I don't know of any, but the key thing to know is how to edit diffs manually. If you've ever run git add or reset with the -p parameter, you may have noticed an option where you can manually edit a diff hunk. If you choose that option, it describes several rules for editing hunks:
1. Remove lines beginning with + to keep them from being added
2. Replace the beginning - with <space> for lines to keep them from being removed
But you can go further with this by adding more lines beginning with + to add lines that weren't in the original hunk, or add a - prefix to a context line (beginning with a <space>) to remove it. You can even modify the content of lines prefixed with + (i.e., to fix a syntax error you noticed) before staging them.
The other thing to note is the surrounding context lines for a given hunk. Ideally, you have at least 3 lines before and 3 lines after the hunk to ensure that when it's applied, it changes the file in the correct location.
In order to actually stage a hunk, you need to add the necessary header lines above the line that begins with @@. These lines are the ones that begin with diff, index, ---, and +++. For the first, third and fourth lines, the path and file name need to match the file you intend to apply the patch to.
When you're ready to stage your edited hunk, you just visually highlight it in vim (shift-v) and then run
:'<,'> !git apply --cached --recount
The --cached option prevents git from trying to modify the file in the working tree and limits it to just modifying what's in the git index. The --recount option basially makes it easier to apply an edited patch by not really looking at the line that begins with @@. If your patch applies, you can view how it looks like in the index by running
git status -v
or
git diff --cached
You can even view the file as it is in the git index by running
1. Remove lines beginning with + to keep them from being added
2. Replace the beginning - with <space> for lines to keep them from being removed
But you can go further with this by adding more lines beginning with + to add lines that weren't in the original hunk, or add a - prefix to a context line (beginning with a <space>) to remove it. You can even modify the content of lines prefixed with + (i.e., to fix a syntax error you noticed) before staging them.
The other thing to note is the surrounding context lines for a given hunk. Ideally, you have at least 3 lines before and 3 lines after the hunk to ensure that when it's applied, it changes the file in the correct location.
In order to actually stage a hunk, you need to add the necessary header lines above the line that begins with @@. These lines are the ones that begin with diff, index, ---, and +++. For the first, third and fourth lines, the path and file name need to match the file you intend to apply the patch to.
When you're ready to stage your edited hunk, you just visually highlight it in vim (shift-v) and then run
The --cached option prevents git from trying to modify the file in the working tree and limits it to just modifying what's in the git index. The --recount option basially makes it easier to apply an edited patch by not really looking at the line that begins with @@. If your patch applies, you can view how it looks like in the index by running or You can even view the file as it is in the git index by running