(iceberg-go) branch main updated: fix data race in yieldDataFiles (#650)

[zeroshade]

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zeroshade pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/iceberg-go.git


The following commit(s) were added to refs/heads/main by this push:
     new c66aacd4 fix data race in yieldDataFiles (#650)
c66aacd4 is described below

commit c66aacd4d2e0ad4671c7671d0aac8f465ec7d7e3
Author: Vincent Janelle <vjane...@users.noreply.github.com>
AuthorDate: Mon Dec 22 08:01:34 2025 -0800

    fix data race in yieldDataFiles (#650)
    
    The err variable was being written by a goroutine (lines 157-158)
    while simultaneously being read by the iterator (lines 168, 173).
    
    Use a channel to defer reading the error until after the goroutine
    completes and the output channel is closed.
---
 table/partitioned_fanout_writer.go | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/table/partitioned_fanout_writer.go 
b/table/partitioned_fanout_writer.go
index d0c366af..838513f5 100644
--- a/table/partitioned_fanout_writer.go
+++ b/table/partitioned_fanout_writer.go
@@ -151,11 +151,15 @@ func (p *partitionedFanoutWriter) fanout(ctx 
context.Context, inputRecordsCh <-c
 }
 
 func (p *partitionedFanoutWriter) yieldDataFiles(fanoutWorkers 
*errgroup.Group, outputDataFilesCh chan iceberg.DataFile) 
iter.Seq2[iceberg.DataFile, error] {
-       var err error
+       // Use a channel to safely communicate the error from the goroutine
+       // to avoid a data race between writing err in the goroutine and 
reading it in the iterator.
+       errCh := make(chan error, 1)
        go func() {
                defer close(outputDataFilesCh)
-               err = fanoutWorkers.Wait()
+               err := fanoutWorkers.Wait()
                err = errors.Join(err, p.writers.closeAll())
+               errCh <- err
+               close(errCh)
        }()
 
        return func(yield func(iceberg.DataFile, error) bool) {
@@ -164,13 +168,15 @@ func (p *partitionedFanoutWriter) 
yieldDataFiles(fanoutWorkers *errgroup.Group,
                        }
                }()
 
+               // Yield data files as they arrive - no error yet since 
goroutine is still running
                for f := range outputDataFilesCh {
-                       if !yield(f, err) {
+                       if !yield(f, nil) {
                                return
                        }
                }
 
-               if err != nil {
+               // Channel is closed, now safe to read the error
+               if err := <-errCh; err != nil {
                        yield(nil, err)
                }
        }