fix-tidy-errors

name	fix-tidy-errors
description	Fix clang-tidy errors that would fail the tidy-check CI stage
disable-model-invocation	true

Fix Tidy-Check CI Errors

Identify and fix all clang-tidy errors in the files changed on this branch that would fail the tidy-check CI stage.

Step 1: Locate clang-tidy

Check whether clang-tidy is available:

which clang-tidy || echo "not found"

• macOS: Homebrew LLVM is keg-only, so clang-tidy is not on PATH by default even after brew install llvm. Locate it with:

  find $(brew --prefix llvm)/bin -name 'clang-tidy' 2>/dev/null
  

  If not installed: brew install llvm. The binary will be at $(brew --prefix llvm)/bin/clang-tidy. Store this path — you'll need it as TIDY_BINARY in subsequent steps.

• Ubuntu/Debian: sudo apt-get install -y clang-tidy. It will be on PATH automatically.

Step 2: Verify branch

Confirm we are not on main:

git rev-parse --abbrev-ref HEAD

Stop if the result is main.

Step 3: Ensure the tidy build exists

The tidy build must be configured before running the diff check:

mkdir -p ./build/tidy && cd build/tidy && cmake -DCLANG_TIDY=1 -DDISABLE_UNITY=1 -DBUILD_EXTENSIONS=parquet -DBUILD_SHELL=0 ../..

This only runs cmake configuration (fast). Skip if build/tidy/compile_commands.json already exists.

Step 4: Run tidy-check-diff and capture errors

Run the diff-based tidy check against main. The make variable is GIT_BASE_BRANCH (not DUCKDB_GIT_BASE_BRANCH):

Linux (clang-tidy on PATH):

GIT_BASE_BRANCH=main make tidy-check-diff 2>&1

macOS (clang-tidy is keg-only; system headers require explicit sysroot):

make tidy-check-diff cannot pass the sysroot flag, so invoke the diff script directly:

TIDY_BINARY=$(find $(brew --prefix llvm)/bin -name 'clang-tidy') && \
SDK=$(xcrun --show-sdk-path) && \
git diff origin/main . ':(exclude)tools' ':(exclude)extension' ':(exclude)test' ':(exclude)benchmark' ':(exclude)third_party' ':(exclude)src/common/adbc' ':(exclude)src/main/capi' | \
python3 scripts/clang-tidy-diff.py \
  -path build/tidy \
  -quiet \
  -clang-tidy-binary "$TIDY_BINARY" \
  -extra-arg="-isysroot${SDK}" \
  -p1 2>&1

macOS note: Without -extra-arg="-isysroot...", Homebrew LLVM clang-tidy cannot find system headers (<memory>, <sstream>, etc.) and emits clang-diagnostic-error: file not found for every file. These are not real code errors — they are a local toolchain issue. Ignore them if the only errors are system header file not found diagnostics; they will not occur in Linux CI.

Capture the full output. If there are no errors (or only the macOS system-header false positives described above), report success and stop.

Step 5: Parse and group errors

From the tidy output, group errors by file and by check name. Each diagnostic line looks like:

src/some/file.cpp:42:10: error: [check-name] message

Common checks and how to fix them:

Check	Fix
modernize-use-nullptr	Replace NULL or 0 used as pointer with nullptr
modernize-use-override	Add override to virtual method overrides; remove redundant virtual keyword
google-explicit-constructor	Add explicit to single-argument constructors
google-build-using-namespace	Remove using namespace std; (or other namespaces); qualify names instead
google-runtime-int	Replace short/long/unsigned long etc. with sized types (int16_t, int64_t, uint64_t, etc.)
readability-braces-around-statements	Add braces {} around the body of if/else/for/while even for single-statement bodies
readability-container-size-empty	Replace .size() == 0 / .size() != 0 with .empty() / !.empty()
modernize-use-bool-literals	Replace integer literals 0/1 used as booleans with false/true
modernize-use-emplace	Replace .push_back(T(...)) with .emplace_back(...) for smart pointers listed in config
cppcoreguidelines-pro-type-cstyle-cast	Replace C-style casts (Type)x with static_cast<Type>(x), reinterpret_cast, or duckdb_py_cast as appropriate
cppcoreguidelines-pro-type-const-cast	Avoid ; redesign to remove the need

DuckDB-specific conventions (from CLAUDE.md):

• Use unique_ptr over shared_ptr; no raw new/delete
• Use idx_t for indices/counts, [u]int(8|16|32|64)_t for sized integers
• Use D_ASSERT for programmer-error assertions
• override or final on virtual overrides — never repeat virtual

Step 6: Fix errors file by file

For each file with errors:

1. Read the full file to understand context
2. Apply all fixes for that file in one edit
3. Do not reformat unrelated code — only change what tidy flagged

Step 7: Verify fixes

Re-run the same tidy command from Step 4 to confirm all errors are resolved. If new errors appear (e.g. from a fix that introduced another violation), fix those too and repeat until clean.

Step 8: Report

Summarize the fixes made: which files were changed and which checks were resolved.