namespaces: let namespaces override singlenode() definition Some namespaces have multiple nodes per name (meaning that their namemap() returns multiple nodes). One such namespace is the "topics" namespace (from the evolve repo). We also have our own internal namespace at Google (for review units) that has multiple nodes per name. These namespaces may not want to use the default "pick highest revnum" resolution that we currently use when resolving a name to a single node. As an example, they may decide that `hg co <name>` should check out a commit that's last in some sense even if an earlier commit had just been amended and thus had a higher revnum [1]. This patch gives the namespace the option to continue to return multiple nodes and to override how the best node is picked. Allowing namespaces to override that may also be useful as an optimization (it may be cheaper for the namespace to find just that node). I have been arguing (in D3715) for using all the nodes returned from namemap() when resolving the symbol to a revset, so e.g. `hg log -r stable` would resolve to *all* nodes on stable, not just the one with the highest revnum (except that I don't actually think we should change it for the branch namespace because of BC). Most people seem opposed to that. If we decide not to do it, I think we can deprecate the namemap() function in favor of the new singlenode() (I find it weird to have namespaces, like the branch namespace, where namemap() isn't nodemap()'s inverse). I therefore think this patch makes sense regardless of what we decide on that issue. [1] Actually, even the branch namespace would have wanted to override singlenode() if it had supported multiple nodes. That's because closes branch heads are mostly ignored, so "hg co default" will not check out the highest-revnum node if that's a closed head. Differential Revision: https://phab.mercurial-scm.org/D3852

rebase: refactor dryrun implementation This patch refactor dry-run code to make it easy to add additional functionality in dryrun. Otherwise we had to add every functionality through _origrebase() which does not seem a good implementation. Differential Revision: https://phab.mercurial-scm.org/D3849

hooks: allow Unix style environment variables on external Windows hooks This will help making common hooks between Windows and non-Windows platforms. Having to build the shellenviron dict here and in procutil.system() is a bit unfortunate, but the only other option is to fix up the command inside procutil.system(). It seems more important that the note about the hook being run reflects what is actually run. The patch from last summer added the hooks on the command line, but it looks like HG_ARGS has since learned about --config args, and the output was just confusing. Therefore, it's now loaded from a file in the histedit test for clarity.