color: stop mutating the default effects map A future change will make color.setup() callable a second time when the pager is spawned, in order to honor the 'color.pagermode' setting. The problem was that when 'color.mode=auto' was resolved to 'win32' in the first pass, the default ANSI effects were overwritten, making it impossible to honor 'pagermode=ansi'. Also, the two separate maps didn't have the same keys. The symmetric difference is 'dim' and 'italic' (from ANSI), and 'bold_background' (from win32). Thus, the update left entries that didn't belong for the current mode. This bled through `hg debugcolor`, where the unsupported ANSI keys were listed in 'win32' mode. As an added bonus, this now correctly enables color with MSYS `less` for a command like this, where pager is forced on: $ hg log --config color.pagermode=ansi --pager=yes --color=auto Previously, the output was corrupted. The raw output, as seen through the ANSI blind `more.com` was: <-[-1;6mchangeset: 34840:3580d1197af9<-[-1m ... which MSYS `less -FRX` rendered as: 1;6mchangeset: 34840:3580d1197af91m ... (The two '<-' instances were actually an arrow character that TortoiseHg warned couldn't be encoded, and notepad++ translated to a single '?'.) Returning an empty map for 'ui._colormode == None' seems better that defaulting to '_effects' (since some keys are mode dependent), and is better than None, which blows up `hg debugcolor --color=never`.

pager: do not read from environment variable $PAGER is converted to the pager.pager config item. So it's no longer necessary to read $PAGER in ui.pager().

ui: simplify geteditor Now $EDITOR and $VISUAL will affect ui.editor directly. So it's no longer necessary to test them in ui.geteditor.

debugconfig: list environment variables in debug output Since we print "read config from" for config files, printing environment variables will make it more consistent.

rcutil: let environ override system configs (BC) This is BC because system configs won't be able to override $EDITOR, $PAGER. The new behavior is arguably more rational.

rcutil: add a method to convert environment variables to config items Handling config and environ priorities has been messy. Partially because we don't have config layers - you either get all configs (sys + user), or none. Ideally, environ like $EDITOR, $PAGER should be able to override the system configs "ui.editor", "pager.pager". This patch provides the ability to convert them into config items, so they can be inserted into the middle config layer between system rc and user rc.

rcutil: let rccomponents return different types of configs (API) The next patches will convert environ to raw config items, and insert the config items between systemrcpath and userrcpath. This patch teaches rccomponents to return the type information so the caller could distinguish between "path" and raw config "items".

rcutil: rename rcpath to rccomponents (API)

rcutil: extract rc directory listing logic The logic of listing a ".rc" directory is duplicated in two functions, extract it to a single function to make the code cleaner.

rcutil: split osrcpath to return default.d paths (API) After this change, there are 3 rcpath functions: - defaultrcpath - systemrcpath - userrcpath This will allow us to insert another config layer in the middle.