destination: use the correct abort class for error These errors have been in Mercurial long enough. Having them will make the coming changesets simpler.

topic: list the number of head when --verbose is used Displaying more information in the topic list is useful, we continue with the number of heads on the topics, this will help highlight the problem to users. We only display head if there is more than one.

topic: list the number of troubled changesets when --verbose is used Displaying more information in the topic list is useful, we continue with the number of troubled changesets. This will help people to spot topics that needs evolution, for example after a pull.

topic: list the number of changesets when --verbose is used Displaying more information in the topic list is useful, we start with the most obvious: number of non-obsolete changeset in the topic.

topic: add color for the active topic We reuse the same color that the one used for the active bookmark.

topic: add formatter support Using formatter to output the list of topic will add support for color and richer templater. We add some test for output control. We introduce a dedicated test to help with coming more complexe output.

topic: extract the code listing all topics The code will become more complexe with formatter support and additional data in the verbose output. We extract the code in its own function first.

stack: introduce and explicite command to display the stack If is worth testing having the feature lives outside 'hg topic --list'. The 'stack' name is sub optimal because the conflict with 'status'. using "hg st" would still work as 'st' is hard coded, but this mean 'hg stack' has no short version.

testedwith: update to 3.9 This is might still 3.7 compatible but I'm no longer running the test and I would says the user base is small enough to not care.

topic: make sure we have the 'wlock' when setting topic We where writing the '.hg/topic' file without a lot. That was bad.

cleanup: removed unused mercurial.util import

compat: tolerate missing rebase extension

compat: mercurial dropped alias for hashlib.sha1

destination: add an XXX about handling destspace in destmerge This that we hopefully do not forget about this.

update: calculate 'partial' as core does

discovery: flake8

destination: flake8

style: update __init__.py

compat: adapt to the new destspace argument of destmerge The argument is currently ignored in the topic case for simplicity, but we properly accept it and propagate it to the original function to prevent crash and behavior regression in the non-topic case.

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.