End a request quietly when the client has gone

A write that failed with EPIPE on an uncached page died into an error
page, which died again at exit when the page could not be sent either,
and git logged a recursion warning on every dropped connection. A
filter that exits early fails a write the same way, so the quiet exit
is kept for writes that reach the client itself.

1 file changed, 16 insertions, 0 deletions

diff --git a/tests/t0303-robustness.sh b/tests/t0303-robustness.sh
index 55a83c3..fd1c02e 100755
--- a/tests/t0303-robustness.sh
+++ b/tests/t0303-robustness.sh
@@ -529,6 +529,22 @@ test_expect_success 'the dumb transport withholds the alternates file' '
 	grep "^Status: 200" tmp
 '
 
+# A client that goes away mid-page leaves nobody to send an error page to,
+# so the request ends quietly instead of dying twice into the log. The page
+# has to outgrow the pipe for the write after the reader has gone to fail.
+test_expect_success 'a client that disconnects ends the request quietly' '
+	(
+		cd repos/rob &&
+		awk "BEGIN{for(i=0;i<20000;i++) print \"line \" i}" >long.txt &&
+		git add long.txt &&
+		git commit -m long
+	) &&
+	{ robq "url=rob/tree/long.txt" 2>err; echo $? >status; } | head -c 1 >/dev/null &&
+	test "$(cat status)" = 0 &&
+	! grep -i "broken pipe" err &&
+	! grep "die()" err
+'
+
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