Upgrade okhttp to 5.1.0

[ArnyminerZ]

There were some things changed on MockWebServer. Mainly that MockResponse now is immutable, so MockResponse.Builder exists; some function names have been changed.

Also Response.body now is never null, so in order to check whether a body has been set or not, I've checked whether the response length is 0, and whether it has a content type. If none of this conditions apply, body is not set. This is done like this instead of simply checking for content length because when content type is not set we automatically assume it's XML.

[rfc2822]

Very cool!

Is it possible to keep API the same (assertMultiStatus not inline / without body, it's purpose is just to throw an Exception if needed)?

When it's ready, please request review from @sunkup.

[Copilot]

Pull Request Overview

Updates the project to use OkHttp 5.1.0 and migrates MockWebServer tests to the new immutable MockResponse.Builder API, replaces shutdown() with close(), and adds logic in DavResource to detect empty response bodies.

• Migrate tests to mockwebserver3.MockResponse.Builder and update assertions to use new APIs.
• Add isEmptyResponseBody helper in DavResource to handle non-null Response.body.
• Validate and adjust multi-status responses in DavResource.

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

File	Description
src/test/kotlin/at/bitfire/dav4jvm/...	Tests updated to use MockResponse.Builder and close().
src/main/kotlin/at/bitfire/dav4jvm/DavResource.kt	Added isEmptyResponseBody and adjusted assertMultiStatus.
gradle/libs.versions.toml	Upgraded okhttp and mockwebserver artifact versions.

Comments suppressed due to low confidence (1)

src/main/kotlin/at/bitfire/dav4jvm/DavResource.kt:734

• [nitpick] Method name isEmptyResponseBody suggests it returns true when the body is empty, but its doc and logic return true when a body is present. Consider renaming this method to hasResponseBody or inverting its return values to match its name and documentation.

    private fun isEmptyResponseBody(response: Response): Boolean {

[sunkup]

Yup. Looks good

[rfc2822]

Very nice! Some comments:

1. In assertMultiStatus, we have

val firstBytes = ByteArray(XML_SIGNATURE.size)
body.source().peek().readFully(firstBytes)

There's now response.peekBody(size) and we can directly use its return value to check the XML signature:

response.peekBody(XML_SIGNATURE.size).use {
  // …
}

2. We have some httpResponse.body?. in the code. Body is now non-nullable, so we can remove the ?.