[WIP-PATCH 0/2] send-email: refactor the email parser loop

While working on the new option `quote-email`, we needed to parse an email file. Since the work is already done, but the parsing and data processing are in the same loop, we wanted to refactor the parser, to make the code more maintainable.

This is still WIP, and one of the main issue (and we need your advice on that), is that around 30 tests will fail, and most of them are false-negatives: to pass, they rely on the format of what is displayed by `git send-email`, not only data.

For example, several tests will fail because they do a strict compare between `git send-email`'s output and:

   (mbox) Adding cc: A<author@example.com>  from line 'Cc: A<author@example.com>, One<one@example.com>'
   (mbox) Adding cc: One<one@example.com>  from line 'Cc: A<author@example.com>, One<one@example.com>'

Though `git send-email` now outputs something like:

   (mbox) Adding cc: A<author@example.com>  from line 'Cc: A<author@example.com>'
   (mbox) Adding cc: One<one@example.com>  from line 'Cc: One<one@example.com>'

The new behavior is explained because parsing and processing are not done in the same function, and processing cannot know the exact line the data came from.

We can think of several solutions:

   1. Modify the parser, to give the script the knowledge of the exact
      line the data came from.

   2. Hack the tests: modify the script using the parser to artificially
      recreate the supposedly parsed line.
      (e.g. with a list.join(', ')-like function)

   3. Modify the tests to replace exact cmp by greps.

IMHO, we should consider option 3, since the tests should rely on data rather than exact outputs. It also makes the tests more maintainable, in the sense that they will be more resilient to future output modifications.

What do you think?

   [WIP-PATCH 1/2] send-email: create email parser subroutine
   [WIP-PATCH 2/2] send-email: use refactored subroutine to parse patches

git-send-email.perl | 284 ++++++++++++++++++++++++++++++++++++++++++++--------------------------------
  1 file changed, 164 insertions(+), 120 deletions(-)