Recommend that order of unordered collections is maintained where possible

At a glance

• Identifier: #1092
• Stage: RFC2: Draft
• Champion: @benjie
• PR: Recommend that order of unordered collections is maintained where possible
• Related:
  • #1091 (Define Data Collections used in the spec)
  • #1102 (Define Data Collections used in the spec)

Timeline

• Added to 2024-06-06 WG agenda
• Spec PR created on 2024-04-05 by benjie
• Commit pushed: Add recommendation to preserve order where possible on 2024-04-05 by @benjie

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For legibility and consistency reasons, it's helpful if the order of unordered collections is maintained. For example, an enum describes a set (unordered) of possible values, but it would be irritating if every time you introspected the API or built an SDL for it the enum values were in a different (random) order. This PR recommends that you maintain the initial order that such unordered collections were created with. Theoretically, this means that if you generate SDL from a schema (e.g. via introspection) and then build a new cloned schema from this SDL, generating SDL from this cloned schema (e.g. via introspection) should match the original SDL (i.e. printSchema(schema) == printSchema(buildClientSchema(introspectionFromSchema(schema))))

This PR builds on #1091 and is a change extracted from #1063 as discussed at last night's WG meeting. It does need to be stacked since it also adds the ordering details to Appendix A (originally we thought it might be able to be separate).

The previous PR in this stack is:

• #1102

The next PR in this stack is:

• #1063