drop vcs-svn experiment

The code in vcs-svn was started in 2010 as an attempt to build a
remote-helper for interacting with svn repositories (as opposed to
git-svn). However, we never got as far as shipping a mature remote
helper, and the last substantive commit was e99d012a6bc in 2012.

We do have a git-remote-testsvn, and it is even installed as part of
"make install". But given the name, it seems unlikely to be used by
anybody (you'd have to explicitly "git clone testsvn::$url", and there
have been zero mentions of that on the mailing list since 2013, and even
that includes the phrase "you might need to hack a bit to get it working
properly"[1]).

We also ship contrib/svn-fe, which builds on the vcs-svn work. However,
it does not seem to build out of the box for me, as the link step misses
some required libraries for using libgit.a. Curiously, the original
build breakage bisects for me to eff80a9fd9 (Allow custom "comment
char", 2013-01-16), which seems unrelated. There was an attempt to fix
it in da011cb0e7 (contrib/svn-fe: fix Makefile, 2014-08-28), but on my
system that only switches the error message.

So it seems like the result is not really usable by anybody in practice.
It would be wonderful if somebody wanted to pick up the topic again, and
potentially it's worth carrying around for that reason. But the flip
side is that people doing tree-wide operations have to deal with this
code.  And you can see the list with (replace "HEAD" with this commit as
appropriate):

  {
    echo "--"
    git diff-tree --diff-filter=D -r --name-only HEAD^ HEAD
  } |
  git log --no-merges --oneline e99d012a6bc.. --stdin

which shows 58 times somebody had to deal with the code, generally due
to a compile or test failure, or a tree-wide style fix or API change.
Let's drop it and let anybody who wants to pick it up do so by
resurrecting it from the git history.

As a bonus, this also reduces the size of a stripped installation of Git
from 21MB to 19MB.

[1] https://lore.kernel.org/git/CALkWK0mPHzKfzFKKpZkfAus3YVC9NFYDbFnt+5JQYVKipk3bQQ@mail.gmail.com/

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 0 insertions, 77 deletions

diff --git a/vcs-svn/line_buffer.txt b/vcs-svn/line_buffer.txt
deleted file mode 100644
index 8e139eb..0000000
--- a/vcs-svn/line_buffer.txt
+++ /dev/null
@@ -1,77 +0,0 @@
-line_buffer API
-===============
-
-The line_buffer library provides a convenient interface for
-mostly-line-oriented input.
-
-Each line is not permitted to exceed 10000 bytes.  The provided
-functions are not thread-safe or async-signal-safe, and like
-`fgets()`, they generally do not function correctly if interrupted
-by a signal without SA_RESTART set.
-
-Calling sequence
-----------------
-
-The calling program:
-
- - initializes a `struct line_buffer` to LINE_BUFFER_INIT
- - specifies a file to read with `buffer_init`
- - processes input with `buffer_read_line`, `buffer_skip_bytes`,
-   and `buffer_copy_bytes`
- - closes the file with `buffer_deinit`, perhaps to start over and
-   read another file.
-
-When finished, the caller can use `buffer_reset` to deallocate
-resources.
-
-Using temporary files
----------------------
-
-Temporary files provide a place to store data that should not outlive
-the calling program.  A program
-
- - initializes a `struct line_buffer` to LINE_BUFFER_INIT
- - requests a temporary file with `buffer_tmpfile_init`
- - acquires an output handle by calling `buffer_tmpfile_rewind`
- - uses standard I/O functions like `fprintf` and `fwrite` to fill
-   the temporary file
- - declares writing is over with `buffer_tmpfile_prepare_to_read`
- - can re-read what was written with `buffer_read_line`,
-   `buffer_copy_bytes`, and so on
- - can reuse the temporary file by calling `buffer_tmpfile_rewind`
-   again
- - removes the temporary file with `buffer_deinit`, perhaps to
-   reuse the line_buffer for some other file.
-
-When finished, the calling program can use `buffer_reset` to deallocate
-resources.
-
-Functions
----------
-
-`buffer_init`, `buffer_fdinit`::
-	Open the named file or file descriptor for input.
-	buffer_init(buf, NULL) prepares to read from stdin.
-	On failure, returns -1 (with errno indicating the nature
-	of the failure).
-
-`buffer_deinit`::
-	Stop reading from the current file (closing it unless
-	it was stdin).  Returns nonzero if `fclose` fails or
-	the error indicator was set.
-
-`buffer_read_line`::
-	Read a line and strip off the trailing newline.
-	On failure or end of file, returns NULL.
-
-`buffer_copy_bytes`::
-	Read `len` bytes of input and dump them to the standard output
-	stream.  Returns early for error or end of file.
-
-`buffer_skip_bytes`::
-	Discards `len` bytes from the input stream (stopping early
-	if necessary because of an error or eof).  Return value is
-	the number of bytes successfully read.
-
-`buffer_reset`::
-	Deallocates non-static buffers.