perf(encode): skip OmitEmpty slice allocation when no fields omitted#49
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perf(encode): skip OmitEmpty slice allocation when no fields omitted#49
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Two-pass approach: first counts surviving fields, returns fs.List directly if all survive (zero allocs). Only allocates the filtered slice when fields are actually omitted. Common case for time-series data where most fields have values.
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Summary
OmitEmpty: first counts surviving fields, returnsfs.Listdirectly if all survive (zero allocs)[]*fieldslice when fields are actually omittedDetails
Before this change, every struct encode with
omitemptytags (orSetOmitEmpty(true)) allocated a new[]*fieldslice even when no fields were empty. This is wasteful since the common case is all fields populated. The two-pass approach avoids this allocation entirely when no fields are omitted.Test plan