feat(binder)!: build a command from attached input sources - #196
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Restructure the request binder so it builds a command or query from independently attached sources rather than from a single DTO. The binder is source-agnostic and untyped: it is entered from its failure envelope — Bind.Request(envelope) — and a DTO's properties (PropertiesOf(dto)) and individually named, source-tagged out-of-DTO arguments (Argument(name).From(source, value) / ArgumentList, with FromRoute/FromQuery/... sugar) are attached as peers, sharing one collect-all envelope and one set of argument paths. The command type is named only at the New<TCommand>/Create<TCommand> terminal, inferred from the assembler; a single RequestBinder type serves top-level and nested binding, and a nested complex binding receives that RequestBinder plus the sub-DTO, so its result type is inferred with no explicit type argument. An argument's provenance is captured in the failure context under the new public RequestArgumentSource key (the argument-path key is public too), so an adapter can project a structured per-field response; a DTO property carries no source (its provenance is implicit). The request-binder guide (EN/FR) and the package README are rewritten to the new model, and ADR-0021 records the decision. BREAKING CHANGE: the entry point changes from Bind.PropertiesOf(dto).FailWith(env) to Bind.Request(env) + bind.PropertiesOf(dto); the property selectors move to PropertySource; the terminals New/Create carry the command type parameter; the converter types drop their TRequest type parameter; nested-binding functions take a non-generic RequestBinder and the sub-DTO. Pre-release, no external consumers. Refs: #148 Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01J12ghrzM1xiAKw4LETJDqr
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Summary
Restructure the request binder so it builds a command or query from independently attached input sources rather than from a single DTO, and bind out-of-DTO arguments (route/query/header/…) as peers of the DTO's properties — the feature requested in #148. The binder becomes source-agnostic and untyped: it is entered from its failure envelope (
Bind.Request(envelope)), and the command type is named only at theNew/Createterminal.Type of change
Changes
Bind.Request(envelope)/Bind.WithOptions(...).Request(envelope)return a non-genericRequestBinder; a DTO is attached withbind.PropertiesOf(dto)(→PropertySource<TDto>) and out-of-DTO values withbind.Argument(name)/bind.ArgumentList(name).Argument(name).From(source, value), withFromRoute/FromQuery/FromHeader/FromBody/FromFormsugar (scalar and list), bound with the same converter surface as DTO properties.RequestArgumentSourcekey; the argument-path key is public too (RequestBindingError.ArgumentPathKey/ArgumentSourceKey). A DTO property carries no source (its provenance is implicit).New/Createnow carry the command type parameter, inferred from the assembler; a singleRequestBindertype serves top-level and nested binding; nested-binding functions take(RequestBinder, TDto)— no explicit type argument at the call site.TRequesttype parameter; value-type argument overloads (where T : struct) mirror the value-type property overloads.README.nuget.mdupdated to the new entry.Testing
dotnet build FirstClassErrors.sln— 0 warnings, 0 errorsdotnet test FirstClassErrors.sln— 1070 passed, 0 failedFirstClassErrors.Analyzers.UnitTests) — ran as part of the full-solution testDocumentation
doc/updated (request-binder guide EN/FR,README.nuget.md)RequestBinder.fr.mdwas kept in sync; the top-levelREADME.fr.mdreferences no changed behavior and needed no editArchitecture decisions
Proposed: ADR-0021 (bind out-of-DTO arguments as peers through a source-agnostic untyped entry)ADR-0021 records the entry-point change; the decisions of ADR-0007, ADR-0012 and ADR-0017 are unaffected — their illustrative
Bind.PropertiesOfsurface is now historical, left unedited per the ADR discipline (an accepted ADR is not edited in place).Related issues
Closes #148
🤖 Generated with Claude Code
https://claude.ai/code/session_01J12ghrzM1xiAKw4LETJDqr