From f6a1e1e288d13472f5f7fe2b907bb8c0bd69a018 Mon Sep 17 00:00:00 2001 From: Jim Hill Date: Sun, 17 May 2015 17:41:45 -0700 Subject: [PATCH] sha1_file: pass empty buffer to index empty file `git add` of an empty file with a filter pops complaints from `copy_fd` about a bad file descriptor. This traces back to these lines in sha1_file.c:index_core: if (!size) { ret = index_mem(sha1, NULL, size, type, path, flags); The problem here is that content to be added to the index can be supplied from an fd, or from a memory buffer, or from a pathname. This call is supplying a NULL buffer pointer and a zero size. Downstream logic takes the complete absence of a buffer to mean the data is to be found elsewhere -- for instance, these, from convert.c: if (params->src) { write_err = (write_in_full(child_process.in, params->src, params->size) < 0); } else { write_err = copy_fd(params->fd, child_process.in); } ~If there's a buffer, write from that, otherwise the data must be coming from an open fd.~ Perfectly reasonable logic in a routine that's going to write from either a buffer or an fd. So change `index_core` to supply an empty buffer when indexing an empty file. There's a patch out there that instead changes the logic quoted above to take a `-1` fd to mean "use the buffer", but it seems to me that the distinction between a missing buffer and an empty one carries intrinsic semantics, where the logic change is adapting the code to handle incorrect arguments. Signed-off-by: Jim Hill Signed-off-by: Junio C Hamano --- sha1_file.c | 2 +- t/t0021-conversion.sh | 26 ++++++++++++++++++++++++++ 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/sha1_file.c b/sha1_file.c index a38854ce55..6e2d6ec65b 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -3119,7 +3119,7 @@ static int index_core(unsigned char *sha1, int fd, size_t size, int ret; if (!size) { - ret = index_mem(sha1, NULL, size, type, path, flags); + ret = index_mem(sha1, "", size, type, path, flags); } else if (size <= SMALL_FILE_SIZE) { char *buf = xmalloc(size); if (size == read_in_full(fd, buf, size)) diff --git a/t/t0021-conversion.sh b/t/t0021-conversion.sh index b92e6cb046..b778faf1c8 100755 --- a/t/t0021-conversion.sh +++ b/t/t0021-conversion.sh @@ -204,4 +204,30 @@ test_expect_success EXPENSIVE 'filter large file' ' ! test -s err ' +test_expect_success "filter: clean empty file" ' + git config filter.in-repo-header.clean "echo cleaned && cat" && + git config filter.in-repo-header.smudge "sed 1d" && + + echo "empty-in-worktree filter=in-repo-header" >>.gitattributes && + >empty-in-worktree && + + echo cleaned >expected && + git add empty-in-worktree && + git show :empty-in-worktree >actual && + test_cmp expected actual +' + +test_expect_success "filter: smudge empty file" ' + git config filter.empty-in-repo.clean "cat >/dev/null" && + git config filter.empty-in-repo.smudge "echo smudged && cat" && + + echo "empty-in-repo filter=empty-in-repo" >>.gitattributes && + echo dead data walking >empty-in-repo && + git add empty-in-repo && + + echo smudged >expected && + git checkout-index --prefix=filtered- empty-in-repo && + test_cmp expected filtered-empty-in-repo +' + test_done