[CI] upgrade to clang-tidy 20

.clang-tidy

@@ -38,4 +38,4 @@ Checks: >
   -cppcoreguidelines-macro-usage,
   -cppcoreguidelines-non-private-member-variables-in-classes,
   -cppcoreguidelines-avoid-non-const-global-variables,
-  -cppcoreguidelines-pro-*
+  -cppcoreguidelines-pro-*

.devcontainer/Dockerfile.dev

@@ -15,13 +15,18 @@ COPY ci /opt/ci
 
 RUN apt update && apt install -y wget \
     ninja-build \
-    llvm-dev \
-    libclang-dev \
-    clang-tidy \
+    llvm-20-dev \
+    libclang-20-dev \
+    clang-tidy-20 \
     shellcheck \
     sudo \
     cmake
 
+RUN update-alternatives --install /usr/bin/clang-tidy clang-tidy /usr/bin/clang-tidy-20 200 && \
+    update-alternatives --install /usr/bin/llvm-config llvm-config /usr/bin/llvm-config-20 200 && \
+    update-alternatives --config clang-tidy && \
+    update-alternatives --config llvm-config
+
 RUN cd /opt/ci && bash setup_ci_environment.sh
 RUN cd /opt/ci && bash install_iwyu.sh
 

.github/workflows/clang-tidy.yaml

@@ -53,12 +53,11 @@ jobs:
         run: |
           sudo -E ./ci/install_thirdparty.sh --install-dir /usr/local --tags-file third_party_release --packages "ryml"
 
-      - name: Check clang-tidy
+      - name: Install clang-tidy-20
         run: |
-          if ! command -v clang-tidy &> /dev/null; then
-            echo "clang-tidy could not be found"
-            exit 1
-          fi
+          sudo apt install -y clang-tidy-20
+          sudo update-alternatives --install /usr/bin/clang-tidy clang-tidy /usr/bin/clang-tidy-20 200
+          sudo update-alternatives --config clang-tidy
           echo "Using clang-tidy version: $(clang-tidy --version)"
           echo "clang-tidy installed at: $(which clang-tidy)"
 
@@ -68,37 +67,63 @@ jobs:
           CXX: clang++
         run: |
           echo "Running cmake..."
-          cmake -B build-${{ matrix.cmake_options }} \
+          cmake \
+            -S . \
+            -B build-${{ matrix.cmake_options }} \
             -C ./test_common/cmake/${{ matrix.cmake_options }}.cmake \
             -DCMAKE_CXX_STANDARD=14 \
             -DWITH_STL=CXX14 \
             -DWITH_OPENTRACING=OFF \
             -DCMAKE_CXX_FLAGS="-Wno-deprecated-declarations" \
             -DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
-            -DCMAKE_CXX_CLANG_TIDY="clang-tidy;--quiet;-p;build-${{ matrix.cmake_options }}"
+            -DCMAKE_CXX_CLANG_TIDY="clang-tidy;--header-filter=.*/opentelemetry-cpp/.*;--exclude-header-filter=.*(internal/absl|third_party|third-party)/.*;--quiet"
 
-      - name: Run clang-tidy
+      - name: Run clang-tidy and Build
+        id: build
         run: |
-          cmake --build build-${{ matrix.cmake_options }} -- -j$(nproc) 2>&1 | tee clang-tidy-${{ matrix.cmake_options }}.log
+          BUILD_LOG=clang-tidy-${{ matrix.cmake_options }}.log
+          set -o pipefail
+          cmake --build build-${{ matrix.cmake_options }} -- -j$(nproc) 2>&1 | tee $BUILD_LOG
+          echo "build_log=$BUILD_LOG" >> "$GITHUB_OUTPUT"
 
-      - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+      - name: Analyze clang-tidy build log
+        id: analyze
+        run: |
+          SCRIPT_OUTPUT=$(python3 ./ci/create_clang_tidy_report.py \
+            --job_name ${{ matrix.cmake_options }} \
+            --build_log clang-tidy-${{ matrix.cmake_options }}.log \
+            --output ./clang_tidy_report-${{ matrix.cmake_options }}.md)
+          export $SCRIPT_OUTPUT
+          echo "Found $TOTAL_WARNINGS unique warnings"
+          echo "clang-tidy report generated at $REPORT_PATH"
+          echo "warning_count=$TOTAL_WARNINGS" >> "$GITHUB_OUTPUT"
+          echo "report_path=$REPORT_PATH" >> "$GITHUB_OUTPUT"
+          cat $REPORT_PATH >> $GITHUB_STEP_SUMMARY
+
+      - name: Upload build log
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
         with:
           name: Logs-clang-tidy-${{ matrix.cmake_options }}
-          path: ./clang-tidy-${{ matrix.cmake_options }}.log
+          path: ${{ steps.build.outputs.build_log }}
+
+      - name: Upload warning report
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        with:
+          name: Report-clang-tidy-${{ matrix.cmake_options }}
+          path: ${{ steps.analyze.outputs.report_path }}
 
-      - name: Count warnings
+      - name: Check Warning Limits
         run: |
-          COUNT=$(grep -c "warning:" clang-tidy-${{ matrix.cmake_options }}.log)
-          echo "clang-tidy reported ${COUNT} warning(s) with cmake options preset '${{ matrix.cmake_options }}'"
+          readonly COUNT="${{ steps.analyze.outputs.warning_count }}"
+          readonly LIMIT="${{ matrix.warning_limit }}"
 
-          readonly WARNING_LIMIT=${{ matrix.warning_limit }}
+          echo "clang-tidy reported ${COUNT} unique warning(s) with preset '${{ matrix.cmake_options }}'"
+          echo "Limit is ${LIMIT}"
 
-          # FAIL the build if COUNT > WARNING_LIMIT
-          if [ $COUNT -gt $WARNING_LIMIT ] ; then
-            echo "clang-tidy reported ${COUNT} warning(s) exceeding the existing warning limit of ${WARNING_LIMIT} with cmake options preset '${{ matrix.cmake_options }}'"
+          if [ "$COUNT" -gt "$LIMIT" ]; then
+            echo "::error::clang-tidy reported ${COUNT} warning(s) exceeding the limit of ${LIMIT}"
             exit 1
-          # WARN in annotations if COUNT > 0
-          elif [ $COUNT -gt 0 ] ; then
-            echo "::warning::clang-tidy reported ${COUNT} warning(s) with cmake options preset '${{ matrix.cmake_options }}'"
+          elif [ "$COUNT" -gt 0 ]; then
+            echo "::warning::clang-tidy reported ${COUNT} warning(s) within the limit of ${LIMIT}"
           fi
 

ci/create_clang_tidy_report.py

@@ -0,0 +1,172 @@
+# Copyright The OpenTelemetry Authors
+# SPDX-License-Identifier: Apache-2.0
+
+import argparse
+import re
+import sys
+from collections import defaultdict
+from enum import Enum
+from pathlib import Path
+from typing import Dict, List, NamedTuple, Optional, Set
+
+# --- Configuration ---
+REPO_NAME = "opentelemetry-cpp"
+MAX_ROWS = 1000
+WARNING_RE = re.compile(
+    r"^(?P<file>.+):(?P<line>\d+):(?P<col>\d+): warning: (?P<msg>.+) "
+    r"\[(?P<check>.+)\]$"
+)
+ANSI_RE = re.compile(r"\x1B(?:[@-Z\\-_]|\[[0-?]*[ -/]*[@-~])")
+
+
+class OutputKeys(str, Enum):
+    TOTAL_WARNINGS = "TOTAL_WARNINGS"
+    REPORT_PATH = "REPORT_PATH"
+
+
+class ClangTidyWarning(NamedTuple):
+    file: str
+    line: int
+    col: int
+    msg: str
+    check: str
+
+
+def clean_path(path: str) -> str:
+    """Strip path prefix to make it relative to the repo or CWD."""
+    if f"{REPO_NAME}/" in path:
+        return path.split(f"{REPO_NAME}/", 1)[1]
+    try:
+        return str(Path(path).relative_to(Path.cwd()))
+    except ValueError:
+        return path
+
+
+def parse_log(log_path: Path) -> Set[ClangTidyWarning]:
+    if not log_path.exists():
+        sys.exit(f"[ERROR] Log not found: {log_path}")
+    unique = set()
+    with log_path.open("r", encoding="utf-8", errors="replace") as f:
+        for line in f:
+            line = ANSI_RE.sub("", line.strip())
+            if "warning:" not in line:
+                continue
+            match = WARNING_RE.match(line)
+            if match:
+                unique.add(
+                    ClangTidyWarning(
+                        clean_path(match.group("file")),
+                        int(match.group("line")),
+                        int(match.group("col")),
+                        match.group("msg"),
+                        match.group("check"),
+                    )
+                )
+    return unique
+
+
+def generate_report(
+    warnings: Set[ClangTidyWarning],
+    output_path: Path,
+    job_name: Optional[str] = None,
+):
+    by_check: Dict[str, List[ClangTidyWarning]] = defaultdict(list)
+    by_file: Dict[str, List[ClangTidyWarning]] = defaultdict(list)
+
+    for w in warnings:
+        by_check[w.check].append(w)
+        by_file[w.file].append(w)
+
+    with output_path.open("w", encoding="utf-8") as md:
+        title = "# "
+        if job_name:
+            title += f"{job_name}"
+
+        md.write(
+            f"{title} `clang-tidy` job \t[**{len(warnings)} warnings**]\n\n"
+        )
+        md.write(f"<details><summary><b>{'Warnings breakdown'}</b><i>  - Click to expand</i></summary>\n\n")
+
+        def write_section(
+            title, data, item_sort_key, header, row_fmt, group_key, reverse
+        ):
+            md.write(f"## {title}\n")
+            sorted_groups = sorted(
+                data.items(), key=group_key, reverse=reverse
+            )
+            for key, items in sorted_groups:
+                md.write(
+                    f"<details><summary><b>{key} ({len(items)})</b></summary>"
+                    f"\n\n{header}\n"
+                )
+                for i, w in enumerate(sorted(items, key=item_sort_key)):
+                    if i >= MAX_ROWS:
+                        remaining = len(items) - i
+                        md.write(
+                            f"| ... | ... | *{remaining} more omitted...* |\n"
+                        )
+                        break
+                    md.write(row_fmt(w) + "\n")
+                md.write("\n</details>\n\n")
+
+        # Warnings by File: Sorted Alphabetically
+        write_section(
+            "Warnings by File",
+            by_file,
+            item_sort_key=lambda w: w.line,
+            header="| Line | Check | Message |\n|---|---|---|",
+            row_fmt=lambda w: f"| {w.line} | `{w.check}` | {w.msg} |",
+            group_key=lambda x: x[0],
+            reverse=False,
+        )
+
+        # Warnings by clang-tidy check: Sort by Warning count
+        write_section(
+            "Warnings by `clang-tidy` Check",
+            by_check,
+            item_sort_key=lambda w: (w.file, w.line),
+            header="| File | Line | Message |\n|---|---|---|",
+            row_fmt=lambda w: f"| `{w.file}` | {w.line} | {w.msg} |",
+            group_key=lambda x: len(x[1]),
+            reverse=True,
+        )
+
+        md.write(f"</details>\n")
+        md.write("\n----\n")
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "-l",
+        "--build_log",
+        type=Path,
+        required=True,
+        help="Clang-tidy log file",
+    )
+    parser.add_argument(
+        "-o",
+        "--output",
+        type=Path,
+        default="clang_tidy_report.md",
+        help="Output report path",
+    )
+    parser.add_argument(
+        "-j",
+        "--job_name",
+        type=str,
+        help="Job name to include in the report title",
+    )
+    args = parser.parse_args()
+
+    warnings = parse_log(args.build_log)
+    generate_report(warnings, args.output, args.job_name)
+
+    sys.stdout.write(f"{OutputKeys.TOTAL_WARNINGS.value}={len(warnings)}\n")
+    if args.output.exists():
+        sys.stdout.write(f"{OutputKeys.REPORT_PATH.value}={args.output.resolve()}\n")
+    else:
+        sys.exit(f"[ERROR] Failed to write report: {args.output.resolve()}")
+
+if __name__ == "__main__":
+    main()

ci/do_ci.sh

@@ -341,17 +341,24 @@ elif [[ "$1" == "cmake.legacy.test" ]]; then
 elif [[ "$1" == "cmake.clang_tidy.test" ]]; then
   cd "${BUILD_DIR}"
   rm -rf *
-  export BUILD_ROOT="${BUILD_DIR}"
+  clang-tidy --version
+  LOG_FILE="${BUILD_DIR}/opentelemetry-cpp-clang-tidy.log"
   cmake -S ${SRC_DIR} \
     -B ${BUILD_DIR} \
     -C ${SRC_DIR}/test_common/cmake/all-options-abiv2-preview.cmake  \
     "${CMAKE_OPTIONS[@]}" \
     -DWITH_OPENTRACING=OFF \
     -DCMAKE_CXX_FLAGS="-Wno-deprecated-declarations" \
     -DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
-    -DCMAKE_CXX_CLANG_TIDY="clang-tidy;--quiet;-p;${BUILD_DIR}"
-  make -j $(nproc)
+    -DCMAKE_CXX_CLANG_TIDY="clang-tidy;--header-filter=.*/opentelemetry-cpp/.*;--exclude-header-filter=.*(internal/absl|third_party|third-party)/.*;--quiet"
+  make -j $(nproc) 2>&1 | tee "$LOG_FILE"
   make test
+  SCRIPT_OUTPUT=$(python3 ${SRC_DIR}/ci/create_clang_tidy_report.py \
+            --build_log "$LOG_FILE" \
+            --output clang_tidy_report.md)
+  export $SCRIPT_OUTPUT
+  echo "total warnings = $TOTAL_WARNINGS"
+  echo "clang-tidy report generated at $REPORT_PATH"
   exit 0
 elif [[ "$1" == "cmake.legacy.exporter.otprotocol.test" ]]; then
   cd "${BUILD_DIR}"