Re: [GSoC] Git Blog 1

From: Christian Couder <christian.couder@gmail.com>
Date: May 24, 2021, 20:47 UTC
Message-ID: <CAP8UFD0sG9La8zpns+9Vzz1FA3XG+OF0+gRTDLU1s16aVY1-Yg@mail.gmail.com>
In-Reply-To: <CAOLTT8Tu1Xvc6sJ79n6f9B6TiuKp3akTQcQcuzEe7sG-kVOXAA@mail.gmail.com>

On Sun, May 23, 2021 at 12:53 PM ZheNing Hu <adlternative@gmail.com> wrote:

>
> My first week blog finished:
> The web version is here:
> https://adlternative.github.io/GSOC-Git-Blog-1/

Great!

See some comments below, but you don't need to update your blog post for each comment. Some are just remarks that might help you.

Show 6 quoted lines

> -----
>
> ## Week1: Git Adventure Begin
>
> Use Git to submit Git patches to the Git community.
> Does it sound magical? I fell very lucky to be selected

s/fell/feel/

Show 18 quoted lines

> by the Git community this year and start my Git Adventure
> in GSoC.
>
> I am no stranger to Git usage, and before the start of GSoC,
> I have learned some Git source code content, but I only saw
> the tip of the iceberg of Git source code, there are still many
> things that I need to explore.
>
> ### What happened this week
> - In [[GSoC] Hello
> Git](https://lore.kernel.org/git/CAOLTT8SHE-ok3D+oLNSWFi7KPU==VQnTMDmC4YxUyNBJKmBD8A@mail.gmail.com/),
> Christian and JiangXin interacted with me.
> - I checked Olga's patch at Christian's prompt and learned a way
> to make `cat-file --batch` use `ref-filter` logic: Use `format_ref_array_item()`
> in `batch_object_write()`, this is indeed a good entry point. But
> before implementing this function, we must make `ref-filter`
> support the function of printing the original data of the object
> (as `cat-file --batch` does). I decided to reuse the atom

In your blog post it looks like a space is missing after "object" as we see "object(as".

> `%(content:raw)` in ref-filter to implement this function.

The above could be understood as saying that `%(content:raw)` already exists, which is not really true. Maybe you could say something like "I decided to add the ":raw" option to the existing `%(content)` atom in ref-filter.c to implement this function."

> ### The difficulties I met
> In [[PATCH] [GSOC] ref-filter: add contents:raw
> atom](https://lore.kernel.org/git/pull.958.git.1621500593126.gitgitgadget@gmail.com/),
> I submitted a patch, which support atom `%(content:raw)`

s/support/supports/

or

s/support/adds support for/

> for `ref-filter`.
>
> Unfortunately, this patch has a big problem:
> I ignored the breakage on the test. This led me to

Maybe: s/the breakage on the test/a test breakage/

> discover a bigger problem:
>
> If our references points to a blob or a tree, and  these objects may
> be binary files,

The raw content of a tree indeed contains the binary contents of the hashes it references, while other objects like commit and tags contain hashes in the hexadecimal format.

> this means that we cannot use functions related
> to `strcmp()`,`strlen()` or `strbuf_addstr()`. The possible '\0' will
> cause the output to be truncated. We have to think of a way to make
> `ref-filter` can accept the output of these binary content.

The strbuf API has functions to deal with binary content.

Show 7 quoted lines

> So I searched for all the codes in `ref-filter.c` that buffer might be
> truncated by '\0' and use the appropriate method to replace them.
>
> Just like replacing `strcmp()` with `memcmp()`, We can use `strbuf_add()`
> instead of `strbuf_addstr()`,
> At the same time I also wrote the equivalent `*._quote_buf_with_size()`
> to replace `*._quote_buf()`.

Nice!

> I just submit it to the mailing list right now:
> [[GSOC][RFC] ref-filter: add contents:raw atom]
> (https://lore.kernel.org/git/pull.959.git.1621763612.gitgitgadget@gmail.com/)

By the way a better title for your patch might be "[GSOC][RFC] ref-filter: add ':raw' option to %(contents) atom"

> I don’t know if this is the right approach at the moment, let
> us slowly wait for the suggestions of mentors and reviewers... ;-)

Thanks, Christian.