From: Jonathan Nieder Date: Mon, 13 Dec 2010 06:31:51 GMT Subject: [PATCH jn/fast-import-blob-access] t9300: avoid short reads from dd Message-ID: <20101213063151.GB20812@burratino> In-Reply-To: <2F4185D2-5846-45CB-BC92-6BC07AE5CEC8@gernhardtsoftware.com> dd is a thin wrapper around read(2). As open group Issue 7 explains: It shall read the input one block at a time, using the specified input block size; it shall then process the block of data actually returned, which could be smaller than the requested block size. Any short read --- for example from a pipe whose capacity cannot fill a block --- results in that block being truncated. As a result, the first cat-blob test (9300.114) fails on Mac OS X, where the pipe capacity is around 8 KiB. Fix the test by using a block size of 1. Each read will block until the next byte of input is available. It would be even nicer to use head -c which expresses the intention more clearly. Alas, IRIX "head" does not support the -c option. Reported-by: Brian Gernhardt Signed-off-by: Jonathan Nieder --- t/t9300-fast-import.sh | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh index 055ddc6..ed28d3c 100755 --- a/t/t9300-fast-import.sh +++ b/t/t9300-fast-import.sh @@ -1794,7 +1794,7 @@ test_expect_success PIPE 'R: copy using cat-file' ' read blob_id type size <&3 && echo "$blob_id $type $size" >response && - dd of=blob bs=$size count=1 <&3 && + dd of=blob bs=1 count=$size <&3 && read newline <&3 && cat <