xz: Clarify a comment

diff --git a/src/xz/coder.c b/src/xz/coder.c
index 1ea97244fddcbe25441dbd320be8d68a80f5f892..f3e9093ba6eb1390381cb9d278d9b953b7768975 100644 (file)
--- a/src/xz/coder.c
+++ b/src/xz/coder.c
@@ -383,7 +383,9 @@ coder_set_compression_settings(void)
                                "the LZMA1 filter"));
 
        // If we are using the .xz format, make sure that there is no LZMA1
-       // filter to prevent LZMA_PROG_ERROR.
+       // filter to prevent LZMA_PROG_ERROR. With the chains from --filtersX
+       // we have already ensured this by calling lzma_str_to_filters()
+       // without setting the flags that would allow non-.xz filters.
        if (opt_format == FORMAT_XZ && filters_used_mask & 1)
                for (size_t i = 0; i < filters_count; ++i)
                        if (default_filters[i].id == LZMA_FILTER_LZMA1)