FileChunkProducer.shouldProduceMore updates state

[rnro]

Motivation:

FileChunkProducer would not reflect its internal state when requested to produce more elements for the sequence after being paused.

Modifications:

FileChunkProducer.shouldProduceMore updates the internal state and returns the threadpool leading to more elements being produced.

Result:

FileChunkProducer should no longer hang after being paused.

[rnro]

Should resolve #2887

[finagolfin]

This fixes the test hangs, but I now see randomly failing tests, particularly when run in parallel:

> ../swift-6.0-RELEASE-fedora39/usr/bin/swift test --filter FileHandleTests  --parallel
Building for debugging...                                                                                                                                          [1/1] Write swift-version-649633EA72C13463.txt                                                                                                                     Build complete! (0.22s)                                                                                                                                            [63/63] Testing NIOFileSystemIntegrationTests.FileHandleTests/testWriteSequenceOfBytes
Test Suite 'Selected tests' started at 2024-09-19 14:54:16.337
Test Suite 'FileHandleTests' started at 2024-09-19 14:54:16.338
Test Case 'FileHandleTests.testReadEndOffsetExceedsEOFClosedrange' started at 2024-09-19 14:54:16.338
/home/finagolfin/swift-nio/Tests/NIOFileSystemIntegrationTests/FileHandleTests.swift:492: error: FileHandleTests.testReadEndOffsetExceedsEOFClosedrange : XCTAssertEqual failed: ("[2f2f3d3d3d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d...6f6e732077652075736520666f722074656d706f726172792066696c65732e0a](6784 bytes)") is not equal to ("[2f2f3d3d3d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d...722e636f64652c202e636c6f736564290a202020207d0a7d0a23656e6469660a](54324 bytes)") -
Test Case 'FileHandleTests.testReadEndOffsetExceedsEOFClosedrange' failed (0.004 seconds)
Test Suite 'FileHandleTests' failed at 2024-09-19 14:54:16.343
         Executed 1 test, with 1 failure (0 unexpected) in 0.004 (0.004) seconds                                                                                   Test Suite 'Selected tests' failed at 2024-09-19 14:54:16.343
         Executed 1 test, with 1 failure (0 unexpected) in 0.004 (0.004) seconds
                                                                                                                                                                   Test Suite 'Selected tests' started at 2024-09-19 14:54:16.344
Test Suite 'FileHandleTests' started at 2024-09-19 14:54:16.345
Test Case 'FileHandleTests.testReadEndOffsetExceedsEOFPartialThrough' started at 2024-09-19 14:54:16.345
/home/finagolfin/swift-nio/Tests/NIOFileSystemIntegrationTests/FileHandleTests.swift:492: error: FileHandleTests.testReadEndOffsetExceedsEOFPartialThrough : XCTAssertEqual failed: ("[2f2f3d3d3d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d...696f6e54696d652c2046696c65496e666f2e54696d6573706563287365636f6e](51072 bytes)") is not equal to ("[2f2f3d3d3d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d...722e636f64652c202e636c6f736564290a202020207d0a7d0a23656e6469660a](54324 bytes)") -                                                                                                                                                         Test Case 'FileHandleTests.testReadEndOffsetExceedsEOFPartialThrough' failed (0.016 seconds)
Test Suite 'FileHandleTests' failed at 2024-09-19 14:54:16.361
         Executed 1 test, with 1 failure (0 unexpected) in 0.016 (0.016) seconds                                                                                   Test Suite 'Selected tests' failed at 2024-09-19 14:54:16.361
         Executed 1 test, with 1 failure (0 unexpected) in 0.016 (0.016) seconds

Test Suite 'Selected tests' started at 2024-09-19 14:54:16.356                                                                                                     Test Suite 'FileHandleTests' started at 2024-09-19 14:54:16.357
Test Case 'FileHandleTests.testReadEndOffsetExceedsEOFPartialUpTo' started at 2024-09-19 14:54:16.357
/home/finagolfin/swift-nio/Tests/NIOFileSystemIntegrationTests/FileHandleTests.swift:492: error: FileHandleTests.testReadEndOffsetExceedsEOFPartialUpTo : XCTAssertEqual failed: ("[2f2f3d3d3d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d...72794469726563746f72792874656d706c6174653a2022746573742d58585822](12800 bytes)") is not equal to ("[2f2f3d3d3d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d2d...722e636f64652c202e636c6f736564290a202020207d0a7d0a23656e6469660a](54324 bytes)") -
Test Case 'FileHandleTests.testReadEndOffsetExceedsEOFPartialUpTo' failed (0.006 seconds)
Test Suite 'FileHandleTests' failed at 2024-09-19 14:54:16.363                                                                                                              Executed 1 test, with 1 failure (0 unexpected) in 0.006 (0.006) seconds                                                                                   Test Suite 'Selected tests' failed at 2024-09-19 14:54:16.363
         Executed 1 test, with 1 failure (0 unexpected) in 0.006 (0.006) seconds

[rnro]

Hi @finagolfin thanks for following up on this, I was seeing this too in my testing. I've proposed that we revert the change for now and circle-back #2892.