# [GSoC] Git Blog 1 3 messages from 2021-05-23 to 2021-05-26. Participants: ZheNing Hu, Christian Couder. Thread: https://gitlist.dev/t/55763 ## ZheNing Hu, 2021-05-23 10:53 Subject: [GSoC] Git Blog 1 Message-ID: URL: https://gitlist.dev/e/CAOLTT8Tu1Xvc6sJ79n6f9B6TiuKp3akTQcQcuzEe7sG-kVOXAA%40mail.gmail.com ``` My first week blog finished: The web version is here: https://adlternative.github.io/GSOC-Git-Blog-1/ ----- ## 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 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 `%(content:raw)` in ref-filter 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)` for `ref-filter`. Unfortunately, this patch has a big problem: I ignored the breakage on the test. This led me to discover a bigger problem: If our references points to a blob or a tree, and these objects may be binary files, 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. 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()`. 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/) 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! -- ZheNing Hu ``` ## Christian Couder, 2021-05-24 20:47 Subject: Re: [GSoC] Git Blog 1 Message-ID: URL: https://gitlist.dev/e/CAP8UFD0sG9La8zpns%2B9Vzz1FA3XG%2BOF0%2BgRTDLU1s16aVY1-Yg%40mail.gmail.com In-Reply-To: ``` On Sun, May 23, 2021 at 12:53 PM ZheNing Hu 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. > ----- > > ## 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/ > 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. > 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. ``` ## ZheNing Hu, 2021-05-26 09:22 Subject: Re: [GSoC] Git Blog 1 Message-ID: URL: https://gitlist.dev/e/CAOLTT8R1j5m7XHHGrf9SoAEBR85yaT%2BtNJGzS%2BPg1pcSm0csdA%40mail.gmail.com In-Reply-To: ``` Christian Couder 于2021年5月25日周二 上午4:47写道： > > On Sun, May 23, 2021 at 12:53 PM ZheNing Hu 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. > > > ----- > > > > ## 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/ > > > 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/ > Thanks for these grammatical corrections. I will apply them to my blog (very easy) > > 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. > Yes it is. > > 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" > Good suggestion. > > 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. Thanks. -- ZheNing Hu ```