Fix JSON Close data race. (#8486)

The JSON stream library has no safe way of aborting while

Since we cannot expect the called to safely handle "Read" and "Close" calls we must handle this.

Also any Read error returned from upstream will crash the server. We preserve the errors and instead always return io.EOF upstream, but send the error on Close.

`readahead v1.3.1` handles Read after Close better.

Updates to `progressReader` is mostly to ensure safety.

Fixes #8481

pkg/s3select/progress.go

@@ -18,8 +18,10 @@ package s3select
 
 import (
 	"compress/bzip2"
+	"errors"
 	"fmt"
 	"io"
+	"sync"
 	"sync/atomic"
 
 	gzip "github.com/klauspost/pgzip"
@@ -50,13 +52,29 @@ type progressReader struct {
 	rc              io.ReadCloser
 	scannedReader   *countUpReader
 	processedReader *countUpReader
+
+	closedMu sync.Mutex
+	closed   bool
 }
 
 func (pr *progressReader) Read(p []byte) (n int, err error) {
+	// This ensures that Close will block until Read has completed.
+	// This allows another goroutine to close the reader.
+	pr.closedMu.Lock()
+	defer pr.closedMu.Unlock()
+	if pr.closed {
+		return 0, errors.New("progressReader: read after Close")
+	}
 	return pr.processedReader.Read(p)
 }
 
 func (pr *progressReader) Close() error {
+	pr.closedMu.Lock()
+	defer pr.closedMu.Unlock()
+	if pr.closed {
+		return nil
+	}
+	pr.closed = true
 	return pr.rc.Close()
 }