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From: Johannes Schindelin <johannes.schindelin@gmx.de>
To: git@vger.kernel.org
Cc: "Junio C Hamano" <gitster@pobox.com>,
	"Thomas Rast" <tr@thomasrast.ch>,
	"Phil Haack" <haacked@gmail.com>, "Jeff King" <peff@peff.net>,
	"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
	"Stefan Beller" <sbeller@google.com>,
	"Jason Frey" <jfrey@redhat.com>,
	"Philip Oakley" <philipoakley@iee.org>
Subject: [PATCH 0/9] Assorted fixes for `git config` (including the "empty sections" bug)
Date: Thu, 29 Mar 2018 17:18:30 +0200 (DST)	[thread overview]
Message-ID: <cover.1522336130.git.johannes.schindelin@gmx.de> (raw)

This patch series started out as a single patch trying to figure out what it
takes to fix that annoying bug that has been reported several times over the
years, where `git config --unset` would leave empty sections behind, and `git
config --add` would not reuse them.

Little did I know that this would turn not only into a full patch to fix this
issue, but into a full-blown series of nine patches.

The first patch is somewhat of a "while at it" bug fix that I first thought
would be a lot more critical than it actually is: It really only affects config
files that start with a section followed immediately (i.e. without a newline)
by a one-letter boolean setting (i.e. without a `= <value>` part). So while it
is a real bug fix, I doubt anybody ever got bitten by it.

Nonetheless, I would be confortable with this patch going into v2.17.0, even at
this late stage. The final verdict is Junio's, of course.

The next swath of patches add some tests, and adjust one test about which I
already complained at length yesterday, so I will spare you the same ordeal
today. These fixes are pretty straight-forward, and I always try to keep my
added tests as concise as possible, so please tell me if you find a way to make
them smaller (without giving up readability and debuggability).

Finally, the interesting part, where I do two things, essentially (with
preparatory steps for each thing):

1. I add the ability for `git config --unset/--unset-all` to detect that it
   can remove a section that has just become empty (see below for some more
   discussion of what I consider "become empty"), and

2. I add the ability for `git config [--add] key value` to re-use empty
   sections.

Note that the --unset/--unset-all part is the hairy one, and I would love it if
people could concentrate on wrapping their heads around that function, and
obviously tell me how I can change it to make it more readable (or even point
out incorrect behavior).

Now, to the really important part: why does this patch series not conflict with
my very early statements that we cannot simply remove empty sections because we
may end up with stale comments?

Well, the patch in question takes pains to determine *iff* there are any
comments surrounding, or included in, the section. If any are found: previous
behavior. Under the assumption that the user edited the file, we keep it as
intact as possible (see below for some argument against this). If no comments
are found, and let's face it, this is probably *the* common case, as few people
edit their config files by hand these days (neither should they because it is
too easy to end up with an unparseable one), the now-empty section *is*
removed.

So what is the argument against this extra care to detect comments? Well, if
you have something like this:

	[section]
		; Here we comment about the variable called snarf
		snarf = froop

and we run `git config --unset section.snarf`, we end up with this config:

	[section]
		; Here we comment about the variable called snarf

which obviously does not make sense. However, that is already established
behavior for quite a few years, and I do not even try to think of a way how
this could be solved.


Johannes Schindelin (9):
  git_config_set: fix off-by-two
  t1300: rename it to reflect that `repo-config` was deprecated
  t1300: avoid relying on a bug
  t1300: remove unreasonable expectation from TODO
  t1300: `--unset-all` can leave an empty section behind (bug)
  git_config_set: simplify the way the section name is remembered
  git config --unset: remove empty sections (in normal situations)
  git_config_set: use do_config_from_file() directly
  git_config_set: reuse empty sections

 config.c                                    | 234 +++++++++++++++++++++++++---
 t/{t1300-repo-config.sh => t1300-config.sh} |  36 ++++-
 2 files changed, 250 insertions(+), 20 deletions(-)
 rename t/{t1300-repo-config.sh => t1300-config.sh} (98%)


base-commit: 03df4959472e7d4b5117bb72ac86e1e2bcf21723
Published-As: https://github.com/dscho/git/releases/tag/empty-config-section-v1
Fetch-It-Via: git fetch https://github.com/dscho/git empty-config-section-v1
-- 
2.16.2.windows.1.26.g2cc3565eb4b


             reply	other threads:[~2018-03-29 15:18 UTC|newest]

Thread overview: 103+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-29 15:18 Johannes Schindelin [this message]
2018-03-29 15:18 ` [PATCH 1/9] git_config_set: fix off-by-two Johannes Schindelin
2018-03-29 18:15   ` Stefan Beller
2018-03-29 19:41     ` Jeff King
2018-03-30 12:32       ` Johannes Schindelin
2018-03-30 14:15         ` Ævar Arnfjörð Bjarmason
2018-03-30 16:24           ` Junio C Hamano
2018-03-30 18:44             ` Johannes Schindelin
2018-03-30 19:00               ` Junio C Hamano
2018-04-03  9:31                 ` Johannes Schindelin
2018-04-03 15:29                   ` Duy Nguyen
2018-04-03 15:47                     ` Johannes Schindelin
2018-04-08 23:12                   ` Junio C Hamano
2018-03-30 16:36         ` Duy Nguyen
2018-03-30 18:53           ` Johannes Schindelin
2018-03-30 19:16             ` Duy Nguyen
2018-03-30 18:45         ` A potential approach to making tests faster on Windows Ævar Arnfjörð Bjarmason
2018-03-30 18:58           ` Junio C Hamano
2018-03-30 19:16           ` Jeff King
2018-04-03  9:49             ` Johannes Schindelin
2018-04-03 11:28               ` Ævar Arnfjörð Bjarmason
2018-04-03 15:55                 ` Johannes Schindelin
2018-04-03 21:36               ` Eric Sunshine
2018-04-03 11:43           ` Johannes Schindelin
2018-04-03 13:27             ` Jeff King
2018-04-03 16:00               ` Johannes Schindelin
2018-04-06 21:40                 ` Jeff King
2018-04-06 21:57                   ` Stefan Beller
2018-03-29 15:18 ` [PATCH 2/9] t1300: rename it to reflect that `repo-config` was deprecated Johannes Schindelin
2018-03-29 19:42   ` Jeff King
2018-03-30 12:37     ` Johannes Schindelin
2018-03-29 15:18 ` [PATCH 3/9] t1300: avoid relying on a bug Johannes Schindelin
2018-03-29 19:43   ` Jeff King
2018-03-30 12:38     ` Johannes Schindelin
2018-03-29 15:18 ` [PATCH 4/9] t1300: remove unreasonable expectation from TODO Johannes Schindelin
2018-03-29 19:52   ` Jeff King
2018-03-29 20:45     ` Junio C Hamano
2018-03-30 12:42     ` Johannes Schindelin
2018-03-29 15:18 ` [PATCH 5/9] t1300: `--unset-all` can leave an empty section behind (bug) Johannes Schindelin
2018-03-29 19:54   ` Jeff King
2018-03-29 15:18 ` [PATCH 6/9] git_config_set: simplify the way the section name is remembered Johannes Schindelin
2018-03-29 15:19 ` [PATCH 7/9] git config --unset: remove empty sections (in normal situations) Johannes Schindelin
2018-03-29 21:32   ` Jeff King
2018-03-30 13:00     ` Johannes Schindelin
2018-03-30 13:09       ` Jeff King
2018-03-29 15:19 ` [PATCH 8/9] git_config_set: use do_config_from_file() directly Johannes Schindelin
2018-03-29 21:38   ` Jeff King
2018-03-30 13:02     ` Johannes Schindelin
2018-03-30 13:14       ` Jeff King
2018-03-30 14:01         ` Johannes Schindelin
2018-03-30 14:08           ` Jeff King
2018-03-30 19:04             ` Johannes Schindelin
2018-03-29 15:19 ` [PATCH 9/9] git_config_set: reuse empty sections Johannes Schindelin
2018-03-29 21:50   ` Jeff King
2018-03-30 13:15     ` Johannes Schindelin
2018-03-29 17:58 ` [PATCH 0/9] Assorted fixes for `git config` (including the "empty sections" bug) Stefan Beller
2018-03-30 12:14   ` Johannes Schindelin
2018-03-29 19:39 ` Jeff King
2018-03-30 12:35   ` Johannes Schindelin
2018-03-30 14:17 ` Ævar Arnfjörð Bjarmason
2018-03-30 18:46   ` Johannes Schindelin
2018-04-03 16:27 ` [PATCH v2 00/15] " Johannes Schindelin
2018-04-03 16:28   ` [PATCH v2 01/15] git_config_set: fix off-by-two Johannes Schindelin
2018-04-03 16:28   ` [PATCH v2 02/15] t1300: rename it to reflect that `repo-config` was deprecated Johannes Schindelin
2018-04-03 16:28   ` [PATCH v2 03/15] t1300: demonstrate that --replace-all can "invent" newlines Johannes Schindelin
2018-04-03 16:28   ` [PATCH v2 04/15] config --replace-all: avoid extra line breaks Johannes Schindelin
2018-04-03 16:28   ` [PATCH v2 05/15] t1300: avoid relying on a bug Johannes Schindelin
2018-04-03 16:28   ` [PATCH v2 06/15] t1300: remove unreasonable expectation from TODO Johannes Schindelin
2018-04-03 16:28   ` [PATCH v2 07/15] t1300: `--unset-all` can leave an empty section behind (bug) Johannes Schindelin
2018-04-03 16:28   ` [PATCH v2 08/15] config: introduce an optional event stream while parsing Johannes Schindelin
2018-04-06 21:22     ` Jeff King
2018-04-09  7:35       ` Johannes Schindelin
2018-04-03 16:28   ` [PATCH v2 09/15] config: avoid using the global variable `store` Johannes Schindelin
2018-04-06 21:23     ` Jeff King
2018-04-09  7:36       ` Johannes Schindelin
2018-04-03 16:28   ` [PATCH v2 10/15] config_set_store: rename some fields for consistency Johannes Schindelin
2018-04-03 16:28   ` [PATCH v2 11/15] git_config_set: do not use a state machine Johannes Schindelin
2018-04-06 21:28     ` Jeff King
2018-04-09  7:50       ` Johannes Schindelin
2018-04-03 16:28   ` [PATCH v2 12/15] git_config_set: make use of the config parser's event stream Johannes Schindelin
2018-04-03 16:28   ` [PATCH v2 13/15] git config --unset: remove empty sections (in the common case) Johannes Schindelin
2018-04-03 16:29   ` [PATCH v2 14/15] git_config_set: reuse empty sections Johannes Schindelin
2018-04-03 16:30   ` [PATCH v2 00/15] Assorted fixes for `git config` (including the "empty sections" bug) Johannes Schindelin
2018-04-06 21:33   ` Jeff King
2018-04-09  8:19     ` Johannes Schindelin
2018-04-09  8:31   ` [PATCH v3 " Johannes Schindelin
2018-04-09  8:31     ` [PATCH v3 01/15] git_config_set: fix off-by-two Johannes Schindelin
2018-04-09  8:31     ` [PATCH v3 02/15] t1300: rename it to reflect that `repo-config` was deprecated Johannes Schindelin
2018-04-09  8:31     ` [PATCH v3 03/15] t1300: demonstrate that --replace-all can "invent" newlines Johannes Schindelin
2018-04-09  8:31     ` [PATCH v3 04/15] config --replace-all: avoid extra line breaks Johannes Schindelin
2018-04-09  8:31     ` [PATCH v3 05/15] t1300: avoid relying on a bug Johannes Schindelin
2018-04-09  8:31     ` [PATCH v3 06/15] t1300: remove unreasonable expectation from TODO Johannes Schindelin
2018-04-09  8:31     ` [PATCH v3 07/15] t1300: add a few more hairy examples of sections becoming empty Johannes Schindelin
2018-04-09  8:32     ` [PATCH v3 08/15] t1300: `--unset-all` can leave an empty section behind (bug) Johannes Schindelin
2018-04-09  8:32     ` [PATCH v3 09/15] config: introduce an optional event stream while parsing Johannes Schindelin
2018-04-09  8:32     ` [PATCH v3 10/15] config: avoid using the global variable `store` Johannes Schindelin
2018-04-09  8:32     ` [PATCH v3 11/15] config_set_store: rename some fields for consistency Johannes Schindelin
2018-04-09  8:32     ` [PATCH v3 12/15] git_config_set: do not use a state machine Johannes Schindelin
2018-04-09  8:32     ` [PATCH v3 13/15] git_config_set: make use of the config parser's event stream Johannes Schindelin
2018-05-08 13:42       ` Jeff King
2018-05-08 14:00         ` Jeff King
2018-04-09  8:32     ` [PATCH v3 14/15] git config --unset: remove empty sections (in the common case) Johannes Schindelin
2018-04-09  8:32     ` [PATCH v3 15/15] git_config_set: reuse empty sections Johannes Schindelin

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