feat(storage): Takeover idempotence. (#13230)

cjc25 · web-flow · commit cc5d2a12293a · 2025-10-27T10:33:11.000-04:00
Takeovers at a specific object generation are safe to retry.
diff --git a/storage/writer.go b/storage/writer.go
@@ -272,6 +272,8 @@ func (w *Writer) openWriter() (err error) {
 	}
 
 	isIdempotent := w.o.conds != nil && (w.o.conds.GenerationMatch >= 0 || w.o.conds.DoesNotExist)
+	// Append operations that takeover a specific generation are idempotent.
+	isIdempotent = isIdempotent || w.Append && w.o.gen > 0
 	opts := makeStorageOpts(isIdempotent, w.o.retry, w.o.userProject)
 	params := &openWriterParams{
 		ctx:                  w.ctx,

Original file line number	Diff line number	Diff line change
`@@ -272,6 +272,8 @@ func (w *Writer) openWriter() (err error) {`
`272`	`272`	`}`
`273`	`273`
`274`	`274`	`isIdempotent := w.o.conds != nil && (w.o.conds.GenerationMatch >= 0 \|\| w.o.conds.DoesNotExist)`
	`275`	`+ // Append operations that takeover a specific generation are idempotent.`
	`276`	`+ isIdempotent = isIdempotent \|\| w.Append && w.o.gen > 0`
`275`	`277`	`opts := makeStorageOpts(isIdempotent, w.o.retry, w.o.userProject)`
`276`	`278`	`params := &openWriterParams{`
`277`	`279`	`ctx: w.ctx,`