On Tue, Jan 17, 2017 at 12:10:31PM -0800, Martin von Zweigbergk via Mercurial-devel wrote: > # HG changeset patch > # User Martin von Zweigbergk <martinv...@google.com> > # Date 1484681102 28800 > # Tue Jan 17 11:25:02 2017 -0800 > # Node ID 2fbfddbea687ad8627b26dc856694f70078eb2b4 > # Parent 7e933c9a4009d942b88bfbcb4e579a4b3f4dceca > revlog: give EXTSTORED flag value to narrowhg
I'm (obviously?) in favor of this patch series, especially this last one, but I won't pretend to be an impartial reviewer. It occurred to me while talking this over with Martin that ellipsis nodes might actually be able to overload the ISCENSORED flag - censor wants to look for special metadata, but perhaps narrow's "just trust me on the hash of this revision" behavior is similar enough to censor that we should try and consolidate down to a single flag for that purpose. Thoughts? I'm happy to talk at length about narrowhg implementation details if it'll help think this through. (Note that censor doesn't even pretend to work on anything other than filelogs, so you'd never (today) see censor outside a filelog. Ellipsis nodes, on the other hand, can exist in any revlog as currently implemented in narrowhg.) > > Narrowhg has been using "1 << 14" as its revlog flag value for a long > time. We (Google) have many repos with that value in production > already. When the same value was reserved for EXTSTORED, it made those > repos invalid. Upgrading them will be a little painful. We should > clearly have reserved the value for narrowhg a long time ago. Since > the EXTSTORED flag is not yet in any release and Facebook also says > they have not started using it in production, so it should be okay to > change it. This patch gives the current value (1 << 14) back to > narrowhg and gives a new value (1 << 13) to EXTSTORED. > > diff -r 7e933c9a4009 -r 2fbfddbea687 mercurial/help/internals/revlogs.txt > --- a/mercurial/help/internals/revlogs.txt Tue Jan 17 11:45:10 2017 -0800 > +++ b/mercurial/help/internals/revlogs.txt Tue Jan 17 11:25:02 2017 -0800 > @@ -94,7 +94,10 @@ > > 0: REVIDX_ISCENSORED revision has censor metadata, must be verified. > > - 1: REVIDX_EXTSTORED revision data is stored externally. > + 1: REVIDX_ELLIPSIS revision hash does not match its data. Used by > + narrowhg > + > + 2: REVIDX_EXTSTORED revision data is stored externally. > > 8-11 (4 bytes) > Compressed length of revision data / chunk as stored in revlog. > diff -r 7e933c9a4009 -r 2fbfddbea687 mercurial/revlog.py > --- a/mercurial/revlog.py Tue Jan 17 11:45:10 2017 -0800 > +++ b/mercurial/revlog.py Tue Jan 17 11:25:02 2017 -0800 > @@ -54,11 +54,13 @@ > > # revlog index flags > REVIDX_ISCENSORED = (1 << 15) # revision has censor metadata, must be > verified > -REVIDX_EXTSTORED = (1 << 14) # revision data is stored externally > +REVIDX_ELLIPSIS = (1 << 14) # revision hash does not match data (narrowhg) > +REVIDX_EXTSTORED = (1 << 13) # revision data is stored externally > REVIDX_DEFAULT_FLAGS = 0 > # stable order in which flags need to be processed and their processors > applied > REVIDX_FLAGS_ORDER = [ > REVIDX_ISCENSORED, > + REVIDX_ELLIPSIS, > REVIDX_EXTSTORED, > ] > REVIDX_KNOWN_FLAGS = util.bitsfrom(REVIDX_FLAGS_ORDER) > _______________________________________________ > Mercurial-devel mailing list > Mercurial-devel@mercurial-scm.org > https://www.mercurial-scm.org/mailman/listinfo/mercurial-devel _______________________________________________ Mercurial-devel mailing list Mercurial-devel@mercurial-scm.org https://www.mercurial-scm.org/mailman/listinfo/mercurial-devel
