Files
Niels LohmannandClaude Sonnet 5 ed513715a8 Document that a NUL byte in the input is treated as end of input (#5534)
* docs: document that a NUL byte in the input is treated as end of input

A NUL byte anywhere in the input - trailing, or embedded ahead of more
otherwise well-formed JSON - is currently treated the same as genuine
end of input, so parsing silently stops there instead of raising the
parse_error.101 any other unexpected byte triggers. This mirrors the
NUL-terminated-C-string convention already used when no explicit input
length is given (json::parse(const char*) already stops at strlen()),
just applied uniformly rather than only when a length is genuinely
unavailable.

This behavior predates this change and is not being altered here -
changing it would be an observable, backwards-incompatible behavior
change for any caller that (knowingly or not) depends on it, which is
not something to do silently in a patch. Documenting the current,
verified behavior as a new FAQ entry instead, so it's an intentional
and discoverable part of the contract rather than a surprise.

Fixes #5530.

Signed-off-by: Niels Lohmann <niels.lohmann@gmail.com>
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N4RQ1Ahan5YAGbnAQGjZTY

* Add JSON_STRICT_NUL_HANDLING opt-in macro for issue #5530

A NUL byte anywhere in the input is currently treated the same as real
end of input, rather than raising parse_error.101 like any other
unexpected byte (documented in the previous commit's FAQ entry). A full
unconditional fix was tried in PR #5532 but rejected as too risky to
ship by default: any caller could depend on the current behavior, even
unknowingly (e.g. a zero-padded buffer). On PR #5534, gregmarr proposed
a compile-time opt-in flag instead, and the maintainer agreed, wanting
it available now and defaulting to the corrected behavior in 4.0.0.

This mirrors the existing JSON_BRACE_INIT_COPY_SEMANTICS precedent as
closely as sensible:
- JSON_STRICT_NUL_HANDLING defaults to 0 (off); the three lexer sites
  that treat '\0' as EOF/comment-terminator are gated with
  `#if !JSON_STRICT_NUL_HANDLING` so the default-off behavior is
  byte-for-byte identical to today's.
- input_adapters.hpp's `T (&array)[N]` overload additionally trims a
  single trailing '\0' from a `char` array (e.g. a string literal like
  `json::parse("123")`) when the macro is on, so that case keeps
  working; every other element type (unsigned char, std::uint8_t, ...)
  always keeps its full extent. This intentionally does *not* reuse the
  existing strlen()-based pointer overload via SFINAE-excluding `char`
  from the array overload, as originally sketched for this change: that
  approach is ambiguous against the newer generic container overload
  added since PR #5532, and even where it compiles, strlen()-scanning a
  `char` array that is not NUL-terminated within its bounds reads past
  the end of the array (confirmed with AddressSanitizer). Trimming only
  a single trailing byte, without scanning, avoids both problems.
- Documented via docs/mkdocs/docs/api/macros/json_strict_nul_handling.md,
  linked from the macros index/nav/features page, the FAQ entry, and
  the parse/accept/operator>> reference pages.
- Tested in unit-class_parser.cpp and unit-deserialization.cpp, default
  state unguarded and opt-in state guarded. Since the library itself
  #undefs the macro at the end of json.hpp (as JSON_BRACE_INIT_COPY_SEMANTICS
  already does), a plain `#if defined(JSON_STRICT_NUL_HANDLING)` guard
  after the include never actually triggers; the tests instead capture
  the command-line value into a test-local macro before including the
  header. A few pre-existing fixtures elsewhere (std::array<uint8_t, N>
  sized one larger than their literal, relying on value-initialization
  to silently add a trailing zero byte) needed the same one-byte
  adjustment to keep passing under the opt-in behavior.

Unlike the precedent, this adds a proper `JSON_StrictNulHandling` CMake
option (rather than a raw -DCMAKE_CXX_FLAGS injection) and wires its
ci_test_strict_nul_handling target into the ci_cmake_options job matrix
in .github/workflows/ubuntu.yml, so the opt-in build is actually
exercised in CI -- closing the one gap in the precedent's own CI setup
(ci_test_brace_init_copy_semantics is defined but never referenced by
any workflow, so it has never actually run).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Clarify where JSON_STRICT_NUL_HANDLING does not reject NUL bytes

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <niels.lohmann@gmail.com>
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>
2026-09-24 06:55:21 +02:00

406 lines
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YAML

name: Ubuntu
on:
push:
branches:
- develop
- master
- release/*
pull_request:
workflow_dispatch:
permissions:
contents: read
concurrency:
group: ${{ github.workflow }}-${{ github.ref || github.run_id }}
cancel-in-progress: true
jobs:
ci_test_gcc:
runs-on: ubuntu-latest
container: gcc:latest
steps:
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ci_test_gcc
ci_infer:
runs-on: ubuntu-latest
steps:
- name: Harden Runner
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
- name: Install Infer
run: |
wget -q -O - "https://github.com/facebook/infer/releases/download/v1.3.0/infer-linux-x86_64-v1.3.0.tar.xz" | sudo tar -C /opt -xJ
sudo ln -s /opt/infer-linux-x86_64-v1.3.0/bin/infer /usr/local/bin/infer
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ci_infer
ci_static_analysis_ubuntu:
runs-on: ubuntu-latest
strategy:
matrix:
target: [ci_test_amalgamation, ci_test_single_header, ci_cppcheck, ci_cpplint, ci_reproducible_tests, ci_non_git_tests, ci_offline_testdata, ci_reuse_compliance, ci_test_valgrind]
steps:
- name: Harden Runner
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
- name: Install Valgrind
run: sudo apt-get update ; sudo apt-get install -y valgrind
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ${{ matrix.target }}
ci_static_analysis_clang:
runs-on: ubuntu-latest
container: silkeh/clang:dev
strategy:
matrix:
target: [ci_test_clang, ci_clang_tidy, ci_test_clang_sanitizer, ci_clang_analyze, ci_single_binaries]
steps:
- name: Install git, clang-tools, iwyu (ci_single_binaries), and unzip
run: apt-get update ; apt-get install -y git clang-tools iwyu unzip
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ${{ matrix.target }}
ci_cmake_options:
runs-on: ubuntu-latest
container: ubuntu:focal
strategy:
matrix:
target: [ci_cmake_flags, ci_test_diagnostics, ci_test_diagnostic_positions, ci_test_noexceptions, ci_test_noimplicitconversions, ci_test_legacycomparison, ci_test_noglobaludls, ci_test_disableenumserialization, ci_test_skiplibraryversioncheck, ci_test_simdutf, ci_test_strict_nul_handling]
steps:
- name: Install build-essential
run: apt-get update ; apt-get install -y build-essential unzip wget git libssl-dev
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ${{ matrix.target }}
ci_test_coverage:
runs-on: ubuntu-latest
steps:
- name: Harden Runner
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Install dependencies and de_DE locale
run: |
sudo apt-get clean
sudo apt-get update
sudo apt-get install -y build-essential cmake lcov ninja-build make locales gcc-multilib g++-multilib
sudo locale-gen de_DE
sudo update-locale
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ci_test_coverage
- name: Archive coverage report
uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
with:
name: code-coverage-report
path: ${{ github.workspace }}/build/html
- name: Publish report to Coveralls
uses: coverallsapp/github-action@8d6379e14d29928660c4ba802d8e85393440b329 # v2.3.8
with:
github-token: ${{ secrets.GITHUB_TOKEN }}
path-to-lcov: ${{ github.workspace }}/build/json.info.filtered.noexcept
fail-on-error: false
ci_test_compilers_gcc_old:
runs-on: ubuntu-latest
strategy:
matrix:
compiler: ['4.8', '4.9', '5', '6']
# official gcc:4.8/4.9/5/6 images fail to check out code (too old for
# actions/checkout); install the old compilers on top of official ubuntu:20.04
# instead, mirroring what the (now retired) custom json-ci image did.
container: ubuntu:20.04
steps:
- name: Install g++-${{ matrix.compiler }}
run: |
export DEBIAN_FRONTEND=noninteractive
apt-get update
apt-get install -y --no-install-recommends software-properties-common ca-certificates gnupg make git
# add-apt-repository resolves the PPA through the Launchpad API,
# which intermittently times out or fails the team lookup (the plain
# "deb ..." sources below never hit Launchpad and never flake).
# Retry with backoff so a transient Launchpad blip does not fail CI.
for attempt in 1 2 3 4 5; do
add-apt-repository -y ppa:ubuntu-toolchain-r/test && break
echo "::warning::add-apt-repository ppa:ubuntu-toolchain-r/test failed (attempt ${attempt}/5); retrying"
sleep $((attempt * 10))
done
apt-add-repository -y "deb http://archive.ubuntu.com/ubuntu/ bionic main"
apt-add-repository -y "deb http://archive.ubuntu.com/ubuntu/ bionic universe"
apt-add-repository -y "deb http://archive.ubuntu.com/ubuntu/ xenial main"
apt-add-repository -y "deb http://archive.ubuntu.com/ubuntu/ xenial universe"
apt-add-repository -y "deb http://archive.ubuntu.com/ubuntu/ xenial-updates main"
apt-add-repository -y "deb http://archive.ubuntu.com/ubuntu/ xenial-updates universe"
apt-get update
apt-get install -y --no-install-recommends g++-${{ matrix.compiler }}
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Run CMake
run: CXX=g++-${{ matrix.compiler }} cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ci_test_compiler_g++-${{ matrix.compiler }}
ci_test_compilers_gcc:
runs-on: ubuntu-latest
strategy:
matrix:
# older GCC docker images (4, 5, 6) fail to check out code
compiler: ['7', '8', '9', '10', '11', '12', '13', '14', '15', 'latest']
container: gcc:${{ matrix.compiler }}
steps:
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ci_test_compiler_default
ci_test_compilers_clang:
runs-on: ubuntu-latest
strategy:
matrix:
compiler: ['3.4', '3.5', '3.6', '3.7', '3.8', '3.9', '4', '5', '6', '7', '8', '9', '10', '11', '12', '13', '14', '15-bullseye', '16', '17', '18', '19', '20', '21', '22', 'latest']
container: silkeh/clang:${{ matrix.compiler }}
steps:
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Set env FORCE_STDCPPFS_FLAG for clang 7 / 8 / 9 / 10
run: echo "JSON_FORCED_GLOBAL_COMPILE_OPTIONS=-DJSON_HAS_FILESYSTEM=0;-DJSON_HAS_EXPERIMENTAL_FILESYSTEM=0" >> "$GITHUB_ENV"
if: ${{ matrix.compiler == '7' || matrix.compiler == '8' || matrix.compiler == '9' || matrix.compiler == '10' }}
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ci_test_compiler_default
ci_test_standards_gcc:
runs-on: ubuntu-latest
container: gcc:latest
strategy:
matrix:
standard: [11, 14, 17, 20, 23, 26]
steps:
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ci_test_gcc_cxx${{ matrix.standard }}
ci_test_standards_clang:
runs-on: ubuntu-latest
container: silkeh/clang:latest
strategy:
matrix:
standard: [11, 14, 17, 20, 23, 26]
stdlib: [libcxx, libstdcxx]
steps:
- name: Install git and unzip
run: apt-get update ; apt-get install -y git unzip
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build with libc++
run: cmake --build build --target ci_test_clang_libcxx_cxx${{ matrix.standard }}
if: ${{ matrix.stdlib == 'libcxx' }}
- name: Build with libstdc++
run: cmake --build build --target ci_test_clang_cxx${{ matrix.standard }}
if: ${{ matrix.stdlib == 'libstdcxx' }}
ci_cuda_example:
runs-on: ubuntu-latest
strategy:
fail-fast: false
matrix:
# 11.8.0: newest pre-C++20 CUDA release, exercises the C++17 fallback
# path (tests/cuda_example/CMakeLists.txt picks the standard per nvcc
# version); 12.1.1: permanent regression guard for #3907 (nvcc 12.0/12.1
# choke on enable_borrowed_range at C++20, fixed in 12.2); 12.6.3: recent
# CUDA/C++20 coverage.
cuda: ['11.8.0', '12.1.1', '12.6.3']
container: nvidia/cuda:${{ matrix.cuda }}-devel-ubuntu22.04
steps:
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ci_cuda_example
ci_module_cpp20:
strategy:
matrix:
container: ['gcc:latest', 'silkeh/clang:latest']
runs-on: ubuntu-latest
container: ${{ matrix.container }}
steps:
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
# The module test uses `import std;`, which needs CMake's experimental
# import-std support. Its opt-in token is CMake-version-specific, so pin
# CMake to the version whose token is set in tests/module_cpp20/CMakeLists.txt.
- name: Get pinned CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
with:
cmakeVersion: 4.3.4
# Clang: the std library module is provided by libc++ (the image's libstdc++
# ships none), and the image's libc++ module manifest has a broken relative
# path — repoint it at the real module sources.
- name: Use libc++ and fix its module manifest path (Clang)
if: matrix.container == 'silkeh/clang:latest'
run: |
echo "CXXFLAGS=-stdlib=libc++" >> "$GITHUB_ENV"
mkdir -p /usr/lib/share && ln -sf /usr/lib/llvm-*/share/libc++ /usr/lib/share/libc++
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ci_module_cpp20
ci_icpc:
runs-on: ubuntu-latest
# Intel discontinued the classic icc/icpc compiler in oneAPI 2024.0; this is
# Intel's own last officially published image that still includes it.
container: intel/oneapi-hpckit:2023.2.1-devel-ubuntu22.04
steps:
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
# No need to source setvars.sh here: unlike the old custom image, this
# official image already has the oneAPI environment (icc/icpc on PATH)
# baked in, and re-sourcing it fails with "already been run" (exit 3).
run: cmake --build build --target ci_icpc
ci_icpx:
runs-on: ubuntu-latest
container: intel/oneapi-hpckit:latest
steps:
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ci_icpx
ci_nvhpc:
runs-on: ubuntu-latest
container: nvcr.io/nvidia/nvhpc:25.5-devel-cuda12.9-ubuntu22.04
steps:
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ci_nvhpc
ci_emscripten:
runs-on: ubuntu-latest
steps:
- name: Harden Runner
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
- name: Install emscripten
uses: mymindstorm/setup-emsdk@4528d102f7230f0e7b276855c01ea1159be0e984 # v16
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Run CMake
run: cmake -S . -B build -DCMAKE_TOOLCHAIN_FILE=$EMSDK/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake -GNinja
- name: Build
run: cmake --build build
ci_test_documentation:
runs-on: ubuntu-latest
strategy:
matrix:
target: [ci_test_examples, ci_test_build_documentation]
steps:
- name: Harden Runner
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ${{ matrix.target }}