Add MarshalText to types.Date - #162
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Date defines UnmarshalText, which parses the "2006-01-02" DateFormat, but
has no MarshalText, so it inherits time.Time's RFC 3339 one. Every codec
that pairs encoding.TextMarshaler with encoding.TextUnmarshaler therefore
writes a Date it cannot read back:
xml.Marshal -> <date>2019-04-01T00:00:00Z</date>
xml.Unmarshal -> parsing time "2019-04-01T00:00:00Z": extra text: "T00:00:00Z"
Format with DateFormat instead, matching MarshalJSON, String and
UnmarshalText, and matching the method set types.Duration already carries.
This also resolves the XML round trip that oapi-codegen#58 addressed with MarshalXML
and UnmarshalXML, without needing the encoding/xml import.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Problem
types.DatedefinesUnmarshalText, which parses theDateFormatlayout (2006-01-02), but it defines noMarshalText. It therefore inheritstime.Time's, which emits RFC 3339. The two halves ofencoding.TextMarshaler/encoding.TextUnmarshalerdisagree, so any codec that pairs them writes aDateit cannot read back.encoding/xmlshows it with no third-party dependency:The same thing happens in any other text-based encoder. I hit it originally through a DynamoDB mapper (
guregu/dynamo), which selectsTextMarshalerto encode andTextUnmarshalerto decode: rows written with a date field could never be read back.Fix
Add
MarshalText, formatting withDateFormatso it agrees withMarshalJSON,StringandUnmarshalText. This is also the method settypes.Durationalready carries (MarshalJSON/UnmarshalJSON,MarshalText/UnmarshalText,Bind,String) —Datewas missing exactly one method from it.Relationship to #58
#58 fixed the XML symptom with
MarshalXML/UnmarshalXML(42 lines plus anencoding/xmlimport) and was closed by its author without review. FixingMarshalTextresolves that round trip at the root, in three lines, with no new import — and fixes every other text-based encoder at the same time. Tests here cover the XML case so that behaviour stays pinned.Compatibility
This is an observable behaviour change for anyone relying on
Dateemitting RFC 3339 through a text encoder. I'd argue that output was never usable, sinceUnmarshalTextrejects it, but flagging it explicitly so it's a deliberate call rather than a surprise. JSON output is unaffected.Testing
TestDate_MarshalText,TestDate_TextRoundTrip,TestDate_XMLRoundTripadded.go test ./...); no existing test depended on the RFC 3339 text output.golangci-lintv2.12.2 (the version CI pins) reports 0 issues ontypes/.