mirror of
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Niels Lohmann
63c10a51fc
* Review and extend the documentation, and check it in CI A review of all documentation pages found factual errors, dead links, missing cross-references, and gaps in examples. This fixes them and adds checks so the same problems are caught automatically. Fixes: - wrong signatures and version histories (operator!= C++20 member, binary() subtype type, get<PointerType>(), JSON_NO_THREAD_LOCAL, ...) - stale descriptions (number parsing since #5283, UBJSON table, SAX example that no longer compiled, tsl::ordered_map advice) - dead internal and external links; repology.org badges (the domain is suspended) replaced by badges that query the registries directly - deprecation notes link the migration guide; the guide itself fixed Additions: - "See also" sections, cross-references, 25 runnable examples, 12 Mermaid diagrams, new API pages for json_pointer::operator<=> and byte_container_with_subtype::operator==/!= - landing page, guides for untrusted input and performance - "unreleased" badge after versions newer than the latest release Checks: - strict documentation build (broken links/anchors fail it); CI and the publish workflow fetch the full history the build needs - weekly external link check, Mermaid syntax check in CI - check_structure.py: example titles, heading levels, alt texts, header links, docset index coverage; its unused-example check works again - all examples produce the same output on every platform Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Keep the customer links that could not be fixed A dead link on the customers page is still the evidence of where the use of the library was documented. Keep the original URLs of the entries without a working replacement (Marne, Cisco Webex Desk Camera, Philips Hue, CyberArk) and exclude exactly these URLs from the link check. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Correct the duplicate-key recipe's claim about SAX positions The SAX interface's key() receives no position either; only parse_error() does. Also note that the recipe does not report the path to the repeated key (see discussion #5085). Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Say the library is available as a single header and mention json_fwd.hpp Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Correct documentation errors found while hunting for bugs - patch/patch_inplace: list the JSON pointer errors parse_error.106-109 and out_of_range.402/404, and quote the actual parse_error.105 message. - unflatten: list parse_error.106/107/108 and out_of_range.404. - to_bson: list out_of_range.415 (binary subtype above 255) and note that 412 and 415 are new in 3.13.0. - to_string: state that string_t must be convertible to std::string, also in the StringType requirements table. - JSON Lines: a `while (input >> j)` loop also throws after the last value for concatenated JSON values; show a loop that works for both. - BON8: a string gets 0xFF only if nothing follows it in the message; a string at the end of an array or object is ended by 0xFE. - custom_string_type.hpp: add operator+=(char), which the "Always required" list asks for (json_pointer::to_string, flatten, unflatten, and diff did not compile), and an ADL int_to_string for diff and items. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Cache the release headers with functools.lru_cache Codacy (Pylint) flagged the mutable default argument that header() used as its cache. functools.lru_cache keeps the same memoization without it. The script's output is unchanged. Signed-off-by: Niels Lohmann <mail@nlohmann.me> --------- Signed-off-by: Niels Lohmann <mail@nlohmann.me>
89 lines
2.0 KiB
Markdown
89 lines
2.0 KiB
Markdown
# JSON_ASSERT
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```cpp
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#define JSON_ASSERT(x) /* value */
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```
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This macro controls which code is executed for [runtime assertions](../../features/assertions.md) of the library.
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## Parameters
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`x` (in)
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: expression of a scalar type
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## Default definition
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The default value is [`#!cpp assert(x)`](https://en.cppreference.com/w/cpp/error/assert).
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```cpp
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#define JSON_ASSERT(x) assert(x)
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```
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Therefore, assertions can be switched off by defining `NDEBUG`.
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## Notes
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- The library uses numerous assertions to guarantee invariants and to abort in case of otherwise undefined behavior
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(e.g., when calling [operator[]](../basic_json/operator%5B%5D.md) with a missing object key on a `const` object). See
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page [runtime assertions](../../features/assertions.md) for more information.
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- Defining the macro to code that does not call `std::abort` may leave the library in an undefined state.
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- The macro is undefined outside the library.
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## Examples
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??? example "Example: default behavior"
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The following code will trigger an assertion at runtime:
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```cpp
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#include <nlohmann/json.hpp>
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using json = nlohmann::json;
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int main()
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{
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const json j = {{"key", "value"}};
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auto v = j["missing"];
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}
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```
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Output:
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```
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Assertion failed: (m_value.object->find(key) != m_value.object->end()), function operator[], file json.hpp, line 2144.
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```
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??? example "Example: user-defined behavior"
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The assertion reporting can be changed by defining `JSON_ASSERT(x)` differently.
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```cpp
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#include <cstdio>
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#include <cstdlib>
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#define JSON_ASSERT(x) if(!(x)){fprintf(stderr, "assertion error in %s\n", __FUNCTION__); std::abort();}
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#include <nlohmann/json.hpp>
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using json = nlohmann::json;
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int main()
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{
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const json j = {{"key", "value"}};
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auto v = j["missing"];
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}
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```
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Output:
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```
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assertion error in operator[]
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```
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## See also
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- [Runtime Assertions](../../features/assertions.md) - overview documentation
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## Version history
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- Added in version 3.9.0.
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