diene_interfaces

The Diene family's shared, implementation-free boundaries between portable Dart code and the host: process/clock (System), filesystem (Vfs), process execution and stdio (Terminal), and the two telemetry emit seams (LoggerSink, MetricsCollector).

Every fallible member returns Result from diene_result and never throws to communicate an expected failure. The error channel is the canonical RFC 9457 Problem from diene_problems, whose type URI is minted by the single C0 §2 builder.

import 'package:diene_interfaces/diene_interfaces.dart';
import 'package:diene_result/diene_result.dart';

// Depend on the narrow seam you need, not on dart:io.
Future<Result<String>> loadConfig(Vfs vfs, String path) => vfs.readText(path);

// In tests, use the shipped in-memory fakes — no mocking framework needed.
import 'package:diene_interfaces/test_helper.dart';

final InMemoryVfs vfs = InMemoryVfs(
  files: <String, List<int>>{'/etc/app.yaml': 'landscape: lapras'.codeUnits},
);
final String text = (await vfs.readText('/etc/app.yaml')).unwrap();

Public surface

Supporting types: VfsEntry / VfsEntryType / VfsStat, TerminalCommand / TerminalOutput / TerminalWrite / TerminalRead / TerminalChannel, LogRecord / LogLevel, MetricRecord / MetricKind, and TelemetryAttributes.

Failure vocabulary: PortName, PortErrorCode, portProblem, portFailure, invalidInput.

Validators an implementation may reuse: checkVfsPath, checkTerminalCommand, checkTerminalOutput, checkTerminalWrite, checkTerminalRead, checkLogRecord, checkMetricRecord, checkTelemetryAttributes.

What this package deliberately does NOT own

• No trace seam. Trace test interfaces stay language-local (RB-19).
• No OTel implementer or exporter. Dart/Flutter telemetry rides Faro at runtime through the frontend machinery.
• No concrete dart:io or Flutter implementation. This is the seam package; real adapters live in the consuming application layer.

TestHelper

package:diene_interfaces/test_helper.dart ships stateful in-memory fakes for all five seams (InMemorySystem, InMemoryVfs, InMemoryTerminal, InMemoryLoggerSink, InMemoryMetricsCollector) plus expectPortProblem and SeamAssertionFailure. It depends on no test framework, matcher library, mocking package, Flutter, or exporter, so it adds nothing to a consumer's production dependency graph. Every fallible member accepts FIFO scripted results, so failure paths are exercised without exceptions.

Read the package doc for the seam contracts, the S33 extraction boundary, and the documented parity deltas against the @atomicloud/diene.interfaces Bun sibling.

Development

• pls setup resolves the workspace dependencies.
• pls test runs the unit, C0 conformance, and TestHelper meta suites.
• pls test:coverage enforces the separate unit and meta ledgers.
• pls deadcode runs the repository and production-only dead-code passes.
• pls package:validate runs the release guard, publish dry-run, and pana.