largefiles: when setting/clearing x bit on largefiles, don't change other bits It is only the X bit that it matters to copy from the standin to the largefile in the working directory. While it generally doesn't do any harm to copy the whole mode, it is also "wrong" to copy more than the X bit we care about. It can make a difference if someone should try to handle largefiles differently, such as marking them read-only. Thus, do similar to what utils.setflags does and set the X bit where there are R bits and obey umask.

eol: on update, only re-check files if filtering changed Before, update would mark all files as 'normallookup' in dirstate if .hgeol changed so all files would get the new filtering applied. That takes some time ... and is pointless if the filtering for that file didn't change. Instead, keep track of the old filtering and only check files where the filtering is changed. To keep the old filtering, change to write the applied .hgeol content to .hg/eol.cache instead of just touching it. That change is backwards/forwards compatible. In a real world test, this takes an update that is changing .hgeol and 30000 files from 12s to 4s - where the remaining eol overhead is 1-2s.

dirs: add comment about _PyBytes_Resize So readers have a canonical function to compare this code to.

checkcopies: extract the '_related' closure There is not need for it to be a closure.

checkcopies: add an inline comment about the '_related' call This helps understanding the flow of the function.

checkcopies: minor change to comment This helped me understand the refactoring so this must be helpful.