feat(openapi3): add x-ms-duration extension support for duration encoding with round-trip via @extension decorator #9412

Copilot · 2026-01-19T19:16:24Z

OpenAPI duration property import with x-ms-duration extension

This PR implements support for duration types in the OpenAPI importer using the x-ms-duration extension, with round-trip capability via the @extension decorator.

Changes completed:

Implementation details:

Import (OpenAPI → TypeSpec):

Modified getNumberType() and getIntegerType() in generate-types.ts to check for x-ms-duration extension (values: seconds or milliseconds)
Updated getDurationSchemaDecorators() function in decorators.ts to:
- Accept effectiveType parameter to properly handle OpenAPI 3.1 type arrays like ["integer", "null"]
- Generate appropriate @encode decorators based on both the x-ms-duration value and the schema's format
- Support all integer formats (int8, int16, int32, int64, uint8, uint16, uint32, uint64) even when type is "number"
- Support all number formats (float, double, decimal, decimal128)
- Use effectiveType instead of schema.type to avoid defaulting to float32 when type is an array
Removed filtering of x-ms-duration from getExtensions() so it's also added as an @extension decorator for proper round-tripping

Export (TypeSpec → OpenAPI):

Round-tripping is achieved via the standard @extension decorator mechanism
When TypeSpec has @extension("x-ms-duration", "seconds"), the standard extension handling emits it to OpenAPI

Test coverage:

Added comprehensive test suite in data-types.test.ts covering all import scenarios from requirements table (33 tests)
Added test cases in generate-type.test.ts for inline type expressions (82 tests)
All tests pass successfully
Manual testing confirms correct encoding types for all formats (int8-uint64, float32, float64, decimal, etc.)

Supported scenarios:

OAS type	OAS format	OAS x-ms-duration	TypeSpec Output
string	duration	not applicable	`duration`
integer	int32	absent	`int32`
integer	int32	present, set to seconds	`@extension("x-ms-duration", "seconds") @encode("seconds", int32) ... duration`
number	int64	present, set to seconds	`@extension("x-ms-duration", "seconds") @encode("seconds", int64) ... duration`
number	float	absent	`float32`
number	float	present, set to seconds	`@extension("x-ms-duration", "seconds") @encode("seconds", float32) ... duration`
number	decimal	present, set to seconds	`@extension("x-ms-duration", "seconds") @encode("seconds", decimal) ... duration`
number	double	present, set to milliseconds	`@extension("x-ms-duration", "milliseconds") @encode("milliseconds", float64) ... duration`

Example transformations:

Integer type with int32 format:

# OpenAPI
DurationInt32Seconds:
  type: integer
  format: int32
  x-ms-duration: seconds

// TypeSpec
@extension("x-ms-duration", "seconds")
@encode("seconds", int32)
scalar DurationInt32Seconds extends duration;

Number type with int64 format:

# OpenAPI
DurationNumberInt64:
  type: number
  format: int64
  x-ms-duration: seconds

// TypeSpec
@extension("x-ms-duration", "seconds")
@encode("seconds", int64)
scalar DurationNumberInt64 extends duration;

Number type with decimal format:

# OpenAPI
DurationDecimalSeconds:
  type: number
  format: decimal
  x-ms-duration: seconds

// TypeSpec
@extension("x-ms-duration", "seconds")
@encode("seconds", decimal)
scalar DurationDecimalSeconds extends duration;

Original prompt

This section details on the original issue you should resolve

<issue_title>importer - OpenAPI duration properties should result in a duration properties</issue_title>
<issue_description>### Clear and concise description of the problem

When importing a property with the following schema:
foo:
  type: number
  format: duration
Currently results in this
foo: numeric
But should result in this
@encode("seconds", float32)
foo: duration
Checklist

Follow our Code of Conduct

Read the docs.

Check that there isn't already an issue that request the same feature to avoid creating a duplicate.</issue_description>

<agent_instructions>use conventional commits.
run the formatting command before any commit.
start by writing the unit tests first.
when done, run the following command to add a feature entry to the changelog npx @chronus/chronus add</agent_instructions>

Comments on the Issue (you are @copilot in this section)

Fixes importer - OpenAPI duration properties should result in a duration properties #9411

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

…with @encode decorator Co-authored-by: baywet <7905502+baywet@users.noreply.github.com>

Co-authored-by: baywet <7905502+baywet@users.noreply.github.com>

baywet · 2026-01-19T19:40:47Z

@copilot add another unit test to validate there are no regressions if it does not exist already.

The following OpenAPI description

foo:
  type: string
  format: duration

Should result in this TypeSpec

bar: duration

Note there are no encode attribute in that case.

pkg-pr-new · 2026-01-19T19:42:54Z

Open in StackBlitz

npm i https://pkg.pr.new/microsoft/typespec/@typespec/openapi@9412

npm i https://pkg.pr.new/microsoft/typespec/@typespec/openapi3@9412

commit: 8772da4

Co-authored-by: baywet <7905502+baywet@users.noreply.github.com>

Copilot · 2026-01-19T19:47:02Z

@copilot add another unit test to validate there are no regressions if it does not exist already.

The following OpenAPI description
...

Added regression test in commit 09b3593. The test validates that type: string, format: duration converts to duration without an encode decorator, ensuring no regression from the number duration changes.

azure-sdk · 2026-01-19T20:05:00Z

You can try these changes here

🛝 Playground	🌐 Website	🛝 VSCode Extension

baywet · 2026-01-21T14:58:10Z

@copilot revert the change where the encode decorator generates the extension. Instead make sure the import also adds an extension decorator when the extension is present in the source document.

…d of auto-generating extension - Revert export functionality that auto-generated x-ms-duration extension - Update import to add @extension decorator when x-ms-duration is present - Both @extension and @encode decorators are now added during import - Removes extension filtering for x-ms-duration - Update tests to expect both decorators - Enables proper round-tripping via @extension decorator Co-authored-by: baywet <7905502+baywet@users.noreply.github.com>

Copilot · 2026-01-21T15:14:17Z

@copilot revert the change where the encode decorator generates the extension. Instead make sure the import also adds an extension decorator when the extension is present in the source document.

Reverted export functionality in commit 3eab35d. The importer now adds both @extension("x-ms-duration", "seconds") and @encode("seconds", int32) decorators when x-ms-duration is present in the OpenAPI source. This enables proper round-tripping using the @extension decorator instead of auto-generating the extension from @encode.

baywet · 2026-01-21T17:49:38Z

@copilot while running integration tests, I'm running into the following issue, regardless of the format, the encode as is always float32. Investigate and correct this behaviour.

…encoding format - Pass effectiveType to getDurationSchemaDecorators to handle OpenAPI 3.1 type arrays - Fixes issue where format was always float32 regardless of actual format - Update test expectations to match TypeSpec compiler's decorator ordering - Now correctly generates int32, float32, float64, decimal based on schema format Co-authored-by: baywet <7905502+baywet@users.noreply.github.com>

Copilot · 2026-01-21T18:23:16Z

@copilot while running integration tests, I'm running into the following issue, regardless of the format, the encode as is always float32. Investigate and correct this behaviour.

Fixed in commit 446c2e1. The issue was that getDurationSchemaDecorators was using schema.type directly, which fails for OpenAPI 3.1 type arrays like ["integer", "null"]. Now it uses effectiveType (the extracted non-null type) to correctly determine the encoding format. All formats (int32, float32, float64, decimal, etc.) now work correctly.

baywet · 2026-01-22T15:34:15Z

@copilot Add a data-types test for this format combination:

type: number
format: int64
x-ms-duration: seconds

The result should be @encode("seconds", int64) (and the type duration)
If the test fails, correct the implementation so it passes.

… with x-ms-duration - Add support for integer formats (int8, int16, int32, int64, uint8, uint16, uint32, uint64) when type is number - Fixes scenario where type: number, format: int64, x-ms-duration: seconds now correctly generates @encode("seconds", int64) - Add test case for number with int64 format and x-ms-duration extension - All 33 data-types tests pass Co-authored-by: baywet <7905502+baywet@users.noreply.github.com>

Copilot · 2026-01-22T15:41:42Z

@copilot Add a data-types test for this format combination:

...

Added test in commit 8772da4. The test initially failed (was generating @encode("seconds", float32) instead of @encode("seconds", int64)), so I updated the implementation to support all integer formats (int8-uint64) when the type is "number". The test now passes and correctly generates @encode("seconds", int64) for type: number, format: int64, x-ms-duration: seconds.

…ding with round-trip via @extension decorator (#9412) ## OpenAPI duration property import with x-ms-duration extension This PR implements support for duration types in the OpenAPI importer using the `x-ms-duration` extension, with round-trip capability via the `@extension` decorator. ### Changes completed: - [x] Add test cases for all duration scenarios with x-ms-duration extension - [x] Update getNumberType and getIntegerType functions to handle x-ms-duration extension (import) - [x] Add decorator generation for x-ms-duration with seconds/milliseconds encoding (import) - [x] Add @extension decorator for x-ms-duration to enable round-tripping - [x] Fix encoding type detection to use effectiveType (handles type arrays) - [x] Support integer formats (int8-uint64) for number type with x-ms-duration - [x] Run tests to validate all scenarios - [x] Format code before final commit - [x] Add changelog entry using chronus - [x] Add regression test for string duration format (no encode decorator) ### Implementation details: **Import (OpenAPI → TypeSpec):** - Modified `getNumberType()` and `getIntegerType()` in `generate-types.ts` to check for `x-ms-duration` extension (values: `seconds` or `milliseconds`) - Updated `getDurationSchemaDecorators()` function in `decorators.ts` to: - Accept `effectiveType` parameter to properly handle OpenAPI 3.1 type arrays like `["integer", "null"]` - Generate appropriate `@encode` decorators based on both the `x-ms-duration` value and the schema's format - Support all integer formats (int8, int16, int32, int64, uint8, uint16, uint32, uint64) even when type is "number" - Support all number formats (float, double, decimal, decimal128) - Use effectiveType instead of schema.type to avoid defaulting to float32 when type is an array - Removed filtering of `x-ms-duration` from `getExtensions()` so it's also added as an `@extension` decorator for proper round-tripping **Export (TypeSpec → OpenAPI):** - Round-tripping is achieved via the standard `@extension` decorator mechanism - When TypeSpec has `@extension("x-ms-duration", "seconds")`, the standard extension handling emits it to OpenAPI ### Test coverage: - Added comprehensive test suite in `data-types.test.ts` covering all import scenarios from requirements table (33 tests) - Added test cases in `generate-type.test.ts` for inline type expressions (82 tests) - All tests pass successfully - Manual testing confirms correct encoding types for all formats (int8-uint64, float32, float64, decimal, etc.) ### Supported scenarios: | OAS type | OAS format | OAS x-ms-duration | TypeSpec Output | | ---------- | ------------- | --------------------------- | ---------------- | | string | duration | not applicable | `duration` | | integer | int32 | absent | `int32` | | integer | int32 | present, set to seconds | `@extension("x-ms-duration", "seconds") @encode("seconds", int32) ... duration` | | number | int64 | present, set to seconds | `@extension("x-ms-duration", "seconds") @encode("seconds", int64) ... duration` | | number | float | absent | `float32` | | number | float | present, set to seconds | `@extension("x-ms-duration", "seconds") @encode("seconds", float32) ... duration` | | number | decimal | present, set to seconds | `@extension("x-ms-duration", "seconds") @encode("seconds", decimal) ... duration` | | number | double | present, set to milliseconds | `@extension("x-ms-duration", "milliseconds") @encode("milliseconds", float64) ... duration` | ### Example transformations: **Integer type with int32 format:** ```yaml # OpenAPI DurationInt32Seconds: type: integer format: int32 x-ms-duration: seconds ``` ```typespec // TypeSpec @extension("x-ms-duration", "seconds") @encode("seconds", int32) scalar DurationInt32Seconds extends duration; ``` **Number type with int64 format:** ```yaml # OpenAPI DurationNumberInt64: type: number format: int64 x-ms-duration: seconds ``` ```typespec // TypeSpec @extension("x-ms-duration", "seconds") @encode("seconds", int64) scalar DurationNumberInt64 extends duration; ``` **Number type with decimal format:** ```yaml # OpenAPI DurationDecimalSeconds: type: number format: decimal x-ms-duration: seconds ``` ```typespec // TypeSpec @extension("x-ms-duration", "seconds") @encode("seconds", decimal) scalar DurationDecimalSeconds extends duration; ```  <details> <summary>Original prompt</summary> > > ---- > > *This section details on the original issue you should resolve* > > <issue_title>importer - OpenAPI duration properties should result in a duration properties</issue_title> > <issue_description>### Clear and concise description of the problem > > When importing a property with the following schema: > > ```yaml > foo: > type: number > format: duration > ``` > > Currently results in this > > ```typespec > foo: numeric > ``` > > But should result in this > > ```typespec > @encode("seconds", float32) > foo: duration > ``` > > ### Checklist > > - [x] Follow our [Code of Conduct](https://github.com/microsoft/typespec/blob/main/CODE_OF_CONDUCT.md) > - [x] Read the [docs](https://typespec.io/docs/). > - [x] Check that there isn't already an issue that request the same feature to avoid creating a duplicate.</issue_description> > > <agent_instructions>use conventional commits. > run the formatting command before any commit. > start by writing the unit tests first. > when done, run the following command to add a feature entry to the changelog `npx @chronus/chronus add`</agent_instructions> > > ## Comments on the Issue (you are @copilot in this section) > > <comments> > </comments> > </details>  - Fixes #9411  --- ✨ Let Copilot coding agent [set things up for you](https://github.com/microsoft/typespec/issues/new?title=✨+Set+up+Copilot+instructions&body=Configure%20instructions%20for%20this%20repository%20as%20documented%20in%20%5BBest%20practices%20for%20Copilot%20coding%20agent%20in%20your%20repository%5D%28https://gh.io/copilot-coding-agent-tips%29%2E%0A%0A%3COnboard%20this%20repo%3E&assignees=copilot) — coding agent works faster and does higher quality work when set up for your repo. --------- Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: baywet <7905502+baywet@users.noreply.github.com> Co-authored-by: Vincent Biret <vibiret@microsoft.com>

Initial plan

0a944fe

Copilot AI assigned Copilot and baywet Jan 19, 2026

Copilot started work on behalf of baywet January 19, 2026 19:16 View session

Copilot AI and others added 2 commits January 19, 2026 19:27

feat(openapi3): convert number type with duration format to duration …

53b3f99

…with @encode decorator Co-authored-by: baywet <7905502+baywet@users.noreply.github.com>

chore: add changelog entry for duration format fix

7612221

Co-authored-by: baywet <7905502+baywet@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Fix importer to support OpenAPI duration properties~~ feat(openapi3): convert number type with duration format to duration with @encode decorator Jan 19, 2026

Copilot finished work on behalf of baywet January 19, 2026 19:35

Copilot AI requested a review from baywet January 19, 2026 19:35

Copilot started work on behalf of baywet January 19, 2026 19:41 View session

test(openapi3): add regression test for string duration format

09b3593

Co-authored-by: baywet <7905502+baywet@users.noreply.github.com>

Copilot finished work on behalf of baywet January 19, 2026 19:47

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baywet marked this pull request as ready for review January 19, 2026 19:49

baywet requested review from AlitzelMendez, bterlson, chrisradek, markcowl, timotheeguerin and witemple-msft as code owners January 19, 2026 19:49

baywet enabled auto-merge January 19, 2026 19:49

microsoft-github-policy-service bot added emitter:openapi3 Issues for @typespec/openapi3 emitter openapi3:converter Issues for @typespec/openapi3 openapi to typespec converter labels Jan 19, 2026

baywet marked this pull request as draft January 21, 2026 13:11

auto-merge was automatically disabled January 21, 2026 13:11
Pull request was converted to draft

Merge branch 'main' into copilot/fix-openapi-duration-properties

41e1207

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Copilot started work on behalf of baywet January 21, 2026 14:58 View session

Copilot AI changed the title ~~feat(openapi3): add bidirectional x-ms-duration extension support for duration encoding~~ feat(openapi3): add x-ms-duration extension support for duration encoding with round-trip via @extension decorator Jan 21, 2026

Copilot finished work on behalf of baywet January 21, 2026 15:15

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Merge branch 'main' into copilot/fix-openapi-duration-properties

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feat(openapi3): add x-ms-duration extension support for duration encoding with round-trip via @extension decorator #9412

feat(openapi3): add x-ms-duration extension support for duration encoding with round-trip via @extension decorator #9412

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feat(openapi3): add x-ms-duration extension support for duration encoding with round-trip via @extension decorator #9412

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OpenAPI duration property import with x-ms-duration extension

Changes completed:

Implementation details:

Test coverage:

Supported scenarios:

Example transformations:

Checklist

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