[CI] include-what-you-use

.github/workflows/iwyu.yml

@@ -0,0 +1,60 @@
+
+name: include-what-you-use
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  iwyu:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: 'recursive'
+
+      - name: setup dependencies
+        run: |
+          sudo apt update -y
+          sudo apt install -y --no-install-recommends --no-install-suggests \
+            build-essential \
+            iwyu \
+            cmake \
+            ninja-build \
+            libssl-dev \
+            libcurl4-openssl-dev \
+            libprotobuf-dev \
+            protobuf-compiler \
+            libgmock-dev \
+            libgtest-dev \
+            libbenchmark-dev
+
+      - name: Prepare CMake
+        run: |
+          TOPDIR=`pwd`
+          mkdir build && cd build
+          CC="clang" CXX="clang++" cmake \
+            -DCMAKE_CXX_INCLUDE_WHAT_YOU_USE="include-what-you-use;-w;-Xiwyu;--mapping_file=${TOPDIR}/.iwyu.imp;" \
+            -DBUILD_TESTING=OFF \
+            -DBUILD_W3CTRACECONTEXT_TEST=OFF \
+            ..
+
+      - name: iwyu_tool
+        run: |
+          cd build
+          make -k 2>&1 | tee -a iwyu.log
+
+      - uses: actions/upload-artifact@v4
+        if: success() || failure()
+        with:
+          name: Logs (include-what-you-use)
+          path: ./build/*.log
+
+      - name: count warnings
+        run: |
+          cd build
+          COUNT=`grep -c "Warning:" iwyu.log`
+          echo "include-what-you-use reported ${COUNT} warning(s)"
+

.iwyu.imp

@@ -0,0 +1,13 @@
+# Copyright The OpenTelemetry Authors
+# SPDX-License-Identifier: Apache-2.0
+
+# include-what-you-use mapping file
+
+[
+  # Work around for C++ STL
+  { "include": ["<bits/chrono.h>", "private", "<chrono>", "public"] },
+
+  # Local opentelemetry-cpp
+
+]
+

api/include/opentelemetry/version.h

@@ -3,7 +3,7 @@
 
 #pragma once
 
-#include "opentelemetry/common/macros.h"
+#include "opentelemetry/common/macros.h"  // IWYU pragma: export
 #include "opentelemetry/detail/preprocessor.h"
 
 #ifndef OPENTELEMETRY_ABI_VERSION_NO

sdk/include/opentelemetry/sdk/common/base64.h

@@ -5,7 +5,6 @@
 
 #include <string>
 
-#include "opentelemetry/common/macros.h"
 #include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/version.h"
 

sdk/include/opentelemetry/sdk/common/global_log_handler.h

@@ -3,7 +3,8 @@
 
 #pragma once
 
-#include <sstream>
+#include <sstream>  // IWYU pragma: keep
+#include <string>
 #include <utility>
 
 #include "opentelemetry/nostd/shared_ptr.h"

sdk/include/opentelemetry/sdk/metrics/async_instruments.h

@@ -6,8 +6,9 @@
 #include <memory>
 
 #include "opentelemetry/metrics/async_instruments.h"
-#include "opentelemetry/metrics/observer_result.h"
 #include "opentelemetry/sdk/metrics/instruments.h"
+#include "opentelemetry/sdk/metrics/state/metric_storage.h"
+#include "opentelemetry/sdk/metrics/state/observable_registry.h"
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
@@ -16,9 +17,6 @@ namespace sdk
 namespace metrics
 {
 
-class AsyncWritableMetricStorage;
-class ObservableRegistry;
-
 class ObservableInstrument : public opentelemetry::metrics::ObservableInstrument
 {
 public:

sdk/include/opentelemetry/sdk/metrics/meter_provider.h

@@ -7,34 +7,29 @@
 #include <memory>
 #include <mutex>
 
+#include "opentelemetry/metrics/meter.h"
 #include "opentelemetry/metrics/meter_provider.h"
 #include "opentelemetry/nostd/shared_ptr.h"
 #include "opentelemetry/nostd/string_view.h"
+#include "opentelemetry/sdk/metrics/meter_context.h"
+#include "opentelemetry/sdk/metrics/metric_reader.h"
+#include "opentelemetry/sdk/metrics/view/instrument_selector.h"
+#include "opentelemetry/sdk/metrics/view/meter_selector.h"
+#include "opentelemetry/sdk/metrics/view/view.h"
+#include "opentelemetry/sdk/metrics/view/view_registry.h"
+#include "opentelemetry/sdk/resource/resource.h"
+#include "opentelemetry/version.h"
 
 #ifdef ENABLE_METRICS_EXEMPLAR_PREVIEW
 #  include "opentelemetry/sdk/metrics/exemplar/filter_type.h"
 #endif
 
-#include "opentelemetry/sdk/metrics/view/view_registry.h"
-#include "opentelemetry/sdk/resource/resource.h"
-#include "opentelemetry/version.h"
-
 OPENTELEMETRY_BEGIN_NAMESPACE
-namespace metrics
-{
-class Meter;
-}  // namespace metrics
-
 namespace sdk
 {
 namespace metrics
 {
 
-// forward declaration
-class MeterContext;
-class MetricCollector;
-class MetricReader;
-
 class OPENTELEMETRY_EXPORT MeterProvider final : public opentelemetry::metrics::MeterProvider
 {
 public:

sdk/include/opentelemetry/sdk/metrics/meter_provider_factory.h

@@ -4,13 +4,10 @@
 #pragma once
 
 #include <memory>
-#include <mutex>
-#include <vector>
-#include "opentelemetry/metrics/meter.h"
+
 #include "opentelemetry/metrics/meter_provider.h"
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/sdk/metrics/meter.h"
 #include "opentelemetry/sdk/metrics/meter_context.h"
+#include "opentelemetry/sdk/metrics/view/view_registry.h"
 #include "opentelemetry/sdk/resource/resource.h"
 #include "opentelemetry/version.h"
 

sdk/include/opentelemetry/sdk/trace/batch_span_processor.h

@@ -3,24 +3,28 @@
 
 #pragma once
 
+#include <stddef.h>
 #include <atomic>
+#include <chrono>
 #include <condition_variable>
 #include <cstdint>
 #include <memory>
 #include <mutex>
 #include <thread>
 
 #include "opentelemetry/sdk/common/circular_buffer.h"
+#include "opentelemetry/sdk/trace/batch_span_processor_options.h"
+#include "opentelemetry/sdk/trace/exporter.h"
 #include "opentelemetry/sdk/trace/processor.h"
+#include "opentelemetry/sdk/trace/recordable.h"
+#include "opentelemetry/trace/span_context.h"
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
 {
-class SpanExporter;
-struct BatchSpanProcessorOptions;
 
 /**
  * This is an implementation of the SpanProcessor which creates batches of finished spans and passes

sdk/include/opentelemetry/sdk/trace/batch_span_processor_factory.h

@@ -5,16 +5,16 @@
 
 #include <memory>
 
+#include "opentelemetry/sdk/trace/batch_span_processor_options.h"
+#include "opentelemetry/sdk/trace/exporter.h"
+#include "opentelemetry/sdk/trace/processor.h"
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
 {
-class SpanExporter;
-class SpanProcessor;
-struct BatchSpanProcessorOptions;
 
 /**
  * Factory class for BatchSpanProcessor.

sdk/include/opentelemetry/sdk/trace/exporter.h

@@ -8,14 +8,14 @@
 
 #include "opentelemetry/nostd/span.h"
 #include "opentelemetry/sdk/common/exporter_utils.h"
+#include "opentelemetry/sdk/trace/recordable.h"
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
 {
-class Recordable;
 
 /**
  * SpanExporter defines the interface that protocol-specific span exporters must

sdk/include/opentelemetry/sdk/trace/random_id_generator.h

@@ -4,6 +4,8 @@
 #pragma once
 
 #include "opentelemetry/sdk/trace/id_generator.h"
+#include "opentelemetry/trace/span_id.h"
+#include "opentelemetry/trace/trace_id.h"
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE

sdk/include/opentelemetry/sdk/trace/random_id_generator_factory.h

@@ -5,14 +5,14 @@
 
 #include <memory>
 
+#include "opentelemetry/sdk/trace/id_generator.h"
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
 {
-class IdGenerator;
 
 /**
  * Factory class for RandomIdGenerator.

sdk/include/opentelemetry/sdk/trace/samplers/always_off_factory.h

@@ -5,14 +5,14 @@
 
 #include <memory>
 
+#include "opentelemetry/sdk/trace/sampler.h"
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
 {
-class Sampler;
 
 /**
  * Factory class for AlwaysOffSampler.

sdk/include/opentelemetry/sdk/trace/samplers/always_on_factory.h

@@ -5,14 +5,14 @@
 
 #include <memory>
 
+#include "opentelemetry/sdk/trace/sampler.h"
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
 {
-class Sampler;
 
 /**
  * Factory class for AlwaysOnSampler.

sdk/include/opentelemetry/sdk/trace/samplers/parent.h

@@ -4,28 +4,22 @@
 #pragma once
 
 #include <memory>
+#include <string>
 
+#include "opentelemetry/common/key_value_iterable.h"
 #include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/trace/sampler.h"
+#include "opentelemetry/trace/span_context.h"
+#include "opentelemetry/trace/span_metadata.h"
+#include "opentelemetry/trace/trace_id.h"
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
-namespace common
-{
-class KeyValueIterable;
-}  // namespace common
-
-namespace trace
-{
-class SpanContext;
-class SpanContextKeyValueIterable;
-class TraceState;
-}  // namespace trace
-
 namespace sdk
 {
 namespace trace
 {
+
 /**
  * The ParentBased sampler is a composite sampler. ParentBased(delegateSampler) either respects
  * the parent span's sampling decision or delegates to delegateSampler for root spans.

sdk/include/opentelemetry/sdk/trace/samplers/parent_factory.h

@@ -5,14 +5,14 @@
 
 #include <memory>
 
+#include "opentelemetry/sdk/trace/sampler.h"
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
 {
-class Sampler;
 
 /**
  * Factory class for ParentBasedSampler.

sdk/include/opentelemetry/sdk/trace/samplers/trace_id_ratio.h

@@ -3,6 +3,7 @@
 
 #pragma once
 
+#include <stdint.h>
 #include <string>
 
 #include "opentelemetry/nostd/string_view.h"
@@ -12,18 +13,6 @@
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
-namespace common
-{
-class KeyValueIterable;
-}  // namespace common
-
-namespace trace
-{
-class SpanContext;
-class SpanContextKeyValueIterable;
-class TraceState;
-}  // namespace trace
-
 namespace sdk
 {
 namespace trace