diff: pass a diff hunks filter function from changeset_printer to patch.diff() We add a 'hunksfilterfn' keyword argument in all functions of the call stack from changeset_printer.show() to patch.diff(). This is a callable that will be used to filter out hunks by line range and will be used in the "-L/--line-range" option of "hg log" command introduced in the following changesets.

diff: also yield file context objects in patch.trydiff() (API) And retrieve them in patch.diffhunks(). We'll use these in forthcoming changesets to filter diff hunks by line range.

revset: extract a parsefollowlinespattern helper function We'll need the same logic in forthcoming changeset to handle --line-range option in 'hg log' command. The function lives in scmutil.py (rather than util.py) as it uses match and pathutil modules.

obsfate: add obsfate to default mapfile Use the verbosity aware template keyword introduced earlier. It has the nice property of being verbosity dependent but in order to customize the obsfate part, users will need to replace the lobsfate definition from default mapfile with the one using template functions (by copying the one from test-obsmarker- template.t for example). As it's a more advanced use-case, I'm more inclined to have the same code for the {obsfate} keyword, in the changeset printer and in the default mapfile for consistency. But, the definition in default mapfile could be replaced with one based on template filter to obsfate output customization if it is a big need for users.

log: add obsfate by default in changeset printer Having an obsfate by default in log will be useful for users to understand why they have obsolete and unstable changesets. Obsfate will only be shown for obsolete changesets, which only happens if people opt-in to experimental feature. But when obsolete changeset are visible, it is very useful to understand where they are. Having it in log could be sufficient for most people, so they don't have to learn a new command (like obslog which is itself useful in case of divergences). For example, when pulling and working directory parent become obsolete: $ hg pull ... working directory parent is obsolete! (f936c1697205) This message comes from the Evolve extension. Obsfate would comes handy: $ hg log -G o changeset: 2:6f91013c5136 | tag: tip | parent: 0:4ef7b558f3ec | user: Boris Feld <boris.feld@octobus.net> | date: Mon Oct 09 16:00:27 2017 +0200 | summary: A | | @ changeset: 1:f936c1697205 |/ user: Boris Feld <boris.feld@octobus.net> | date: Mon Oct 09 16:00:27 2017 +0200 | obsfate: rewritten using amend as 2:6f91013c5136 | summary: -A | o changeset: 0:feb4dd822b8c user: Boris Feld <boris.feld@octobus.net> date: Tue Oct 09 16:00:00 2017 +0200 summary: ROOT And once we update, we don't have an obsolete changeset in the log anymore so we don't show obsfate anymore, most users won't see obsfate often if they don't have obsolete changeset often: @ changeset: 2:6f91013c5136 | tag: tip | parent: 0:4ef7b558f3ec | user: Boris Feld <boris.feld@octobus.net> | date: Mon Oct 09 16:00:27 2017 +0200 | summary: A | o changeset: 0:feb4dd822b8c user: Boris Feld <boris.feld@octobus.net> date: Tue Oct 09 16:00:00 2017 +0200 summary: ROOT

obsfate: only display date in verbose mode The date is also not that helpful in most cases but we show it in verbose mode.

obsfate: filter out current user if not in verbose Obsolescence is sometimes used only locally so the obs-marker users is always the same. Showing the user in this case does not bring much values. In the case where multiple users rewrite the commit, display the full list of users. Also show all users in verbose mode.

ui: add the possibility to returns None as username in ui In a later patch we want to retrieve the current username or None if it isn't defined. Add the acceptempty parameter instead of catching Abort.

test: test obfate template keyword in test-obsmarker-template.t These test updates are pretty big by themselves so put it in a separate patch for easing the review process.

templatekw: introduce obsfate keyword Introduce an obsfate printer that uses all helpers functions defined in obsutil to get all the obsfate-related data and format a string according to the current format in test-obsmarker-template.t. Then, introduce an obsfate templatekw that uses the obsfateprinter to return a list of strings. The goal is not to replace existing obsfate template functions but to propose a default, good-enough and easily usable obsfate definition for end-users that don't want to customize it. Such output would ultimately get included in the default log output. Here are some output examples for a commit amended: rewritten using amend as 5:a9b1f8652753 by test (at 1970-01-01 00:00 +0000) Next patches will make the output dependent on the verbosity. Exemple of use-cases: For having the obsfate on a single-line between brackets: {if(obsfate, " [{join(obsfate, "; ")}]")} For having the obsfate in several lines: {if(obsfate, "{obsfate % " Obsfate: {fate}\n"}")}