fix: let explicit @Schema(format) override type-derived format (#5185)

[seonwooj0810]

Fixes #5185

Problem

When a field carries an explicit @Schema(format = "...") whose owning type already resolves to a built-in format, the explicit format is silently dropped. The reported case is java.net.URI annotated with @Schema(format = "uri-reference"): the type resolves to format: uri first, and because the schema already has a (type-derived) format, the explicit override is ignored — producing format: uri instead of the requested uri-reference.

@Schema#format is documented as "Provides an optional override for the format", so an explicitly supplied format should win over the one inferred from the property type.

Change

In ModelResolver.resolveSchemaMembers(...) the format was only applied when the schema did not already have one:

if (StringUtils.isNotBlank(format) && StringUtils.isBlank(schema.getFormat())) {
    schema.format(format);
}

This is relaxed so that a non-blank explicit format always takes precedence over a type-derived format:

if (StringUtils.isNotBlank(format)) {
    schema.format(format);
}

This fixes the uri-reference case in #5185 and any other type whose explicit @Schema(format) differs from its inferred format, without needing a per-type enum entry. A field with no explicit @Schema(format) still falls back to the type-derived format (e.g. plain URI → uri).

Tests

Added Ticket5185Test covering both OpenAPI 3.0 and 3.1 resolution:

• @Schema(format = "uri-reference") URI resolves to format: uri-reference
• a plain URI (no annotation) still resolves to format: uri

Test evidence

Tests run: 2, Failures: 0, Errors: 0, Skipped: 0 -- in io.swagger.v3.core.resolving.Ticket5185Test

Full swagger-core module suite after the change:

Tests run: 689, Failures: 0, Errors: 0, Skipped: 0
BUILD SUCCESS

Verification done: (1) No in-flight PR — gh pr list --search "5185" / "uri-reference" returned none; no open PR touches this path. (2) No active claim — issue is unassigned and has no claim comments. (3) Code-focused — change is in ModelResolver.java plus a Java test. (4) Bug still present on master — the guarded condition is unchanged at ModelResolver line 3184. (5) No parent epic closing this. Branch is based directly on current master (no rebase needed).

Note: the issue suggested adding a dedicated URI_REFERENCE PrimitiveType enum entry. This PR instead fixes the root cause — explicit @Schema(format) should always override the inferred format — which covers uri-reference and any future explicit-override case with a smaller, more general change. Happy to switch to the enum-based approach if maintainers prefer it.