Design model

Platform spec article

Design model

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Spec standingStandard

Owner

Piotr Mikstacki pmikstacki@cybernomad.it

Submitter

Piotr Mikstacki pmikstacki@cybernomad.it

Current document

ADRs (3)

1. 0050-channel-vs-onresize-delivery Channel vs OnResize delivery Accepted

   Cross-fiber resize uses Channel; same-fiber uses OnResize hub.

   Context

   Resize notifications must integrate with fiber concurrency without OS-thread callbacks.

   Decision

   Rule	Detail
   Cross-fiber	PollResize → Channel<ConsoleMessage>
   Same-fiber	OnResize event hub

   Consequences

   No separate OS-thread callback API in v1.

   Verification anchors

   ConsoleMessageChannelTests.bd.

   Open full ADR page

2. 0051-columns-lines-env-fallback COLUMNS/LINES env fallback Accepted

   Env size parsing is best-effort discrete table in v1.

   Context

   Not all hosts expose Winsize ioctl; env vars are a portable fallback.

   Decision

   Rule	Detail
   Order	Winsize ioctl then COLUMNS/LINES
   Parse	Discrete table, not full integer grammar in v1

   Consequences

   Odd env values may clamp or ignore per contracts article.

   Verification anchors

   Platform/Terminal.bd tests.

   Open full ADR page

3. 0052-silent-resize-send-failure Silent resize Send failure Accepted

   Failed resize Channel Send is silent in v1 poll loops.

   Context

   UI loops should not crash when consumers drop resize messages.

   Decision

   Rule	Detail
   EVT-002	Failed Send on resize is silent in v1
   Future	May gain diagnostics in a later ADR

   Consequences

   Poll loops continue after dropped resize notifications.

   Verification anchors

   ConsoleMessageChannelTests.bd; EVT-002 traceability.

   Open full ADR page

Articles

• Contracts and edge cases Resize polling and delivery requirements. article Standard Reviewed Thu May 21
• Design model ConsoleMessage variants and resize notification surfaces. article Standard Reviewed Thu May 21
• Examples Subscribing to resize via channel or event hub. article Standard Reviewed Thu May 21
• Flow and algorithm PollResize and RunTick integration. article Standard Reviewed Thu May 21
• Verification and traceability Resize channel tests and platform extern anchors. article Standard Reviewed Thu May 21

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Completeness

OKfeature · 3 SpecSection(s) · 1 H2 heading(s)

Section id	Required	Found
what-this-feature-specifies	yes	yes
implementation-anchors	yes	yes

Full tree: run pnpm verify:platform-spec-layout (writes src/generated/platform-spec-layout-report.json).

Related spec docs

• Feature
  Console terminal events

  Parent feature hub

Purpose

Document design model for the Console Terminal Events feature: role-specific normative detail beyond the feature hub.

Canonical references

• Feature hub: Console Terminal Events
• Sibling articles in this bundle (design model, contracts, flow, examples, verification)

Detailed behavior

ConsoleMessage

Variant	Payload	Use
Resize(ConsoleSize)	columns/rows	Terminal geometry changed
(tick-related)	—	Integrated with Console.RunTick polling

Messages flow on an unbounded Channel<ConsoleMessage> created by Console.MessagesChannel() unless callers supply their own channel.

OnResize hub

Same-fiber event OnResize(ConsoleSize) with cached lastSize. Distinct from Concurrency.Hub (channel multiplexing). Use when resize handlers must run on the UI fiber without cross-fiber Send.

Size probing stack

flowchart TD
  winsize[Platform Winsize ioctl]
  env[COLUMNS / LINES env]
  query[Terminal.QuerySize]
  winsize --> query
  env --> query

ANSI screen modes are unrelated to size events; see ANSI escape model.

Verification

See the verification and traceability article in this bundle and compiler/corelib/beskid_corelib/tests/corelib_tests/src/console/.

Related topics

• Parent feature hub and Terminal and console area