[Fix #1174] Event source auto-generated by runtime implementations

[ricardozanini]

Summary

• Clarify that runtime implementations generate the event source at emission time (e.g., from the workflow identity /{namespace}/{name}/{version}) when not explicitly provided
• When the workflow author supplies a value, it takes precedence over the auto-generated one
• Consistent with the id auto-generation pattern from [Fix #1167] Clarify event id is auto-generated by runtime #1168

Fixes #1174

Test plan

• Verify dsl-reference.md event properties table reflects auto-generation and override behavior
• Verify schema/workflow.yaml EventSource description is updated

[Copilot]

Pull request overview

Updates the specification documentation to clarify that emitted event source values can be auto-generated by runtime implementations at emission time (typically derived from the workflow identity) unless the workflow author explicitly provides one.

Changes:

• Clarify EventSource behavior in schema/workflow.yaml to note runtime generation when omitted.
• Update the DSL reference event properties table to describe runtime-generated source and author override semantics.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
schema/workflow.yaml	Updates EventSource description to document runtime auto-generation when not provided.
dsl-reference.md	Updates the event properties table to clarify runtime-generated source and override behavior.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

dsl-reference.md:2141

• The note still starts with “Required when emitting…”, which can be read as requiring workflow authors to provide source even though the table marks it as not required and the text says runtimes generate it when omitted. Rephrasing to “If not explicitly provided…” would make the override/default behavior clearer.

| source | `string` | `no` | An URI formatted string, or [runtime expression](dsl.md#runtime-expressions), that identifies the context in which an event happened. `source` + `id` is unique for each distinct event.<br>*Required when emitting an event using `emit.event.with`, generated by runtime implementations (e.g., from the workflow identity `/{namespace}/{name}/{version}`) at emission time. When explicitly provided by the workflow author, the supplied value takes precedence over the auto-generated one.* |

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

dsl-reference.md:2141

• Grammar/wording: "An URI formatted string" should be "A URI-formatted string" (also used elsewhere in this table), and the hyphenation reads more cleanly.

| source | `string` | `no` | An URI formatted string, or [runtime expression](dsl.md#runtime-expressions), that identifies the context in which an event happened. `source` + `id` is unique for each distinct event.<br>*Required when emitting an event using `emit.event.with`, generated by runtime implementations (e.g., from the workflow identity `/{namespace}/{name}/{version}`) at emission time. When explicitly provided by the workflow author, the supplied value takes precedence over the auto-generated one.* |

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

dsl-reference.md:2141

• This note is internally contradictory: it starts with “Required when emitting …” but then says runtimes generate source when it’s not explicitly provided. Rephrasing to “when emitting … if not provided, generated …” would be clearer and consistent with the auto-generation behavior being documented.

| source | `string` | `no` | An URI formatted string, or [runtime expression](dsl.md#runtime-expressions), that identifies the context in which an event happened. `source` + `id` is unique for each distinct event.<br>*Required when emitting an event using `emit.event.with`, generated by runtime implementations (e.g., from the workflow identity `/{namespace}/{name}/{version}`) at emission time. When explicitly provided by the workflow author, the supplied value takes precedence over the auto-generated one.* |

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

dsl-reference.md:2141

• The source property description is a bit contradictory/unclear: it says "Required when emitting" but also says runtimes generate it when not explicitly provided. Also, "An URI formatted" is grammatically incorrect.

Consider rephrasing this note to make it clear that source is optional for authors (the runtime supplies a default when omitted), and fix the URI wording.

| source | `string` | `no` | An URI formatted string, or [runtime expression](dsl.md#runtime-expressions), that identifies the context in which an event happened. `source` + `id` is unique for each distinct event.<br>*Required when emitting an event using `emit.event.with`, generated by runtime implementations (e.g., from the workflow identity `/{namespace}/{name}/{version}`) at emission time. When explicitly provided by the workflow author, the supplied value takes precedence over the auto-generated one.* |