Merge branch 'ds/sparse-colon-path'

"git show :<path>" learned to work better with the sparse-index
feature.

* ds/sparse-colon-path:
  rev-parse: integrate with sparse index
  object-name: diagnose trees in index properly
  object-name: reject trees found in the index
  show: integrate with the sparse index
  t1092: add compatibility tests for 'git show'

builtin/log.c

@@ -669,6 +669,11 @@ int cmd_show(int argc, const char **argv, const char *prefix)
 	init_log_defaults();
 	git_config(git_log_config, NULL);
 
+	if (the_repository->gitdir) {
+		prepare_repo_settings(the_repository);
+		the_repository->settings.command_requires_full_index = 0;
+	}
+
 	memset(&match_all, 0, sizeof(match_all));
 	repo_init_revisions(the_repository, &rev, prefix);
 	git_config(grep_config, &rev.grep_filter);