bufio: bclose flushes only, does not close the underlying (Hare flag::NONE)

lib/bufio/bufio.ww

@@ -46,8 +46,10 @@
 // singletons (vtable_r / vtable_w / vtable_rw); ww's vtable always
 // carries all three callbacks (a zero-length rbuf/wbuf degenerates the
 // matching callback in-cb). Defer-handle (MANAGED_* ownership bits)
-// also deferred — caller owns rbuf/wbuf/src; bclose flushes + forwards
-// close but frees nothing. Both graduate with io fold-2 (#5).
+// also deferred — caller owns rbuf/wbuf/src; bclose flushes only and
+// neither frees nor closes (close-propagation rides #5
+// MANAGED_HANDLE, ref/hare/bufio/stream.ha:194). Both graduate with io
+// fold-2 (#5).
 
 package bufio;
 
@@ -292,20 +294,15 @@ fn bwrite(s: io.stream, buf: []u8) (size | io.error) = {
 	return buf.len: size;
 };
 
-// bclose — flush pending wbuf, forward close to src via io.close.
-// Caller-owned buffers/src are not freed (drew defer-handle deferral).
+// bclose — flush pending wbuf only; the underlying src is NOT closed.
+// Hare's close_buffered closes src solely under flag::MANAGED_HANDLE
+// (ref/hare/bufio/stream.ha:194); init's default flag::NONE
+// (stream.ha:73) flushes and leaves src to its owner. Close-propagation
+// rides the io fold-2 MANAGED_HANDLE machinery (#5), per the ownership
+// header (bufio.ww:46-50) — caller owns src, bclose frees/closes nothing.
 fn bclose(s: io.stream) (void | io.error) = {
 	let b: *stream = s: *stream;
-	let fr: (void | io.error) = flush(b);
-	match (fr) {
-	case void => { };
-	case let e: io.error => return e;
-	};
-	let cr: (void | io.error) = io.close(b.src);
-	match (cr) {
-	case void => return void;
-	case let e: io.error => return e;
-	};
+	return flush(b);
 };
 
 // ---- scanner (read-ahead tokenizer over an io.stream src) ----------------

lib/bufio/bufiotest.ww

@@ -43,6 +43,27 @@ fn errsource() io.stream = {
 	return &errvt;
 };
 
+// ---- a close-recording source for the no-propagate test ---------------
+//
+// closevt forwards writes to closesink (so a flush is observable) and
+// records whether its closer fired in srcclosed.
+let srcclosed: bool = false;
+let closevt: io.vtable;
+let closesink: memio.stream;
+
+fn closewrite(s: io.stream, buf: []u8) (size | io.error) = {
+	return io.write(&closesink.vt, buf);
+};
+fn closeclose(s: io.stream) (void | io.error) = {
+	srcclosed = true;
+	return void;
+};
+fn closesource() io.stream = {
+	closevt.writer = (&closewrite): *io.writer;
+	closevt.closer = (&closeclose): *io.closer;
+	return &closevt;
+};
+
 // ---- scanbyte: drain four bytes through a 2-byte window ---------------
 
 @test fn scanbytecases() void = {
@@ -732,6 +753,47 @@ fn errsource() io.stream = {
 	assert(!(raw[1] != 81u8));
 };
 
+// ---- bclose flushes but does NOT close the underlying ----------------
+//
+// Hare's close_buffered closes src only under flag::MANAGED_HANDLE
+// (ref/hare/bufio/stream.ha:194); init's default flag::NONE flushes
+// only. The close-recording closesource lets us assert both: the
+// buffered byte reaches the sink (flush) AND the closer never fires.
+@test fn streamclosenopropagate() void = {
+	srcclosed = false;
+	let raw: [8]u8;
+	closesink = memio.fixed(raw[0:8]);
+	let src: io.stream = closesource();
+
+	let rb: [4]u8;
+	let wb: [4]u8;
+	let b: bufio.stream = bufio.init(src, rb[0:4], wb[0:4]);
+	let nilbs: [1]u8;
+	bufio.setflush(&b, nilbs[0:0]);	// suppress the default '\n' detector
+
+	let p: io.stream = &b.vt;
+	let h: [2]u8;
+	h[0] = 80u8; h[1] = 81u8;	// "PQ"
+	let r: (size | io.error) = io.write(p, h[0:2]);
+	match (r) {
+	case let n: size => { assert(!(n: i32 != 2)); };
+	case let e: io.error => abort();
+	};
+	assert(!(closesink.pos != 0));	// still buffered
+
+	let cr: (void | io.error) = io.close(p);
+	match (cr) {
+	case void => { };
+	case let e: io.error => abort();
+	};
+	// Flush happened: the 2 buffered bytes reached the sink.
+	assert(!(closesink.pos != 2));
+	assert(!(raw[0] != 80u8));
+	assert(!(raw[1] != 81u8));
+	// But the underlying was NOT closed (Hare flag::NONE default).
+	assert(!srcclosed);
+};
+
 // ---- setflush with a custom non-empty byte-set -----------------------
 
 @test fn streamsetflushcustom() void = {