[telemetry] endpoint carried one OTLP signal while its name implied it
covered every signal. That asymmetry is what let the metrics URL be
guessed later by rewriting this one's path suffix, so anything not
ending /v1/traces silently posted metrics to the traces path.
Renames the key to traces_endpoint and Setup::exporterEndpoint to
tracesEndpoint. The default value is unchanged and the URL is still used
verbatim, with no path derived from it. The startup log line and the
compose-file example name the new key, the latter being where an
operator copies it from.
No metrics_endpoint is added here: this branch has no metrics pipeline,
so the key would parse into a member nothing reads.
The trace-context checks validate bytes received from a peer, so a
discarded result means untrusted input was accepted unchecked. hashSpan(),
txReceiveSpan() and txProcessSpan() return an RAII guard; discarding one ends
the span on the same line it began.
The telemetry-disabled twins of both hashSpan overloads already carried the
attribute, so the two #ifdef arms now agree. Both hashSpan overloads also
gain the @return line their siblings already had, now that the result cannot
be dropped.
No caller in the chain discards any of these results.
getInstance(), getTracer(), both startSpan() overloads and networkTypeFromId()
return values that a caller must use. A discarded startSpan() result destroys
the returned span immediately, so the span opens and closes with no content.
Six methods in Telemetry.h already carried the attribute, on the base and on
every override. The new attributes follow that: the overrides in Telemetry.cpp
and NullTelemetry.cpp get it too, because [[nodiscard]] is not inherited and a
call bound to the derived type would otherwise be unchecked.
No caller anywhere in the chain discards any of these results.
The default setServiceInstanceId() body ignores its argument. Use the
attribute rather than a (void) cast: the codebase already uses it 104 times
and the build is C++23.
With telemetry compiled out, <string_view> in Telemetry.h and <memory> in
SpanGuard.h are named only by declarations that are themselves guarded, so
clang-tidy's include-cleaner reports them unused and warnings-as-errors fails
the build. NullTelemetry.cpp has the mirror problem: it names beast::Journal
only in the compiled-out makeTelemetry(), reaching the type transitively.
Guard each include to match the configuration that uses it, and correct three
comments that overstated what the empty destructors cost.
The compiled-out ScopedActivation, SpanGuard and ScopedSpanGuard each used a
defaulted destructor. A defaulted destructor on an empty class is trivial, so
compilers report any guard held only for its scope as an unused variable. With
telemetry compiled out that produced seven -Wunused-variable errors under
-Werror, across the ledger acquire, consensus, ledger master and overlay paths.
Write the three destructors by hand so destruction is not trivial, matching the
telemetry-enabled types, and assert that property so it cannot quietly regress
to `= default`. The bodies are empty, so no code is generated either way.
Also move <memory> inside the telemetry guard: only the telemetry-enabled types
hold a unique_ptr, so the include is unused when telemetry is compiled out.
The trace_state comment pointed at a planning document that is not part
of the shipped tree, so the reference would dangle for any reader of the
repository. State the reserved-and-inert fact on its own.
