Bring the Rust crate's idempotency, redirects, Retry-After and two form writes into line with the other SDKs

[robzolkos]

Four defects in the Rust crate, found while reviewing the Kotlin SDK on #198, which already behaves as described here. A Go PR is being opened in parallel for the two defects Go shares (idempotency and the reminders).

Idempotency ignored the behavior model

rust/generator decided whether a route may be resent from the spec's explicit x-hey-idempotent.natural alone, and short of one from the verb. behavior-model.json marks ten PATCH operations "idempotent": true — UpdateHabit, UpdateCalendarTodo, BulkUpdateClearances, UpdateClearance, UpdateCollection, UpdateContact, UpdateContactClearance, UpdateContactNote, UpdateMyClearance, UpdateSticky — so those went out once where their own policy (max: 2 on 429 and 503) says to resend. The generator now reads it as the Kotlin and TypeScript generators do: the explicit override first (UpdateMessage is a PUT with natural: false and stays non-idempotent), then the model's readonly || idempotent, and the verb only when the model says neither. Regenerating flips exactly those ten routes in routes.rs and nothing else. AGENTS.md now states the rule.

A 301 or 302 rewrote every non-GET to GET

redirected() turned anything but a GET or HEAD into a bodiless GET on a 301 or 302, so a PUT, PATCH or DELETE answered that way was followed as a read of the target and could report a mutation done that never reached it. RFC 9110 permits the rewrite on those statuses for a POST alone; a 303 applies retrieval to any method; a 307 or 308 keeps everything. The hop is now built by that rule.

Retry-After was honoured on a 429 alone

The retry loop read Retry-After on a 429 and a 503 but only waited as asked on the 429; a 503 saying how long the outage would last was resent after the backoff. RFC 9110 defines the header on a 503 for exactly that, and the TypeScript and Kotlin clients honour it on any status that earns a resend. The wait is now taken as asked on any retryable status; a header that asks for nothing or cannot be read still leaves the backoff to decide.

Reminders under the wrong list, and an emptied membership that sent nothing

update_event_fields filed reminders under all_day_reminder_durations[] only when the update itself said all_day: Some(true), else under timed_reminder_durations[]. HEY reads the list matching the event's all-day state after the write and unschedules the reminders when that list is absent, so an update leaving all_day as None on an all-day event cleared its reminders. When all_day is None the durations now go out under both keys, as Kotlin sends them; the one HEY does not read is ignored.

Extenzions::update looped over members, so Some(vec![]) sent nothing and could not be told from None. HEY replaces the membership whenever the field is present, and a form carries no empty array, so an explicitly empty list now goes out as one blank extenzion[members][], as an empty attendee list already does on a calendar event.

Tests

• Generator fixture: a PATCH the model calls idempotent, a PATCH it does not, and a PUT marked natural: false, checked on the emitted Route.
• Retry policy: UpdateSticky sent twice on a 503 then 200; UpdateMessage sent once on a 503; a 503 with Retry-After: 2 then 200 waits the two seconds and sends twice.
• Client unit tests: PUT + 302 stays a PUT with its body and content type; DELETE + 301 stays a DELETE; POST + 302 becomes a GET without body or content headers; DELETE + 303 becomes a GET; PATCH + 307 and POST + 308 keep method and body. The canned transport now records the body it was handed.
• Calendar events: all_day: None puts every duration under both keys; Some(true) under the all-day key only; Some(false) under the timed key only.
• Extenzions: Some(vec![]) sends one blank member; the existing None case still sends nothing.

GOWORK=off make rs-check rs-check-drift is green locally: fmt, clippy and tests with all features, clippy and tests with --no-default-features, the examples, cargo deny over both workspaces, the package dry-run and the generator drift check.

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Summary by cubic

Fixes four Rust SDK behaviors that diverge from the Kotlin and TypeScript SDKs: idempotency, redirects, Retry-After, and two form field writes.

Retry behavior

• The generator now reads idempotency from the behavior model before the verb, so the ten PATCH operations the model marks idempotent can be resent under their own policies; UpdateMessage keeps its explicit non-idempotent override.
• A 301 or 302 now rewrites only a POST into a bodiless GET, while PUT, PATCH, and DELETE keep method and body; 303 and 307/308 behave as before.
• Retry-After is now honored on any retryable status instead of only 429, so a 503 gets the wait it asks for; the README says so too.

Form writes

• Event updates that leave all_day unset now send reminders under both the all-day and timed keys, so editing an all-day event no longer clears its reminders.
• An explicitly empty extenzion membership now sends one blank member instead of nothing, so it clears the roster rather than leaving it unchanged.

^{Written for commit 4ca7b30. Summary will update on new commits.}

[Copilot]

🟡 Changes recommended

The public Rust README still documents Retry-After as applying only to 429 responses.

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Pull request overview

Aligns Rust SDK retries, redirects, idempotency, and form updates with other SDKs.

Changes:

• Corrects redirect and Retry-After behavior.
• Generates behavior-model-aware idempotency.
• Fixes calendar reminders and empty Extenzion memberships, with tests.

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File summaries

File	Description
AGENTS.md	Documents Rust idempotency generation.
rust/generator/src/model.rs	Incorporates behavior-model idempotency.
rust/generator/src/fixtures.rs	Tests idempotency precedence.
rust/hey-sdk/src/generated/routes.rs	Regenerates idempotent route metadata.
rust/hey-sdk/src/client.rs	Fixes redirects and retry waits.
rust/hey-sdk/src/services/calendar_events.rs	Sends reminders under appropriate keys.
rust/hey-sdk/src/services/extenzions.rs	Encodes empty memberships explicitly.
rust/hey-sdk/tests/retry_policy.rs	Covers retry behavior.
rust/hey-sdk/tests/services_calendar_events.rs	Covers reminder forms.
rust/hey-sdk/tests/services_extenzions.rs	Covers empty memberships.

Review details

• Files reviewed: 9/10 changed files
• Comments generated: 1
• Review effort level: Balanced

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[Copilot]

🟢 Approved

The behavior changes are consistent with their documented contracts and have focused regression coverage.

Review details

• Files reviewed: 10/11 changed files
• Comments generated: 0 new
• Review effort level: Balanced