Several `ByteBuffer.array()` calls don't check `hasArray()` and ignore position/limit

[haskiindahouse]

A handful of code paths in client4 call ByteBuffer.array() directly. Two problems:

1. array() throws UnsupportedOperationException for direct buffers and ReadOnlyBufferException for read-only buffers. So a ByteBufferBody backed by ByteBuffer.allocateDirect(...) crashes inside forceBodyAsString/forceBodyAsByteArray and friends.
2. Even on a heap buffer, array() returns the entire backing storage and ignores position/limit. A partially-consumed buffer comes back wrong.

There's already a correct helper in Compressor.byteBufferToArray — it just isn't used in these spots.

Reproducer (no sttp dep needed for the JDK-level demo):

//> using scala 3.8.3

import java.nio.ByteBuffer

@main def run(): Unit =
  // direct buffer -> .array() throws
  val direct = ByteBuffer.allocateDirect(10)
  direct.put("hello".getBytes); direct.flip()
  try direct.array()
  catch case e: UnsupportedOperationException => println(s"direct: ${e.getClass.getSimpleName}")

  // partial heap buffer -> .array() returns wrong slice
  val partial = ByteBuffer.wrap("ABCDE".getBytes)
  partial.position(2); partial.limit(4) // remaining = "CD"
  println(s"partial.array() = '${new String(partial.array())}'") // "ABCDE", expected "CD"

Output:

direct: UnsupportedOperationException
partial.array() = 'ABCDE'

Source — call sites that need hasArray + slice handling:

• sttp/core/src/main/scala/sttp/client4/internal/package.scala

  Line 46 in 6b817f7

  ): Queue[Array[Byte]] = queue.enqueue(bytes.array())

• sttp/core/src/main/scala/sttp/client4/testing/package.scala

  Line 16 in 6b817f7

  case ByteBufferBody(b, _) => new String(b.array())

• sttp/core/src/main/scala/sttp/client4/testing/package.scala

  Line 33 in 6b817f7

  case ByteBufferBody(b, _) => b.array()

• sttp/core/src/main/scala/sttp/client4/internal/DigestAuthenticator.scala

  Line 168 in 6b817f7

  case ByteBufferBody(b, _) => b.array()

The standard pattern (mirrors what Compressor.byteBufferToArray does):

def toArray(b: ByteBuffer): Array[Byte] =
  if b.hasArray && b.arrayOffset == 0 && b.position == 0 && b.remaining == b.array.length then
    b.array
  else
    val out = new Array[Byte](b.remaining)
    b.duplicate.get(out)
    out

The DigestAuthenticator hit is the practical one — auth-int digest of a direct-buffer body throws instead of hashing. Happy to PR consolidating the call sites onto a single helper.

[adamw]

Thanks for the report - PRs welcome!