[PATCH v3 0/2] Add hostname condition to includeIf

Extend includeIf to take hostname into account. Motivating request can be found here [1].

[1] https://github.com/gitgitgadget/git/issues/1665

A lot of feedback was given to the v2 of this patch.

It was pointed out that it wasn't particularly obvious what it was meant by 

  "If the current hostname matches the pattern, the include condition is met."

which is definitely true. Despite this, to my knowledge, there isn't a way to precisely define what we mean by "hostname" other than saying that we mean whatever is returned by gethostname(2).

In my opinion, terms like "short hostname" can be confusing in some cases, and I'm not even sure we can rely on $hostname to agree with gethostname(2) in every platform.

I still think the documentation isn't great, but I don't see a way to improve it further.

Thanks everyone for the feedback!

Changes since v2:
* Expose the result of xgethostname through test-tool
* Rewrite test to rely on test-tool xgethostname rather than using
  $hostname
* Clarify documentation, specifying that by "hostname" we mean output of
  gethostname(2)

Changes since v1:
* Add blank line between declarations and code in `include_by_branch`.
* Rewrite "echo"s used in tests to make them more readable. 

Ignacio Encinas (2):
  t: add a test helper for getting hostname
  config: learn the "hostname:" includeIf condition

 Documentation/config.txt     | 10 +++++++++
 Makefile                     |  1 +
 config.c                     | 17 +++++++++++++++
 t/helper/test-tool.c         |  1 +
 t/helper/test-tool.h         |  1 +
 t/helper/test-xgethostname.c | 12 +++++++++++
 t/t1305-config-include.sh    | 42 ++++++++++++++++++++++++++++++++++++
 t/t6500-gc.sh                |  3 +--
 8 files changed, 85 insertions(+), 2 deletions(-)
 create mode 100644 t/helper/test-xgethostname.c

Range-diff against v2:
-:  ------------ > 1:  ee1f9b1da037 t: add a test helper for getting hostname
1:  cf175154109e ! 2:  dec622c38916 config: learn the "hostname:" includeIf condition
    @@ Documentation/config.txt: As for the naming of this keyword, it is for forwards
     +`hostname`::
     +	The data that follows the keyword `hostname:` is taken to be a
     +	pattern with standard globbing wildcards. If the current
    -+	hostname matches the pattern, the include condition is met.
    ++	hostname (output of gethostname(2)) matches the
    ++	pattern, the include condition is met.
     +
      A few more notes on matching via `gitdir` and `gitdir/i`:
      
    @@ t/t1305-config-include.sh: test_expect_success 'include cycles are detected' '
      
     +test_expect_success 'conditional include, hostname' '
     +	cat >>.git/config <<-EOF &&
    -+	[includeIf "hostname:$(hostname)a"]
    ++	[includeIf "hostname:$(test-tool xgethostname)a"]
     +		path = bar12
     +	EOF
     +	cat >>.git/bar12 <<-EOF &&
    @@ t/t1305-config-include.sh: test_expect_success 'include cycles are detected' '
     +	test_must_fail git config test.twelve &&
     +
     +	cat >>.git/config <<-EOF &&
    -+	[includeIf "hostname:$(hostname)"]
    ++	[includeIf "hostname:$(test-tool xgethostname)"]
     +		path = bar12
     +	EOF
     +	echo 12 >expect &&
    @@ t/t1305-config-include.sh: test_expect_success 'include cycles are detected' '
     +
     +test_expect_success 'conditional include, hostname, wildcard' '
     +	cat >>.git/config <<-EOF &&
    -+	[includeIf "hostname:$(hostname)a*"]
    ++	[includeIf "hostname:$(test-tool xgethostname)a*"]
     +		path = bar13
     +	EOF
     +	cat >>.git/bar13 <<-EOF &&
    @@ t/t1305-config-include.sh: test_expect_success 'include cycles are detected' '
     +	test_must_fail git config test.thirteen &&
     +
     +	cat >>.git/config <<-EOF &&
    -+	[includeIf "hostname:$(hostname)*"]
    ++	[includeIf "hostname:$(test-tool xgethostname)*"]
     +		path = bar13
     +	EOF
     +	echo 13 >expect &&

base-commit: e09f1254c54329773904fe25d7c545a1fb4fa920