.. title:: clang-tidy - abseil-duration-unnecessary-conversion
abseil-duration-unnecessary-conversion
======================================
Finds and fixes cases where ``absl::Duration`` values are being converted to
numeric types and back again.
Floating-point examples:
.. code-block:: c++
// Original - Conversion to double and back again
absl::Duration d1;
absl::Duration d2 = absl::Seconds(absl::ToDoubleSeconds(d1));
// Suggestion - Remove unnecessary conversions
absl::Duration d2 = d1;
// Original - Division to convert to double and back again
absl::Duration d2 = absl::Seconds(absl::FDivDuration(d1, absl::Seconds(1)));
// Suggestion - Remove division and conversion
absl::Duration d2 = d1;
Integer examples:
.. code-block:: c++
// Original - Conversion to integer and back again
absl::Duration d1;
absl::Duration d2 = absl::Hours(absl::ToInt64Hours(d1));
// Suggestion - Remove unnecessary conversions
absl::Duration d2 = d1;
// Original - Integer division followed by conversion
absl::Duration d2 = absl::Seconds(d1 / absl::Seconds(1));
// Suggestion - Remove division and conversion
absl::Duration d2 = d1;
Unwrapping scalar operations:
.. code-block:: c++
// Original - Multiplication by a scalar
absl::Duration d1;
absl::Duration d2 = absl::Seconds(absl::ToInt64Seconds(d1) * 2);
// Suggestion - Remove unnecessary conversion
absl::Duration d2 = d1 * 2;
Note: Converting to an integer and back to an ``absl::Duration`` might be a
truncating operation if the value is not aligned to the scale of conversion.
In the rare case where this is the intended result, callers should use
``absl::Trunc`` to truncate explicitly.