Module materialize 

Materializing one trial’s RunConfig TOML from the base config.

The child receives the sampled values as rendered strings (ATUNE_PARAM_<key>) and the base config as text. materialize applies each value at its dotted key, sets the trial’s run.seed/run.root/ run.timestamp/run.slug, and re-serializes — the pure, unit-tested half of the objective (04-rl-and-oniro.md §B.1 seam #3: “decode assignment into section fields, or merge partial TOML”).

Typing the overlaid values

A rendered value is a string; the target config field wants a concrete TOML type. Rather than guessing from the string (which is lossy — a float value of exactly 1.0 renders as "1" and would be mistaken for an integer, and a choice(64, 128, 256) label is a string that must become an integer for an integer field), the value is coerced to the type the base config already has at that key. The base config is the source of truth for the field’s type, so train.hidden (an integer in the base) stays an integer and train.algo (a string) stays a string. A key absent from the base has no type to mirror and falls back to inferring int → float → bool → string.

The seed field

oniro’s run.seed is a u64, but a TOML integer is an i64, and the executor’s replicate seed spans the whole u64 range. The seed is therefore reduced to 63 bits with oniro_seed before it is written — a deterministic reduction, so a paired common-random-numbers seed is still common across trials (replicate j of trial i and trial i + 1 map to the same run.seed), which is the whole point of the pairing.

Constants

MAX_CONFIG_BYTES

The most bytes a RunConfig TOML may occupy, read or produced.

Functions

check_config_size

Refuses a config text that is over MAX_CONFIG_BYTES.

materialize

Builds one trial’s RunConfig TOML.

oniro_seed

Reduces a u64 replicate seed to a non-negative i64, so it fits oniro’s TOML integer run.seed field.