osd/scrubber: mark fmt::formatter<..>::format() as const

as it should be const, and more importantly, it'd fail the build with
fmtlib v9, as its caller(s) is marked as `const`.

Signed-off-by: Kefu Chai <tchaikov@gmail.com>

diff --git a/src/osd/scrubber/scrub_backend.h b/src/osd/scrubber/scrub_backend.h
index d2ff62f96fd958d992a0780fc1489eeb3c71bf1a..3e644b241ff9f351a7268569b0dafbdc978cd8be 100644 (file)
--- a/src/osd/scrubber/scrub_backend.h
+++ b/src/osd/scrubber/scrub_backend.h
@@ -544,7 +544,7 @@ struct fmt::formatter<std::pair<hobject_t, data_omap_digests_t>> {
 
   template <typename FormatContext>
   auto format(const std::pair<hobject_t, data_omap_digests_t>& x,
-             FormatContext& ctx)
+             FormatContext& ctx) const
   {
     return fmt::format_to(ctx.out(),
                          "{{ {} - {} }}",