revlog: group delta computation methods under _deltacomputer object Extracting these methods from revlog will allow changing the implementation of the deltacomputer, by providing this interface: __init__(self, revlog) - constructor that initialize the object from a given revlog buildtext(self, revinfo, fh) - builds the fulltext version of a revision from a _revisioninfo object and the file handle to the .d (or .i for inline mode) file. finddeltainfo(self, revinfo, fh) - find a revision in the revlog against which it is acceptable to build a delta, and build the corresponding _deltainfo. It should now be easier to write an experimental feature that would replace _deltacomputer by another object, for example one that would know how to parallelize the delta computation in order to quicken the storage of multiple revisions.

revlog: refactor out _finddeltainfo from _addrevision Splicing the code into smaller chunks should help understanding it, and eventually override some parts in experimental branches to try optimization.

localrepo: micro-optimize __len__() to bypass repoview Since len(changelog) isn't overridden, we don't have to validate a cache of unfiltered changelog. $ python -m timeit -n 10000 \ -s 'from mercurial import hg, ui; repo = hg.repository(ui.ui());' \ 'len(repo)' orig) 10000 loops, best of 3: 32.1 usec per loop new) 10000 loops, best of 3: 1.79 usec per loop Spotted by Jordi Gutiérrez Hermoso.

lfs: defer registering the pre-push hook until blobs are committed The hook searches outgoing commits for blobs, and uploads them before letting the push occur. No reason to search for that which isn't there.

lfs: dump the full response on httperror in debug mode This was immensely helpful in diagnosing the 500: Internal Server Error when using workers to upload. It's a nasty wall of html, so we really can't do anything else with it.

lfs: default the User-Agent header for blob transfers to 'git-lfs' The custom User-Agent for blob transfers was added in e7bb5fc4570c. Now I've hit another incompatibility with a server wanting the string to start with 'git' or 'git-lfs' [1]. I don't feel strongly about this either way, but a Wireshark trace of git shows that when the Batch API is hit, the User-Agent is 'git-lfs/2.3.4'. So this would probably ensure maximum interoperability. This still leaves the experimental knob in, just in case. [1] https://bitbucket.org/sdorra/scm-manager/src/095a027178888bc2b819aebfae3d2c192c858030/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/web/GitUserAgentProvider.java?at=default&fileviewer=file-view-default#GitUserAgentProvider.java-117

lfs: default to not using workers for upload/download I ran into truncated uploads with this defaulting to on. Wojciech Lis diagnosed it as creating keepalive connections prior to forking, and illegally multiplexing the same connection. [1] I didn't notice a problem with the couple of downloads I tried, but disabled both for simplicity and safety. [1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2018-January/109916.html

lfs: add the '{lfsattrs}' template keyword to '{lfs_files}' This provides access to the metadata dictionary contained within the tracked pointer file. The OID is probably the most important attribute, and has its own keyword. But we might as well have this for completeness. I liked {pointer} better, but couldn't make it work with the singular/plural forms.

debugdownload: read repository hgrc if there is one The command does not require a repository, but will use it if there is one. This simplifies the reading of the remote destination when testing for largefile based url.

test-blackbox: stabilize for Windows This goes with 853bf7d90804.