# Extra Clang Tools 21.1.8 documentation

## 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:

    // 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:

    // 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:

    // 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.