On Tue, Nov 01, 2016 at 08:50:23PM -0000, Philip Oakley wrote: > > From "git help update-index": > > > > --[no-]assume-unchanged > > When this flag is specified, the object names recorded for > > the paths are not updated. Instead, this option sets/unsets > > the "assume unchanged" bit for the paths. When the "assume > > unchanged" bit is on, the user promises not to change the > > file and allows Git to assume that the working tree file > > matches what is recorded in the index. If you want to change > > the working tree file, you need to unset the bit to tell Git. > > This is sometimes helpful when working with a big project on > > a filesystem that has very slow lstat(2) system call (e.g. > > cifs). > > > > Git will fail (gracefully) in case it needs to modify this > > file in the index e.g. when merging in a commit; thus, in > > case the assumed-untracked file is changed upstream, you will > > need to handle the situation manually. > > > > The whole section (including the ones above this quote) are often confused > between the promises of the user, and the alleged promises of Git. Even in > the quote above the "Instead" probably shouldn't be there. I think the "Instead" is "we are not doing the usual update-index thing of reading the new data from disk; instead, we are _just_ setting the bit". Perhaps that can be spelled out more clearly, but I think just dropping "Instead" is a step backwards. > Given the number of misrepresentations (on the web) of what the bit does, > and the ongoing misunderstandings of users it does feel like the man page > article could be refreshed to be more assertive about the users promise, and > Git's cautions. I dunno. I know this has long been a source of confusion, but I specifically dug in the docs to see what we had, and I thought what I quoted above was pretty clear. That has "only" been around for about 2 years, and is fighting against other mis-advice on the Internet, though. So I'm not sure if it is badly worded, or if people simply do not see it. -Peff