen)' '
+	test_must_fail git rev-list --objects $commit $tag >output 2>&1 &&
+	test_i18ngrep "not a blob" output
+'
+
+test_done
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 788ea1f..8270de7 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -1239,6 +1239,12 @@
 	'
 }
 
+# Converts base-16 data into base-8. The output is given as a sequence of
+# escaped octals, suitable for consumption by 'printf'.
+hex2oct () {
+	perl -ne 'printf "\\%03o", hex for /../g'
+}
+
 # Set the hash algorithm in use to $1.  Only useful when testing the testsuite.
 test_set_hash () {
 	test_hash_algo="$1"