The windows-11-arm runner image moved to windows-11-vs2026-arm64, which no
longer ships Visual Studio 2022, so the msvc-arm64 job failed at configure
time. Use the "Visual Studio 18 2026" generator like the msvc2026 job.
clang-tidy's modernize-raw-string-literal check flagged two string literals
in the nesting tests added by #5546 and #5547.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Bound the descent of the copy constructor
basic_json's copy constructor copied objects and arrays by handing the
container to its own copy constructor, which copy-constructs every element
and so reaches this constructor again, once per nesting level. A value
nested deeply enough exhausted the call stack and terminated the process
with a segmentation fault - no exception, nothing the caller could catch.
Parsing such a value works, as the parser is iterative, and so does
destroying one, as #1436 made destruction iterative.
Bound how far the copy descends rather than take the call stack away from
it. The first levels are copied exactly as they were - the containers copy
their own elements, which is by far the fastest way to fill them - and only
once the copy has descended 128 levels is the value below it finished
without the call stack, through an explicit worklist. Copying can therefore
no longer exhaust the stack, however deeply a value is nested, while a value
nested less deeply than the bound - all but a vanishing minority - is copied
by the very same code as before and pays only for one counter.
That counter lives in thread_local storage, as one shared between threads
would be raced. JSON_NO_THREAD_LOCAL switches it off for toolchains without
thread_local; copying then goes through the worklist right away, which
yields the same values but is measurably slower.
The deferred values are completed before the copy they belong to returns, so
a value copied while another copy is going on - by a custom base class, say -
is unaffected by the copy it is nested in.
operator= takes its argument by value, so copy assignment is fixed as well.
Copying is as fast as it was, within measurement noise (medians of 9
interleaved runs, clang -O3): -1.3% for an array of strings, +0.0% for a
flat object, +0.1% for a flat array of numbers, +0.3% for nested arrays,
+0.6% for nested objects and +1.2% for a twitter-like document. Copying a
three-key object costs about ten nanoseconds more, the counter. Deferring
every level instead, rather than only those below the bound, measured
between 3% and 9% slower depending on the shape of the value.
This fixes#5387 for the copy constructor. dump() is still recursive.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Test the copy constructor's iterative path in CI
The copy constructor descends into 128 levels before it finishes a value
without the call stack, so the iterative path is otherwise only reached
by the few tests that nest deeper than that.
JSON_NO_THREAD_LOCAL switches the descent off, which sends every value
down that path. Running the whole test suite that way covers it with
every object type, string type, allocator, and base class the suite
already exercises. The new ci_test_no_thread_local target does that; the
macro had no build coverage at all before.
Copying a nested value also has to carry over what the element-wise copy
constructor would have copied: the parents that JSON_DIAGNOSTICS relies
on, and the positions that JSON_DIAGNOSTIC_POSITIONS reports. Both are
now checked on either side of the descent bound, for objects and arrays.
Neither was tested before, and dropping either one makes the new tests
fail.
Also quantify what JSON_NO_THREAD_LOCAL costs a copy instead of calling
it "measurably slower".
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Split the regression tests so that they keep linking
Linking test-regression2 fails with "relocation truncated to fit:
IMAGE_REL_AMD64_REL32 against `.rdata'" once its object grows past what
the MinGW linker copes with, and the copy constructor's helpers push it
over: the object grows by 6.3%, from 4,654,128 to 4,944,920 bytes at -O0,
and develop links at the smaller of the two.
Building the tests optimized shrinks the object enough to link, but the
binaries clang 11.0.1 and clang 18.1.8 then produce crash before doctest
prints its first line - 39 of 102 tests on clang 18 - so the objects have
to become smaller rather than denser.
Moving the test cases that follow "regression tests 2" into a file of
their own brings that object to 4,687,888 bytes, which is 0.7% above the
size that links today rather than 6.3%. Both files still build for C++11,
C++17 and C++20, and run the same 9 test cases and 135 assertions as
before, now spread over two binaries.
New regression tests belong in unit-regression3.cpp from here on, which
is what CONTRIBUTING.md now says.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Do not use thread_local storage with Clang targeting MinGW
Every test that copies a value segfaults there - 42 of 105 on clang
11.0.1, 39 of 102 on clang 18.1.8 - while the same tests pass with GCC
targeting MinGW, with Clang targeting MSVC, and with every other
toolchain the library is tested on. The counter that bounds the copy
constructor's descent is the library's first use of thread_local, so
that job had never exercised it before.
JSON_NO_THREAD_LOCAL already covers toolchains without thread_local
storage, and copying yields the same values with it, only more slowly.
Define it for this one automatically.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Balance the warning suppression the split separated
unit-regression2.cpp opens a DOCTEST_CLANG_SUPPRESS_WARNING_PUSH block at
the top and closed it at the very bottom, which the split moved into
unit-regression3.cpp: one file was left with a push and no pop, the other
with a pop and no push, which clang reports as an error.
Give each file the pair it needs.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Check both shapes without a C-style array
clang-tidy rejects the array the two shapes were iterated over
(cppcoreguidelines-avoid-c-arrays). The array only existed because astyle
reformats a range-for over a braced initializer list into something
unreadable; naming the two cases avoids both.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Split the regression tests far enough to leave room
The first split left unit-regression2.cpp 0.7% below the size develop
links at, which the comparison change in the follow-up immediately used
up: the MinGW linker fails on test-regression2_cpp20 again, naming
copy_shallow and to_partial_ordering among the relocations it cannot fit.
Move the sections from "issue #2067" on, and the helper types they use,
so that the file stops being the one that decides whether the tests can
be linked at all. At -O0 and C++20, unit-regression2.cpp is now 2,964,944
bytes against develop's 4,708,248, and 3,070,568 bytes with the follow-up
applied - roughly a third smaller either way, rather than a fraction of a
percent larger.
The 135 assertions are the same ones as before, now spread over three
test cases in two files.
Also silence the clang-tidy findings the deep-nesting tests draw: the
copies they make are what is being tested, and the reserve() computation
gets its parentheses.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Move the #4804 alias to the file that uses it
The split left the json_4804 alias behind in unit-regression2.cpp while
the test case that uses it went to unit-regression3.cpp, which does not
build for C++17 and C++20 as a result.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Include <span> where the split moved its only use
The #2546 test case guards itself with __has_include(<span>), but the
include itself sat in unit-regression2.cpp's preamble and stayed behind,
so the section compiled without a declaration wherever the guard passed -
which nvhpc reported and libc++ builds do not, as they skip the section
altogether.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Keep the descent bookkeeping in one place
Copying carried a depth count, a depth limit and a guard of its own, and
the comparison in the follow-up added a second set beside them. Neither
operation needs its own: they are never nested inside one another by the
library - copying a value does not compare one, and comparing two values
does not copy them - and where user code nests them anyway, sharing the
count only ends a descent sooner than it had to.
So there is now one nesting_depth(), one nesting_depth_limit() and one
nesting_depth_guard, which the follow-up uses instead of adding its own.
Inverting the test in copy_structured leaves the too-deep case and the
no-thread-local case as the same code.
The guard takes the count rather than looking it up, because the caller
has looked it up already to test it against the limit, and reaching
thread-local storage twice on the path that is taken almost every time is
worth avoiding.
The switch that copies the value of anything that is not an object or an
array was written twice - once in the copy constructor, once in
copy_shallow - so that adding a value_t meant editing both, and missing
one would have been silent. It is copy_leaf_value now, and inlined: both
callers have already sorted the containers out, and folding that test into
the switch is what keeps a value made mostly of numbers copying as fast as
it did.
Copying canada.json, citm_catalog.json and twitter.json is within 0.6% of
what it was before, measured as a paired ratio over 18 interleaved rounds
against a run-to-run spread of 0.3%.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Check that an abandoned copy can still be destroyed
Copying a value without the call stack builds the copy from the top down,
and every value whose own copy has not been made yet stays a null value
until it is. That is what lets a copy be abandoned half-built: the
destructor finds nothing but complete values and null ones.
Nothing tested it. Failing an allocation part-way through a copy of a
deeply nested value does, with the allocator the file already has for
exactly this kind of test.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Name the test's locals so Flawfinder stops matching them
The code scanning job reports CWE-362 - "check when opening files" - for
a test that opens no files: Flawfinder matched a local variable called
open. Rename it and its partner.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Keep the descent guard's bookkeeping self-contained
nesting_depth_limit() and nesting_depth_guard were only used inside
the JSON_NO_THREAD_LOCAL-guarded branch of copy_structured(), but were
defined unconditionally. Move them inside the #ifndef, and have the
guard look up the depth and test it against the limit itself (via
okay()) instead of making the caller do it - the caller no longer
needs to touch nesting_depth() at all. Also shrink the thread-local
counter to std::uint8_t, matching what its own doc comment already
argued.
Addresses gregmarr's review comments on #5389.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Make nesting_depth_guard usable regardless of JSON_NO_THREAD_LOCAL
nesting_depth_limit() and nesting_depth() stay behind #ifndef
JSON_NO_THREAD_LOCAL, since a descent cannot be bounded without a
per-thread count. But the guard itself now always exists, becoming a
no-op that is never okay() under that macro - the same way the bound
is already reached on every call without one. copy_structured() no
longer needs to know which case it is in.
This is what lets #5390 reuse the guard for comparison, which cannot
test JSON_NO_THREAD_LOCAL where the macro-based operators use it: the
guard now carries that distinction itself instead of requiring every
caller to.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Silence VS2015's C4503 for the custom-base-class test
The deep-copy support added for #5387 lengthened the mangled name of
std::allocator_traits<...>::construct for the test's map type past
VS2015's limit, which /WX turns into a build failure even though the
name is only used for (now-truncated) debug info.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Remove dead unused-parameter casts from copy_metadata()
@gregmarr asked whether the static_cast<void> pair in the
JSON_DIAGNOSTIC_POSITIONS-off branch was needed for an empty
json_base_class_t. It isn't: src and dst are already referenced
unconditionally by the base-class copy above, so no -Wunused-parameter
warning fires either way (checked with -Wall -Wextra
-Wunused-parameter, JSON_DIAGNOSTIC_POSITIONS 0 and 1).
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Fix CI: build custom array types without a fill constructor, re-amalgamate
copy_array_level() built the destination array with the fill
constructor array_t(count, value), which is not part of the array
container interface the library otherwise assumes (e.g. custom
ArrayTypes that only provide a default and an iterator-pair
constructor, as covered by unit-custom-array-type.cpp). Default-
construct the array and resize() it instead, matching how the rest
of the codebase already grows array_t.
Also re-run the amalgamation, which had fallen out of sync with
include/nlohmann/json.hpp.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>
Linking test-regression2_cpp20 intermittently fails with
unit-regression2.cpp.obj:(.debug_info+0x16): relocation truncated to
fit: IMAGE_REL_AMD64_SECREL against `.debug_line'
The failure moves between matrix entries from run to run, and the same
commit can pass and fail on consecutive runs, so it is the size of the
debug sections rather than any one Clang version.
The jobs only build and run the tests, so override CMAKE_CXX_FLAGS_DEBUG
to drop the default -g. Everything else about the Debug build is
unchanged: no optimization flag is added and NDEBUG stays undefined, so
JSON_ASSERT remains active.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Improve MSVC C++ modules compatibility for nlohmann_json
- Keep complete module interface with all exports
- Export all standard types: json, basic_json, adl_serializer, json_pointer, ordered_json, ordered_map
- Export detail namespace symbols for advanced usage
- Ensure compatibility with MSVC C++20/23 modules
- Maintain full functionality without breaking changes
Signed-off-by: yudaichen <250074249@qq.com>
* Add C++20 module Windows CI test and fix file ending
- Add ci_module_cpp20 job to Windows workflow to verify module support with MSVC
- Add missing newline at end of json.cppm file
Signed-off-by: yudaichen <250074249@qq.com>
---------
Signed-off-by: yudaichen <250074249@qq.com>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* ⬆️ use new CI image
* ⬆️ use new CI image
* 🚨 suppress Clang-Tidy warnings
* 💚 use proper scan-build version
* 🚨 suppress Clang-Tidy warnings
* ⬆️ use more recent GitHub actions
* 💚 add missing compiler
* 📝 update used compilers
* 🚨 fix duplicate inclusion
* CI: add workflow_dispatch trigger
* CI: change msvc2019*/clang* runners to windows-2019
GitHub updated their runners. windows-latest is now based on Windows
Server 2022 and comes with different tool versions.
MSVC 2019 is still available via the windows-2019 runner.
Niels Lohmann
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