77 lines
2 KiB
ReStructuredText
77 lines
2 KiB
ReStructuredText
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.. title:: clang-tidy - bugprone-optional-value-conversion
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bugprone-optional-value-conversion
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==================================
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Detects potentially unintentional and redundant conversions where a value is
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extracted from an optional-like type and then used to create a new instance of
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the same optional-like type.
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These conversions might be the result of developer oversight, leftovers from
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code refactoring, or other situations that could lead to unintended exceptions
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or cases where the resulting optional is always initialized, which might be
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unexpected behavior.
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To illustrate, consider the following problematic code snippet:
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.. code-block:: c++
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#include <optional>
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void print(std::optional<int>);
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int main()
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{
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std::optional<int> opt;
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// ...
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// Unintentional conversion from std::optional<int> to int and back to
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// std::optional<int>:
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print(opt.value());
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// ...
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}
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A better approach would be to directly pass ``opt`` to the ``print`` function
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without extracting its value:
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.. code-block:: c++
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#include <optional>
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void print(std::optional<int>);
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int main()
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{
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std::optional<int> opt;
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// ...
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// Proposed code: Directly pass the std::optional<int> to the print
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// function.
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print(opt);
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// ...
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}
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By passing ``opt`` directly to the print function, unnecessary conversions are
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avoided, and potential unintended behavior or exceptions are minimized.
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Value extraction using ``operator *`` is matched by default.
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The support for non-standard optional types such as ``boost::optional`` or
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``absl::optional`` may be limited.
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Options:
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--------
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.. option:: OptionalTypes
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Semicolon-separated list of (fully qualified) optional type names or regular
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expressions that match the optional types.
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Default value is `::std::optional;::absl::optional;::boost::optional`.
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.. option:: ValueMethods
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Semicolon-separated list of (fully qualified) method names or regular
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expressions that match the methods.
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Default value is `::value$;::get$`.
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