procutil: compare fd number to see if stdio protection is needed (issue5992) When I wrote this function for commandserver at 69f86b937035, testing object identity was suffice, and I was sloppy enough not to compare fileno() values. However, it doesn't work in chg session because chgserver reopens stdio to apply new buffering mode. This patch partially fixes the issue 5992. Still we have another problem in chgui._runsystem().

test-ssh: show that stdio redirection doesn't work with chg Running tests with --chg doesn't mean all hg invocations are replaced by chg. This patch explicitly adds the test for "chg serve --stdio", which does weird stdio dance.

revset: make heads(commonancestors(x + x^)) be x^, not x Differential Revision: https://phab.mercurial-scm.org/D4742

revset: add tests of heads(commonancestors(..)) The second-to-last one shows the same bug as commonancestors(..): the result should be 8, not 9. Differential Revision: https://phab.mercurial-scm.org/D4741

revset: reword commonancestor()'s help The new version seems a bit more consistent with other doc comments, and feels clearer to me (doesn't explain "commonancestors(set)" as "common ancestors of set"). Differential Revision: https://phab.mercurial-scm.org/D4740

revset: remove part of the commonancestors() comment The reason is that: - it shows up in "hg help revset", but it doesn't look like documentation targeted at users - it doesn't make sense to me: it doesn't say what happens with < 2 revisions, and is not quite right because my understanding is that this revset was created precisely because "::x and ::y" was not quite the same (when x and y don't evaluate to singletons). Differential Revision: https://phab.mercurial-scm.org/D4739

revset: make commonancestors(x + x^) be ::(x^), not ::x Differential Revision: https://phab.mercurial-scm.org/D4738