Synchronize strict servers

[mromaszewicz]

Bring the fiber and iris strict-server interface templates back into parity with the canonical stdhttp template (strict-interface.tmpl). Four pieces of drift were addressed:

1. Nullable / optional response-header serialization. Both templates now use the same three-way switch on .IsNullable / .IsOptional / default that PR support optional/nullable response headers #2301 introduced for stdhttp, so unspecified nullable values and nil optional pointers are skipped instead of being stringified into the wire header.

2. Response-header struct field types. The {{$opid}}{{$statusCode}}ResponseHeaders struct now uses {{.GoTypeDef}} (pointer/nullable-aware) rather than the raw {{.Schema.TypeDecl}}, matching the type that the typed-body Visit function expects.

3. $ref Text responses. The fixed-status-code + ref branch now matches Multipart and Text together (PR fix(strict-server): generate correct type for $ref text responses  #2225), so $ref text responses alias directly to the component response type. Iris additionally drops its unconditional type X string short-circuit, which previously masked $ref, $hasHeaders, and $fixedStatusCode for any text response.

4. $ref name qualification (fiber only). Switch from ucFirst to ucFirstWithPkgName so external-ref response types carry their package qualifier, matching stdhttp and iris.

Regenerated fixtures under internal/test/strict-server/{fiber,iris}/server.gen.go demonstrate the change for items (1) and (2); items (3) and (4) have no existing fiber/iris fixture coverage.

The no-content Visit*Response branch still renders headers unconditionally in all three templates (including stdhttp); that gap is tracked separately (#2349) and not addressed here.

Fixes: #2331

[greptile-apps]

Greptile Summary

This PR synchronizes the fiber and iris strict-server interface templates with the canonical strict-interface.tmpl (stdhttp), fixing four areas of drift: nullable/optional response-header serialization, header struct field types (GoTypeDef instead of Schema.TypeDecl), $ref text-response aliasing, and package-qualified external ref names for fiber. The generated fixture diffs for items (1) and (2) look correct and appropriately scoped; items (3) and (4) have no existing fixture coverage, as the PR acknowledges.

Confidence Score: 4/5

Safe to merge; all findings are P2 — the breaking field-type change is intentional and fixes a bug, but warrants release-note callout.

All findings are P2: the string → *string field type change is a compile-breaking change for downstream users (custom rule §3) but is fixing an incorrect prior behavior; the no-content header branch inconsistency is pre-existing and tracked in #2349; missing fixture coverage for the iris text $ref path is acknowledged by the author. No logic errors or security issues found.

No files require special attention; the template changes look structurally correct and match stdhttp.

Important Files Changed

Filename	Overview
pkg/codegen/templates/strict/strict-fiber-interface.tmpl	Brings fiber strict interface into parity with stdhttp: switches to ucFirstWithPkgName, GoTypeDef for header fields, adds nullable/optional header guard, and extends the $ref alias branch to Text responses. Breaking change for users with nullable/optional header fields (string → *string).
pkg/codegen/templates/strict/strict-iris-interface.tmpl	Brings iris strict interface into parity with stdhttp: removes the unconditional type X string text-response short-circuit, uses GoTypeDef, adds nullable/optional header guards, and extends the $ref alias branch to Text responses. No fixture coverage for the text $ref path.
internal/test/strict-server/fiber/server.gen.go	Regenerated correctly: NullableHeader/OptionalHeader changed from string to *string and Visit function now checks for nil before setting headers. Diff scope matches the stated change.
internal/test/strict-server/iris/server.gen.go	Regenerated correctly: same nullable/optional header changes as fiber. Diff scope matches the stated change.

Comments Outside Diff (1)

1. pkg/codegen/templates/strict/strict-iris-interface.tmpl, line 162-181 (link)

   No-content Visit*Response branch still emits headers unconditionally

   The no-content Visit*Response branch still calls Header().Set(...) for every header without checking IsNullable / IsOptional, meaning nullable unspecified headers are serialized as their zero-value string. The same gap exists in the fiber and stdhttp templates (tracked in Strict-server: no-content Visit*Response skips nullable/optional header gating #2349). This PR brings the body-bearing branches into parity but the no-content branch remains inconsistent within the same template.

_{Reviews (1): Last reviewed commit: "Synchronize strict servers" | Re-trigger Greptile}