A description of a set of changes to a file tree to be made as part of
a git commit, modeled as zero or more file additions and zero or more
file deletions.

Both fields are optional; omitting both will produce a commit with no
file changes.

deletions and additions describe changes to files identified
by their path in the git tree using unix-style path separators, i.e.
/. The root of a git tree is an empty string, so paths are not
slash-prefixed.

path values must be unique across all additions and deletions
provided. Any duplication will result in a validation error.

Encoding

File contents must be provided in full for each FileAddition.

The contents of a FileAddition must be encoded using RFC 4648
compliant base64, i.e. correct padding is required and no characters
outside the standard alphabet may be used. Invalid base64
encoding will be rejected with a validation error.

The encoded contents may be binary.

For text files, no assumptions are made about the character encoding of
the file contents (after base64 decoding). No charset transcoding or
line-ending normalization will be performed; it is the client's
responsibility to manage the character encoding of files they provide.
However, for maximum compatibility we recommend using UTF-8 encoding
and ensuring that all files in a repository use a consistent
line-ending convention (\n or \r\n), and that all files end
with a newline.

Modeling file changes

Each of the the five types of conceptual changes that can be made in a
git commit can be described using the FileChanges type as follows:

1. New file addition: create file hello world\n at path docs/README.txt:

   {
     "additions" [
       {
         "path": "docs/README.txt",
         "contents": base64encode("hello world\n")
       }
     ]
   }
   

2. Existing file modification: change existing docs/README.txt to have new
   content new content here\n:

   {
     "additions" [
       {
         "path": "docs/README.txt",
         "contents": base64encode("new content here\n")
       }
     ]
   }
   

3. Existing file deletion: remove existing file docs/README.txt.
   Note that the path is required to exist -- specifying a
   path that does not exist on the given branch will abort the
   commit and return an error.

   {
     "deletions" [
       {
         "path": "docs/README.txt"
       }
     ]
   }
   

4. File rename with no changes: rename docs/README.txt with
   previous content hello world\n to the same content at
   newdocs/README.txt:

   {
     "deletions" [
       {
         "path": "docs/README.txt",
       }
     ],
     "additions" [
       {
         "path": "newdocs/README.txt",
         "contents": base64encode("hello world\n")
       }
     ]
   }
   

5. File rename with changes: rename docs/README.txt with
   previous content hello world\n to a file at path
   newdocs/README.txt with content new contents\n:

   {
     "deletions" [
       {
         "path": "docs/README.txt",
       }
     ],
     "additions" [
       {
         "path": "newdocs/README.txt",
         "contents": base64encode("new contents\n")
       }
     ]
   }