[SDK] Handle instrumentation object construction failures safely by 22elix3r · Pull Request #4469 · open-telemetry/opentelemetry-cpp

22elix3r · 2026-08-21T17:35:04Z

Changes

Provider construction happens during SDK initialization. Runtime GetTracer / GetLogger / GetMeter calls must not throw. This change follows the post-SIG direction from @dbarker:

Remove noexcept from the SDK constructors for TracerProvider, LoggerProvider, MeterProvider, Tracer, Logger, and Meter. Allocation or initialization failures during provider construction can now propagate so the caller (often the configuration library) can handle them.
Keep GetTracer, GetLogger, and GetMeter noexcept. If constructing a previously unseen tracer/logger/meter fails, the provider catches the exception (when exceptions are enabled), logs via OTEL_INTERNAL_LOG_ERROR without letting logging escape, and returns a valid noop API object.
The noop fallback is allocated during provider construction (new NoopTracer / NoopLogger / NoopMeter stored as a nostd::shared_ptr). Runtime failure handling does not allocate a fresh noop object.
Failed construction is not inserted into the provider cache. A later Get* call can retry and return a normal SDK object once the failure is gone. Existing cached objects continue to be returned unchanged.
The complete fallible path is protected: instrumentation-scope construction, configurator evaluation, object allocation, shared_ptr control-block allocation, cache insertion, and metrics AddMeter.
Public API virtual method exception contracts are unchanged. ABI v1 and ABI v2 Get* signatures are unchanged. Try/catch is compiled only when OPENTELEMETRY_HAVE_EXCEPTIONS is set.

Tests added

Constructor noexcept static_asserts for each signal.
Deterministic fault injection through a ScopeConfigurator matcher that throws for a named scope.
After failure, Get* returns a valid noop-compatible object, using it produces no telemetry, the cache is not poisoned, cached objects are unchanged, and a later call recovers when the injected failure is removed.
Those tests are skipped when exceptions are disabled.

Validation

cmake -S . -B build -DCMAKE_BUILD_TYPE=Debug \
  -DOTELCPP_WITH_EXAMPLES=OFF -DOTELCPP_BUILD_TESTING=ON \
  -DOTELCPP_WITH_OTLP_GRPC=OFF -DOTELCPP_WITH_OTLP_HTTP=OFF \
  -DOTELCPP_WITH_OTLP_FILE=OFF -DCMAKE_CXX_STANDARD=17

cmake --build build --target tracer_provider_test logger_provider_sdk_test meter_provider_sdk_test
ctest --test-dir build --output-on-failure \
  -R 'trace.(TracerProvider|TracerConfig)|logs.(LoggerProviderSDK|LoggerConfig)|metrics.(MeterProvider|MeterConfig)'
# 63/63 passed, including Get*ReturnsNoopOnConstructionFailure

ctest --test-dir build --output-on-failure -R 'logs.LoggerSDK'
# 12/12 passed

./build/sdk/test/metrics/meter_test
# 20/20 passed

# Exception-disabled compile of changed SDK sources:
g++ -std=c++17 -fno-exceptions -c -DOPENTELEMETRY_HAVE_EXCEPTIONS=0 ...
# tracer_provider.cc, tracer.cc, logger_provider.cc, logger.cc,
# meter_provider.cc, meter.cc: success

# ABI v2 compile of the three provider .cc files:
g++ -std=c++17 -c -DOPENTELEMETRY_ABI_VERSION_NO=2 ...
# tracer_provider.cc, logger_provider.cc, meter_provider.cc: success

git diff --check
# clean

tools/format.sh was not run: clang-format is not installed in this environment.

CHANGELOG.md updated for non-trivial changes
Unit tests have been added
Changes in public API reviewed (SDK constructor exception specs only; API Get* contracts unchanged)

Remove noexcept from SDK TracerProvider, LoggerProvider, MeterProvider, Tracer, Logger, and Meter constructors so initialization-time allocation failures can propagate. Keep GetTracer/GetLogger/GetMeter noexcept and return a pre-allocated noop object if constructing a new instrumentation object fails, without caching the failed attempt. Fixes open-telemetry#4361 Signed-off-by: elix3r <157088510+22elix3r@users.noreply.github.com>

codecov · 2026-08-21T18:24:35Z

Codecov Report

❌ Patch coverage is 77.17391% with 21 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.59%. Comparing base (e30ef1d) to head (38e1c26).

Files with missing lines	Patch %	Lines
sdk/src/logs/logger_provider.cc	70.00%	9 Missing ⚠️
sdk/src/metrics/meter_provider.cc	78.58%	6 Missing ⚠️
sdk/src/trace/tracer_provider.cc	79.32%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4469      +/-   ##
==========================================
- Coverage   82.63%   82.59%   -0.04%     
==========================================
  Files         512      512              
  Lines       20139    20194      +55     
==========================================
+ Hits        16640    16677      +37     
- Misses       3499     3517      +18

Files with missing lines	Coverage Δ
sdk/include/opentelemetry/sdk/metrics/meter.h	`57.15% <ø> (ø)`
sdk/include/opentelemetry/sdk/trace/tracer.h	`100.00% <ø> (ø)`
sdk/src/logs/logger.cc	`94.12% <100.00%> (ø)`
sdk/src/metrics/meter.cc	`81.36% <100.00%> (ø)`
sdk/src/trace/tracer.cc	`80.22% <100.00%> (ø)`
sdk/src/metrics/meter_provider.cc	`85.51% <78.58%> (-6.80%)`	⬇️
sdk/src/trace/tracer_provider.cc	`83.96% <79.32%> (-4.75%)`	⬇️
sdk/src/logs/logger_provider.cc	`84.00% <70.00%> (-7.07%)`	⬇️

... and 1 file with indirect coverage changes

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Signed-off-by: elix3r <157088510+22elix3r@users.noreply.github.com>

22elix3r · 2026-08-22T15:22:38Z

@dbarker Latest commits are up (format/IWYU follow-up + merge from main). CI is waiting on workflow approval again.

Copilot

Pull request overview

This PR updates the OpenTelemetry C++ SDK to safely handle failures during instrumentation object construction while preserving noexcept guarantees for runtime GetTracer/GetLogger/GetMeter calls by returning a pre-allocated noop fallback when construction fails (with exception handling compiled in only when exceptions are enabled).

Changes:

Remove noexcept from SDK provider and instrumentation constructors so initialization failures can propagate to the caller.
Keep provider Get* methods noexcept, adding guarded try/catch to log construction failures and return a pre-allocated noop object without poisoning caches.
Add unit tests for constructor exception specs and deterministic fault injection/recovery behavior (skipped when exceptions are disabled).

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
sdk/test/trace/tracer_provider_test.cc	Adds static_asserts for constructor exception specs and tests noop fallback + recovery for `GetTracer`.
sdk/test/metrics/meter_provider_sdk_test.cc	Adds static_asserts and tests noop fallback + recovery for `GetMeter`.
sdk/test/logs/logger_provider_sdk_test.cc	Adds static_asserts and tests noop fallback + recovery for `GetLogger`; introduces a new test processor.
sdk/src/trace/tracer.cc	Removes `noexcept` from `Tracer` constructor implementation.
sdk/src/trace/tracer_provider.cc	Adds pre-allocated noop tracer fallback and exception-guarded construction in `GetTracer`.
sdk/src/metrics/meter.cc	Removes `noexcept` from `Meter` constructor implementation.
sdk/src/metrics/meter_provider.cc	Adds pre-allocated noop meter fallback and exception-guarded construction in `GetMeter`.
sdk/src/logs/logger.cc	Removes `noexcept` from `Logger` constructor implementation.
sdk/src/logs/logger_provider.cc	Adds pre-allocated noop logger fallback and exception-guarded construction in `GetLogger`.
sdk/include/opentelemetry/sdk/trace/tracer.h	Removes `noexcept` from `Tracer` constructor declaration.
sdk/include/opentelemetry/sdk/trace/tracer_provider.h	Removes `noexcept` from `TracerProvider` constructors; adds stored noop tracer member.
sdk/include/opentelemetry/sdk/metrics/meter.h	Removes `noexcept` from `Meter` constructor declaration.
sdk/include/opentelemetry/sdk/metrics/meter_provider.h	Removes `noexcept` from `MeterProvider` constructors; adds stored noop meter member.
sdk/include/opentelemetry/sdk/logs/logger.h	Removes `noexcept` from `Logger` constructor declaration.
sdk/include/opentelemetry/sdk/logs/logger_provider.h	Removes `noexcept` from `LoggerProvider` constructors; adds stored noop logger member.
CHANGELOG.md	Documents the SDK behavior change for constructor exception specs and noop fallback behavior.

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22elix3r · 2026-08-22T15:26:47Z

+  void OnEmit(std::unique_ptr<Recordable> &&record) noexcept override
+  {
+    ++emit_count_;
+    auto record_ptr = std::move(record);
+  }


Done — ignored the parameter instead of moving it into an unused local.

@22elix3r Thanks for the updates! Just sharing some context that Copilot is missing and why your original approach is preferred.

We've been using the pattern of moving args passed as rvalue references into temporary objects (sometimes named "unused") to ensure the method maintains ownership of the arg's lifetime. If we apply the (void)record approach then it is possible the record is not destroyed within the OnEmit method scope. This would be unexpected from the caller.

The auto record_ptr = std::move(record); approach is more explicit and matches the intended pattern of the production log record processors.

Restored auto record_ptr = std::move(record) so OnEmit still takes ownership of the record. Copilot's unused-variable note was a miss here. the unique_ptr destructor is the use.

Signed-off-by: elix3r <157088510+22elix3r@users.noreply.github.com>

Copilot

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

Restore CountingProcessor ownership of the OnEmit record via std::move. Add the includes IWYU asked for, and mark empty logging catches so clang-tidy does not count them against the unique-warning limit. Signed-off-by: elix3r <157088510+22elix3r@users.noreply.github.com>

…er-construction-4361 Signed-off-by: elix3r <157088510+22elix3r@users.noreply.github.com>

22elix3r · 2026-08-25T22:17:07Z

@dbarker IWYU and clang-tidy should be clean now. CountingProcessor uses std::move again, and the branch is merged onto latest main. Ready for another look when you have a minute.

22elix3r added 2 commits August 22, 2026 18:59

[SDK] Format provider construction changes and fix empty catch

a25cb86

Signed-off-by: elix3r <157088510+22elix3r@users.noreply.github.com>

Merge branch 'main' into fix/noexcept-provider-construction-4361

9209be9

22elix3r marked this pull request as ready for review August 22, 2026 15:18

22elix3r requested a review from a team as a code owner August 22, 2026 15:18

Copilot AI lite review requested due to automatic review settings August 22, 2026 15:18

Copilot started reviewing on behalf of 22elix3r August 22, 2026 15:18 View session

Copilot AI reviewed Aug 22, 2026

View reviewed changes

[SDK] Drop unused OnEmit local in CountingProcessor

38e1c26

Signed-off-by: elix3r <157088510+22elix3r@users.noreply.github.com>

22elix3r requested a lite review from Copilot August 22, 2026 15:27

Copilot AI reviewed Aug 22, 2026

22elix3r added 2 commits August 26, 2026 03:44

Merge remote-tracking branch 'upstream/main' into fix/noexcept-provid…

274e114

…er-construction-4361 Signed-off-by: elix3r <157088510+22elix3r@users.noreply.github.com>

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[SDK] Handle instrumentation object construction failures safely - #4469

[SDK] Handle instrumentation object construction failures safely#4469
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22elix3r commented Aug 21, 2026

Changes

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