paper: make all source lines have the same minimum height Empty source lines in paper and coal themes used to have smaller height than every other line (because of the way line numbers are shown and because they are using smaller font). This wasn't very noticeable before the follow lines functionality was added, but after that just using the follow-lines button to select a block of code with empty lines would demonstrate the fact that empty lines didn't have enough height - there were white "gaps" in the selection block. Since this problem occurs when lines don't have any content inside, let's create a pseudo-element (it's unselectable because of that) which still doesn't have any content, but fills up empty lines to 100% of their height because of display: inline-block. This is the most natural way to solve this annoyance that I've found so far. Hardcoding height isn't useful because we can have wrapped lines, in which case multiple lines of text need to fit into a single <span>. Setting min-height or line-height doesn't remove the gaps when viewed in Chromium.

hgweb: make followlines button absolutely positioned It used to have position: absolute only on annotate page, but it makes sense to have it everywhere, because the button shouldn't affect other elements at all. Especially since the button has a set height, which meant that for certain smaller fonts source lines were changing their height on hover. Note that the button doesn't set any of the usual properties that accompany absolute position (top, right, bottom or left). These properties would position the button without any account for source line padding. Instead, margins are used (the button already has all margins defined, they do the job).

hgweb: insert followlines buttons before any children, including text nodes This way the buttons come before any other content, including text nodes. Because highlight extension replaces every line of text with some <span> elements that have CSS classes for highlighting, the placement of followlines buttons used to depend on if that extension was enabled or not. Let's make the placement more consistent, it'll help the next patch in this series.

wireproto: only expose "debugwireargs" to version 1 transports I'm not even sure this command should be enabled for version 1 transports. It is just a reflection endpoint for argument data. We definitely don't need to support it in version 2. Differential Revision: https://phab.mercurial-scm.org/D3184

wireproto: only expose "hello" command to version 1 transports This command is only ever used for the handshake in the SSH protocol. We probably don't even need for it to be a proper command. Let's not carry it forward to version 2 because I don't see a use for it there. Differential Revision: https://phab.mercurial-scm.org/D3183

wireproto: port branchmap to wire protocol v2 Differential Revision: https://phab.mercurial-scm.org/D3182

wireproto: port listkeys commands to wire protocol v2 Differential Revision: https://phab.mercurial-scm.org/D3181

wireproto: port keep command to wire protocol v2 This is pretty straightforward. Differential Revision: https://phab.mercurial-scm.org/D3180

wireproto: port heads command to wire protocol v2 After much thought and consideration, wire protocol version 2's commands will be defined in different functions from the existing commands. This will make it easier to implement these commands because it won't require shoehorning things like response formatting and argument declaration into the same APIs. For example, wire protocol version 1 requires that commands declare a fixed and ordered list of argument names. It isn't really possible to insert new arguments or have optional arguments without breaking backwards compatibility. Wire protocol version 2, however, uses CBOR maps for passing arguments. So arguments a) can be optional b) can be added without BC c) can be strongly typed. This commit starts our trek towards reimplementing the wire protocol for version 2 with the heads command. It is pretty similar to the existing heads command. One added feature is it can be told to operate on only public phase changesets. This is useful for making discovery faster when a repo has tens of thousands of draft phase heads (such as Mozilla's "try" repository). The HTTPv2 server-side protocol has had its `getargs()` implementation updated to reflect that arguments are a map and not a list. Differential Revision: https://phab.mercurial-scm.org/D3179

largefiles: wrap heads command handler more directly extensions.wrapfunction() is a more robust method for wrapping a function, since it allows multiple wrappers. While we're here, wrap the function registered with the command instead of installing a new command handler. Differential Revision: https://phab.mercurial-scm.org/D3178