git-svn: branch: avoid systematic prompt for cert/pass

Commands such as "git svn init/fetch/dcommit" do not prompt for client
certificate/password if they are stored in SVN config file.  Make
"git svn branch" consistent with the other commands, as SVN::Client is
capable of building its own authentication baton from information in the
SVN config directory.

Signed-off-by: Monard Vong <travelingsoul86@gmail.com>
Signed-off-by: Eric Wong <normalperson@yhbt.net>
git svn: info: correctly handle absolute path args

Calling "git svn info $(pwd)" would hit:
  "Reading from filehandle failed at ..."
errors due to improper prefixing and canonicalization.

Strip the toplevel path from absolute filesystem paths to ensure
downstream canonicalization routines are only exposed to paths
tracked in git (or SVN).

v2:
  Thanks to Andrej Manduch for originally noticing the issue
  and fixing my original version of this to handle
  more corner cases such as "/path/to/top/../top" and
  "/path/to/top/../top/file" as shown in the new test cases.

v3:
  Fix pathname portability problems pointed out by Johannes Sixt
  with a hint from brian m. carlson.

Cc: Johannes Sixt <j6t@kdbg.org>
Cc: "brian m. carlson" <sandals@crustytoothpaste.net>
Signed-off-by: Andrej Manduch <amanduch@gmail.com>
Signed-off-by: Eric Wong <normalperson@yhbt.net>
git-svn.txt: Remove mentions of repack options

Git no longer seems to use these flags or their associated config keys;
when they are present, git-svn outputs a message indicating that they
are being ignored.

Signed-off-by: Lawrence Velázquez <vq@larryv.me>
Signed-off-by: Eric Wong <normalperson@yhbt.net>
git svn: find-rev allows short switches for near matches

Allow -B and -A to act as short aliases for --before and --after
options respectively.  This reduces typing and hopefully allows
reuse of muscle memory for grep(1) users.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
git-svn: delay term initialization

On my Debian 7 system, this fixes annoying warnings when the output
of "git svn" commands are redirected:

    Unable to get Terminal Size. The TIOCGWINSZ ioctl didn't work.
    The COLUMNS and LINES environment variables didn't work. The
    resize program didn't work.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
commit: provide a function to find a header in a buffer

Usually when we parse a commit, we read it line by line and
handle each individual line (e.g., parse_commit and
parse_commit_header).  Sometimes, however, we only care
about extracting a single header. Code in this situation is
stuck doing an ad-hoc parse of the commit buffer.

Let's provide a reusable function to locate a header within
the commit.  The code is modeled after pretty.c's
get_header, which is used to extract the encoding.

Since some callers may not have the "struct commit" to go
along with the buffer, we drop that parameter.  The only
thing lost is a warning for truncated commits, but that's
OK.  This shouldn't happen in practice, and even if it does,
there's no particular reason that this function needs to
complain about it. It either finds the header it was asked
for, or it doesn't (and in the latter case, the caller will
typically complain).
record_author_info: fix memory leak on malformed commit

If we hit the end-of-header without finding an "author"
line, we just return from the function. We should jump to
the fail_exit path to clean up the buffer that we may have
allocated.
record_author_info: use find_commit_header

This saves us some manual parsing and makes the code more
readable.
use strbufs in date functions

Many of the date functions write into fixed-size buffers.
This is a minor pain, as we have to take special
precautions, and frequently end up copying the result into a
strbuf or heap-allocated buffer anyway (for which we
sometimes use strcpy!).

Let's instead teach parse_date, datestamp, etc to write to a
strbuf. The obvious downside is that we might need to
perform a heap allocation where we otherwise would not need
to. However, it turns out that the only two new allocations
required are:

  1. In test-date.c, where we don't care about efficiency.

  2. In determine_author_info, which is not performance
     critical (and where the use of a strbuf will help later
     refactoring).
determine_author_info: reuse parsing functions

Rather than parsing the header manually to find the "author"
field, and then parsing its sub-parts, let's use
find_commit_header and split_ident_line. This is shorter and
easier to read, and should do a more careful parsing job.

For example, the current parser could find the end-of-email
right-bracket across a newline (for a malformed commit), and
calculate a bogus gigantic length for the date (by using
"eol - rb").

As a bonus, this also plugs a memory leak when we pull the
date field from an existing commit (we still leak the name
and email buffers, which will be fixed in a later commit).
determine_author_info: copy getenv output

When figuring out the author name for a commit, we may end
up either pointing to const storage from getenv("GIT_AUTHOR_*"),
or to newly allocated storage based on an existing commit or
the --author option.

Using const pointers to getenv's return has two problems:

  1. It is not guaranteed that the return value from getenv
     remains valid across multiple calls.

  2. We do not know whether to free the values at the end,
     so we just leak them.

We can solve both by duplicating the string returned by
getenv().