patchdescribe-doc:fix a obscure error description in the git log documentation

From: zen96285 <zen96285@gmail.com>

The git log documentation says "The default option is 'short'." This is wrong. After testing, the default value of '--decorate' is 'auto', not 'short'.

There is no difference between 'auto' and 'short' in terminal, but there is a significant difference in how they behave in the shell.The information generated by the 'short' can be saved in shell variables, while the 'auto' can't.

Signed-off-by: AndyAo Zen96285@gmail.com
---
    describe-doc:fix a obscure error description in the git log documenta…
    
    The git log documentation says "The default option is 'short'." This is
    wrong. After testing, the default value of '--decorate' is 'auto', not
    'short'.
    
    There is no difference between 'auto' and 'short' in terminal, but there
    is a significant difference in how they behave in the shell.The
    information generated by the 'short' can be saved in shell variables,
    while the 'auto' can't.
    
    Signed-off-by: AndyAo Zen96285@gmail.com

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1030%2FAndy-AO%2Ffix_a_obscure_error_description_in_the_git_log_documentation-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1030/Andy-AO/fix_a_obscure_error_description_in_the_git_log_documentation-v1
Pull-Request: https://github.com/git/git/pull/1030

 Documentation/git-log.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Hi Andy, welcome to Git mailing list!

On 31/05/21 13.00, Andy AO via GitGitGadget wrote:

Why are info generated with 'short' option (and not 'auto') can be assigned to a variable?

Looks OK to me, thanks.

On 2021-05-31 06:00:56+0000, Andy AO via GitGitGadget <gitgitgadget@gmail.com> wrote:

Please use your real name and wrap your commit message at 50 characters for subject line and 72 characters for body.

Let's the commit message aside.

The default option is documented correctly as short. Please check out builtin/log.c:decorate_callback and builtin/log.c:parse_decoration_style.

Below command print nothing in my machine:

	git log --decorate -1 >/tmp/default
	git log --decorate=short -1 >/tmp/short
	cmp /tmp/default /tmp/short

I'm curious about your config and/or command invocation. From the code, I can't guess which scenario that's different.

I think you meant:

	git log -1 >/tmp/no-decorate

In that case, please check your "log.decorate" config.

Đoàn Trần Công Danh  <congdanhqx@gmail.com> writes:

Very good suggestions.  Thanks for raising these issues.

You two are thinking about two "defaults", I think. If a --decorate option you give does not say which kind of decoration you want, by default, you see the short output. The above shows that.

If you do not give any --decorate option, the command behaves as if you gave --decorate=auto, which is what the patch author wanted to say, I think.

Yes, and this (with redirection to file), I think you do not get any decoration---that is what you get from --decorate=auto, i.e.

	git log --decorate=auto -1 >/tmp/auto-decorate

I think the default discussed in the paragraph the patch touches is "what happens if you do not say what kind, i.e. "--decorate" not "--decorate=<what kind>", so "the default is 'short'" is correct, but at the same time, "even if you do not say --decorate, you'll see short decoration when on a terminal" is worth mentioning somewhere.

On 2021-05-31 15:57:17+0900, Junio C Hamano <gitster@pobox.com> wrote:

I forgot that I have log.decorate configured to 'short'. *facepalm*

I think something like this should be nice.

----8<----

Hi Đoàn,

On 31/05/21 13.47, Đoàn Trần Công Danh wrote:

I think the case here was Andy forwarded this patch from someone, which happened to be also himself. Maybe that From: line above can be removed, unless that he forwarded from other people (in which From: line must be preserved).

On 2021-05-31 14:49:32+0700, Bagas Sanjaya <bagasdotme@gmail.com> wrote:

Andy is using GitGitGadget bridge. That bridge uses its own email address (gitgitgadget@gmail.com).

Thus, the identity in the RFC 822's header: "From" should be ignored, and we should use the "From: " line in body instead.

In principle, GitGitGadget will use the Author identity in the commit that was pushed into GitHub to generate such "From: " line. So, it's Andy's resposibility to configure correct core.name and core.email in Andy's machine, and create a commit with correct authorship. Otherwise, GitGitGadget will create above message.

Hope that help.

There're two different default options for log --decorate:
* Should `--decorate` be given without any arguments, it's default to
  `short`
* Should neither `--decorate` nor `--no-decorate` be given, it's default
  to the `log.decorate` or `auto`.

We documented the former, but not the latter.

Let's document them, too.

Reported-by: Andy AO <zen96285@gmail.com>
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
---

 I'm reluctant to send this out since I would like to see Andy get familiar
 with the list.  However, it's a while since the original patch.

 Documentation/git-log.txt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)