Re: [PATCH 0/2] describe and diff: implement --no-optional-locks

"Benjamin Woodruff via GitGitGadget" <gitgitgadget@gmail.com> writes:

That is a wrong reasoning that is completely opposite, though.

The commands at the Porcelain level, like "status" and "diff", refresh the index for the CORRECTNESS purposes.

The commands at the plumbing level, which are designed to be used in your own scripts, like "diff-files" and "diff-index", do not refresh the index for the performance purposes. If your own script wants to produce correct result, your script IS responsible for refreshing the index after its last modification to working tree files before it starts to use the plumbing commands to inspect which ones are modified and which ones are not. This is so that your script has more control over when the index is refreshed. It does not have to pay cost to run refresh for each Git command it invokes, if it knows that it does not make any modification between the two invocations; it can instead refresh just once and then run these two plumbing commands.

So, it would be absolute no-no to make the Porcelain commands like "describe" and "diff" not to refresh the index before they work by default. As an optional behaviour, it might be acceptable if there is no other reasonable solutions (like, using plumbing commands if the callers are not you typing but your scripts calling them).