Re: [PATCH v1 9/9] diff --color-moved-ws: handle blank lines

From: Phillip Wood <phillip.wood@talktalk.net>
To: Stefan Beller <sbeller@google.com>,
	Phillip Wood <phillip.wood@dunelm.org.uk>
Cc: git <git@vger.kernel.org>
Subject: Re: [PATCH v1 9/9] diff --color-moved-ws: handle blank lines
Date: Wed, 21 Nov 2018 15:49:56 +0000	[thread overview]
Message-ID: <ef49bb0e-cf03-a707-f562-595564bd70d8@talktalk.net> (raw)
In-Reply-To: <CAGZ79kYm-uNWi-3=0fG=PfA3HbT7tKwER=r8fm6UFiy3P=JEmA@mail.gmail.com>

On 20/11/2018 18:05, Stefan Beller wrote:
> On Fri, Nov 16, 2018 at 3:04 AM Phillip Wood <phillip.wood@talktalk.net> wrote:
>>
>> From: Phillip Wood <phillip.wood@dunelm.org.uk>
>>
>> When using --color-moved-ws=allow-indentation-change allow lines with
>> the same indentation change to be grouped across blank lines. For now
>> this only works if the blank lines have been moved as well, not for
>> blocks that have just had their indentation changed.
>>
>> This completes the changes to the implementation of
>> --color-moved=allow-indentation-change. Running
>>
>>    git diff --color-moved=allow-indentation-change v2.18.0 v2.19.0
>>
>> now takes 5.0s. This is a saving of 41% from 8.5s for the optimized
>> version of the previous implementation and 66% from the original which
>> took 14.6s.
>>
>> Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
>> ---
>>
>> Notes:
>>      Changes since rfc:
>>       - Split these changes into a separate commit.
>>       - Detect blank lines when processing the indentation rather than
>>         parsing each line twice.
>>       - Tweaked the test to make it harder as suggested by Stefan.
>>       - Added timing data to the commit message.
>>
>>   diff.c                     | 34 ++++++++++++++++++++++++++++---
>>   t/t4015-diff-whitespace.sh | 41 ++++++++++++++++++++++++++++++++++----
>>   2 files changed, 68 insertions(+), 7 deletions(-)
>>
>> diff --git a/diff.c b/diff.c
>> index 89559293e7..072b5bced6 100644
>> --- a/diff.c
>> +++ b/diff.c
>> @@ -792,9 +792,11 @@ static void moved_block_clear(struct moved_block *b)
>>          memset(b, 0, sizeof(*b));
>>   }
>>
>> +#define INDENT_BLANKLINE INT_MIN
> 
> Answering my question from the previous patch:
> This is why we need to keep the indents signed.
> 
> This patch looks quite nice to read along.
> 
> The whole series looks good to me.

Thanks

> Do we need to update the docs in any way?

I'm not sure, at the moment it does not make any promises about the 
exact behavior of --color-moved-ws=allow-indentation-change, we could 
change it to be more explicit but I'm not sure it's worth it.

Thanks for looking over these patches, I'll post a reroll soon based on 
your comments.

Phillip

> Thanks,
> Stefan
> 