stack: prevent crash when topic is rooted on nullid We exclude null from displayed base. This was causing a crash when trying to display its description (we'll still have to handle the empty description case, but it is now less urgent).

test: add topic on the first 2 changesets too This will be used to add a test for topic rooted on nullid. We introduce this in its own changeset to reduce the noise if the actual changeset.

test: remove comment about new head warning The new head warning was buggy. This was fixed in bdc5bb223b50.

stack: also change the indexing of the t# reference Changeset 61f36480740f changed the index displayed (we now index from 1), but forgot to update the logic used to resolve the 't#' name. This changeset fixes it.

stack: change the ascii symbold for base Now that the children line go upward, '_' is no longer clear as is take the lower part of the line. We go for '^' that use the upper part.

stack: reverse the display order Most mercurial command display the most recent changeset first. We put `hg topic --list` inline with this.

topic: extract display from entry computation We are about to reverse the order of the output (most recent first) so it will be useful.

stack: start indexing at 't1' instead of 't0' I think 't0' could have special meaning (eg: before 't1', but still with topic activated) so let's keep room for that. Indexing from 1 is not crazy anyway.

commit: wrap "commitstatus" to take topic into account The "created new head" message was appearing for every single commit made on a topic. It should now properly only appears when a new head is actually created on a topic.

uisetup: add call to 'topicmap.modsetup' this was forgotten in 99c1a26abf3f. Tests did not broke because the wrapping of cg.apply only have performance impact (cache warmup).

uisetup: move all remaining wrapping into uisetup All our wrapping is now properly done at uisetup time. Hooray.

topicmap: move 'cgapply' wrapping into the topicmap module More gathering of related logic.

topicmap: move the 'usetopicmap' context manager into the topicmap module There is no good reason to not have it gathered with the rest.

patch: move setup of import/export logic into a function The function is now called during uisetup.

patch: remove version compatibility check We don't support anything under 3.7.

patch: document the section about import/export

patch: move import/export wrapping close to the function definition This gather similar logic together.

discovery: move all setup into a 'modsetup' function The various wrappings are moved into a function that live in the module and the function is now properly called during 'uisetup'.

revset: add a ui argument to 'modsetup' This is a gratuitous change for consistency with the function that use it.

revset: run 'modsetup' at uisetup time We are slowly moving away from module time wrapping. These thing should be done in the dedicated 'setup' method called by Mercurial.

destination: rename 'setupdest' to 'modsetup' the topic.revset module use 'modsetup' as a name for its setup function. It looks like a good name, lets unify names toward that.

destination: document 'setupdest' Let's make the role of this function clear.

destination: add a ui argument to 'setupdest' This is a gratuitous change for consistency.

destination: make sure 'setupdest' is the latest function in the module Let's introduce some consistency, end of module seems fine.

topicmap: move to new style import This unify with the new core Mercurial usage and this will make future changes to the imports easier to track.

stack: move to new style import This unify with the new core Mercurial usage and this will make future changes to the imports easier to track.

revset: move to new style import This unify with the new core Mercurial usage and this will make future changes to the imports easier to track.

discovery: move to new style import This unify with the new core Mercurial usage and this will make future changes to the imports easier to track.

destination: move to new style import This unify with the new core Mercurial usage and this will make future changes to the imports easier to track.

init: move to new style import This unify with the new core Mercurial usage and this will make future changes to the imports easier to track.

test: disable the new style rendering for "missing parent" The style kicks in when we display a partial tree. Supporting test running both 3.7 and default with this is painful, we disable the new feature for now.

tests: add pyflakes test