This simplifies pack file creation. A delta base could be read from a loose object, a packfile, or it might be available in a temporary file. All these cases can now be handled the same way. We may need to open, close, and re-open a given delta base multiple times while packing.

This way, the size of a raw object is the same regardless of whether the object was found in a loose object file or in a pack file.

This will be required by a future 'gotadmin pack' command.

This will be required by a future 'gotadmin pack' command.

ok tracey

On Linux, pipes returned from pipe(2) only work in one direction. This broke 'got clone' over ssh in the -portable version because got-fetch-pack assumes it can use its fetchfd for both reading and writing. I wrote a complicated diff to use two pipe(2) calls instead of one, but millert suggested a simpler solution: Use socketpair(2) instead of pipe(2). ok millert jrick tracey

This has been shown to prevent mis-merges in some cases. It's probably not a final solution. We should look at what Git's "recursive merge" is doing and implement something similar. Keep using Myers during update/unstage. The advantage of Myers is that it produces smaller conflict chunks, and there are no known cases of mis-merges which affect update/unstage.