Mercurial > hg > mercurial-source
changeset 33482:f75d0aa5dc83
revset: lookup descendents for negative arguments to ancestor operator
Negative offsets to the `~` operator now search for descendents. The search is
aborted when a node has more than one child as we do not have a definition for
'nth child'. Optionally we can introduce such a notion and take the nth child
ordered by rev number.
The current revset language does provides a short operator for ancestor lookup
but not for descendents. This gives user a simple revset to move to the previous
changeset, e.g. `hg up '.~1'` but not to the 'next' changeset. With this change
userse can now use `.~-1` as a shortcut to move to the next changeset.
This fits better into allowing users to specify revisions via revsets and
avoiding the need for special `hg next` and `hg prev` operations.
The alternative to negative offsets is adding a new operator. We do not have
many operators in ascii left that do not require bash escaping (',', '_', and
'/' come to mind). If we decide that we should add a more convenient short
operator such as ('/', e.g. './1') we can later add it and allow ascendents
lookup via negative numbers.
author | David Soria Parra <davidsp@fb.com> |
---|---|
date | Sat, 27 May 2017 10:25:09 -0700 |
parents | 1b5c61d38a52 |
children | 3afe258fb0fe |
files | mercurial/help/revisions.txt mercurial/revset.py tests/test-revset.t |
diffstat | 3 files changed, 34 insertions(+), 0 deletions(-) [+] |
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--- a/mercurial/help/revisions.txt +++ b/mercurial/help/revisions.txt @@ -97,6 +97,7 @@ ``x~n`` The nth first ancestor of x; ``x~0`` is x; ``x~3`` is ``x^^^``. + For n < 0, the nth unambiguous descendent of x. ``x ## y`` Concatenate strings and identifiers into one string.
--- a/mercurial/revset.py +++ b/mercurial/revset.py @@ -379,12 +379,33 @@ # Like ``ancestors(set)`` but follows only the first parents. return _ancestors(repo, subset, x, followfirst=True) +def _childrenspec(repo, subset, x, n, order): + """Changesets that are the Nth child of a changeset + in set. + """ + cs = set() + for r in getset(repo, fullreposet(repo), x): + for i in range(n): + c = repo[r].children() + if len(c) == 0: + break + if len(c) > 1: + raise error.RepoLookupError( + _("revision in set has more than one child")) + r = c[0] + else: + cs.add(r) + return subset & cs + def ancestorspec(repo, subset, x, n, order): """``set~n`` Changesets that are the Nth ancestor (first parents only) of a changeset in set. """ n = getinteger(n, _("~ expects a number")) + if n < 0: + # children lookup + return _childrenspec(repo, subset, x, -n, order) ps = set() cl = repo.changelog for r in getset(repo, fullreposet(repo), x):
--- a/tests/test-revset.t +++ b/tests/test-revset.t @@ -2975,6 +2975,14 @@ $ log 'merge()^^^' 1 + $ log '(merge() | 0)~-1' + 7 + 1 + $ log 'merge()~-1' + 7 + $ log 'tip~-1' + $ log '(tip | merge())~-1' + 7 $ log 'merge()~0' 6 $ log 'merge()~1' @@ -2995,6 +3003,10 @@ hg: parse error: ^ expects a number 0, 1, or 2 [255] + $ log 'branchpoint()~-1' + abort: revision in set has more than one child! + [255] + Bogus function gets suggestions $ log 'add()' hg: parse error: unknown identifier: add