Git Filter Delay Capability and Merge Attributes

the filter supports the "delay" capability then it must support the "list_available_blobs" command. If Git sends this command, then the filter is expected to return a list of pathnames representing blobs that have been delayed earlier and are now available. The list must be terminated with a flush packet followed by a "success" status that is also terminated with a flush packet. If no blobs for the delayed paths are available, yet, then the filter is expected to block the response until at least one blob becomes available. The filter can tell Git that it has no more delayed blobs by sending an empty list. As soon as the filter responds with an empty list, Git stops asking. All blobs that Git has not received at this point are considered missing and will result in an error. ------------------------ packet: git> command=list_available_blobs packet: git> 0000 packet: git< pathname=path/testfile.dat packet: git< pathname=path/otherfile.dat packet: git< 0000 packet: git< status=success packet: git< 0000 ------------------------ After Git received the pathnames, it will request the corresponding blobs again. These requests contain a pathname and an empty content section. The filter is expected to respond with the smudged content in the usual way as explained above. ------------------------ packet: git> command=smudge packet: git> pathname=path/testfile.dat packet: git> 0000 packet: git> 0000 # empty content! packet: git< status=success packet: git< 0000 packet: git< SMUDGED_CONTENT packet: git< 0000 packet: git< 0000 # empty list, keep "status=success" unchanged! ------------------------ Example ^^^^^^^ A long running filter demo implementation can be found in `contrib/long-running-filter/example.pl` located in the Git core repository. If you develop your own long running filter process then the `GIT_TRACE_PACKET` environment variables can be very helpful for debugging (see linkgit:git[1]). Please note that you cannot use an existing `filter.<driver>.clean` or `filter.<driver>.smudge` command with `filter.<driver>.process` because the former two use a different inter process communication protocol than the latter one. Interaction between checkin/checkout attributes ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ In the check-in codepath, the worktree file is first converted with `filter` driver (if specified and corresponding driver defined), then the result is processed with `ident` (if specified), and then finally with `text` (again, if specified and applicable). In the check-out codepath, the blob content is first converted with `text`, and then `ident` and fed to `filter`. Merging branches with differing checkin/checkout attributes ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ If you have added attributes to a file that cause the canonical repository format for that file to change, such as adding a clean/smudge filter or text/eol/ident attributes, merging anything where the attribute is not in place would normally cause merge conflicts. To prevent these unnecessary merge conflicts, Git can be told to run a virtual check-out and check-in of all three stages of each file that needs a three-way content merge, by setting the `merge.renormalize` configuration variable. This prevents changes caused by check-in conversion from causing spurious merge conflicts when a converted file is merged with an unconverted file. As long as a "smudge->clean" results in the same output as a "clean" even on files that are already smudged, this strategy will automatically resolve all filter-related conflicts. Filters that do not act in this way may cause additional merge conflicts that must be resolved manually. Generating diff text ~~~~~~~~~~~~~~~~~~~~ `diff` ^^^^^^ The attribute `diff` affects how Git generates diffs for particular files. It can tell Git whether to generate

The Git filter protocol supports delayed filtering and listing available blobs, and Git handles interactions between checkin/checkout attributes, including text, ident, and filter conversions, and provides a way to resolve merge conflicts caused by attribute differences using the 'merge.renormalize' configuration variable.