Struct RetentionConfig 

pub struct RetentionConfig { /* private fields */ }

Retention policy for the run store (R6). Defaults are the restrictive 50-per-agent / 30-day caps; ~/.car/config.toml [runs] overrides.

A non-positive cap is DISABLED, not zero-tolerance (car#1338). This used to be read literally, and the literal reading is destructive in the one direction nobody intends: max_per_agent = 0 made completed_rank >= 0 always true and max_age_days = 0 put the cutoff at now, so either value deleted every collectable run trace on the next boot, unrecoverably.

An operator writing 0 means “no cap” — that is what it means for max_session_wall_secs, and for the coder’s own max_sessions / max_session_age_days in the neighbouring ~/.car/coder.toml. Two similarly-named retention knobs in one daemon whose zero values inverted was a hazard whose failure mode was silent data loss, so the two now agree.

This is a choice, not an unqualified convention: CoderConfig’s max_check_timeout_secs and approval_patch_bytes read 0 as UNSET and fall back to their defaults, because zero would floor a check at one second or blind the approval surface. That treatment is the other candidate fix for this bug and it was rejected on the merits — “unset” restores 50/30, which still deletes, so it does not close the data loss. 0 is a legal value with an ambiguous meaning and this defines it; a value that could not have been intended (a negative or unrepresentable age) is a different case and is warned about at load. The fields are PRIVATE and the caps are read as Options, so “disabled” is a state this type carries rather than a sentinel every call site has to remember. That is not decoration: the bug was a bare rank >= cap comparison, and leaving the raw values public would let the next one be written with no compiler complaint.

Implementations

impl RetentionConfig

pub fn new(max_per_agent: usize, max_age_days: i64) -> Self

Build a policy. 0 (or a negative age) disables that cap — see the type’s note.

pub fn count_cap(&self) -> Option<usize>

The count cap, or None when disabled.

pub fn age_cap_days(&self) -> Option<i64>

The age cap in days, or None when disabled — including when the configured value cannot be turned into a cutoff at all.

impl RetentionConfig

pub fn from_car_dir(car_dir: &Path) -> Self

Load the retention policy from <car_dir>/config.toml’s [runs] section, falling back to the restrictive default for any missing key or an unreadable/malformed file (config errors must never make the daemon refuse to start — same posture as the rest of .car).

A present key is taken as written, 0 included — see the type’s note on what 0 means. Filtering it here would silently restore the default instead of honoring “keep everything”.

Trait Implementations

impl Clone for RetentionConfig

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for RetentionConfig

impl Debug for RetentionConfig

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for RetentionConfig

fn default() -> Self

Returns the “default value” for a type.