migrating-0.3-to-0.4.md

Migrating from 0.3 to 0.4

Version 0.4 removes global application configuration. Public function arities, return values, and default limits do not change.

Replace application configuration

EncodingRs no longer reads these settings:

config :encoding_rs,
  dirty_threshold: 128 * 1024,
  max_input_size: 10 * 1024 * 1024

Pass the settings to the operation that needs them:

EncodingRs.decode(data, "shift_jis",
  dirty_threshold: 128 * 1024,
  max_input_size: 10 * 1024 * 1024
)

For a manual chunk loop, set the options once when you create the decoder:

{:ok, decoder} =
  EncodingRs.Decoder.new("shift_jis",
    dirty_threshold: 128 * 1024,
    max_input_size: 256 * 1024
  )

EncodingRs.Decoder.decode_chunk(decoder, chunk, false)

Streams and batches accept the same options:

EncodingRs.Decoder.stream(chunks, "shift_jis", max_input_size: 256 * 1024)
EncodingRs.decode_batch(items, dirty_threshold: 128 * 1024)

Defaults

Calls without options still use a 64KB dirty scheduler threshold and a 100MB input limit. They do not read or traverse an option list.

Why this changed

Application configuration is global. A library may serve several consumers in one VM, and each consumer may need different limits. Explicit options keep that choice with the caller and avoid hidden runtime state.

Checklist

1. Change the dependency requirement to ~> 0.4.0.
2. Find each config :encoding_rs entry and move its values to the relevant call, stream, batch, or Decoder.new/2.
3. Remove the old application configuration.
4. Run the tests that cover large inputs and streaming boundaries.