error: add CensoredNodeError, will be thrown when content deliberately erased This change introduces the error plus a corresponding catch in dispatch, to provide localized error messages. The verb "censor" is used in this commit and all following to refer to erasing the content of a revlog revision (filelog, for now) without recalculating node IDs, leaving that revision invalid. Further work must be done to safely share such revision data with compliant clients. I find the analogy to censorship straightforward; for less politically charged options, consider "erase", "excise", "expunge", or "blackhole".

files: cache repo.dirstate For a large repo, 'hg files' goes from 2.27 seconds to 1.92.

files: only check for removed, not unknown or missing ctx.matches() doesn't return unknown files, and repo.dirstate[f] never returns '!' for an answer.

files: use ctx.matches instead of ctx.walk ctx.matches() is an optimized form of ctx.walk() when we don't care about the state of files on disk. For a large repo, 'hg files > /dev/null' drops from 3.7 seconds to 2.3.

files: actually filter out removed files 'hg files' makes an attempt to filter out removed files, but that doesn't work because repo.dirstate[f] returns lowercase 'r', not uppercase.

subrepo: remove superfluous newline from subrepo prompt

ui: show prompt choice if input is not a tty but is forced to be interactive The tests often set ui.interactive to control normally interactive prompts from stdin. That gave an output where it was non-obvious what prompts got which which response, and the output lacked the newline users would see after input. Instead, if the input not is a tty, write the selection and a newline.

merge with stable

help: basic support for showing only specified topic sections For instance, 'hg help config.files' will show only the Files section.

help: use OS containers for config file lists