parents: correct help revset replacements Implementing `hg parents -r REV FILE` correctly is hard. The output can be 0, 1, or 2 revs. First, you can't use parents(), because it sorts its output... Consider: echo $a echo par@rev: `hg log -r "parents($a)" -q` echo p12@rev: `hg log -r "p1($a)+p2($a)" -q` echo parents: `hg parents -q -r $a` (Merge 1 into 0) 3 par@rev: 0:d9612eafe8ec 1:070fe4290d06 p12@rev: 0:d9612eafe8ec 1:070fe4290d06 parents: 0:d9612eafe8ec 1:070fe4290d06 (Merge 4 into 5) 6 par@rev: 4:db73392995c3 5:c26e7dd67644 p12@rev: 5:c26e7dd67644 4:db73392995c3 parents: 5:c26e7dd67644 4:db73392995c3 (Merge 7 into 8) 9 par@rev: 7:d84f47462f70 8:9597bcab36e0 p12@rev: 8:9597bcab36e0 7:d84f47462f70 parents: 8:9597bcab36e0 7:d84f47462f70 You also can't use parents or/p1/p2 alone with a set, as in: -r "parents(::REV and file(FILE))" -r "parents(::REV - REV and file(FILE))" ... because each will return all parents for each candidate revision, and the :: gives too many candidates. Thus, we need a max and a p1/p2. Also, anything of this form: max(::REV - REV and file(FILE)) ... is wrong, because max will return only one revision, and for a proper parents, you need to return two occasionally. Lastly, it doesn't help that `hg parents -r REV FILE` is buggy due to a quirk in filelogs. Here's a repository to consider when evaluating whether your revset is correct: $ hg log -G --template '{rev} {files}\n'; @ 10 a | o 9 a b |\ | o 8 a | | o | 7 a | | +---o 6 b | |/ | o 5 b | | o | 4 b | | +---o 3 | |/ +---o 2 | |/ | o 1 b | o 0 a revs 4 and 5 create a conflict. The conflict is resolved in the same way by both 6 and 9. You would hope that parents around 9/10 would point to 9, but `hg parents` will point to 6 due to the aforementioned bug. Here's the winning solution test script and its output. echo $a; echo rp12-max: `hg log -r "max(::p1($a) and file(b)) + max(::p2($a) and file(b))" -q` 2> /dev/null; echo expected: `hg parents -q -r $a b` 2> /dev/null; Note that for 10, the output differs, but again, this is because of the aforementioned bug. The rp12-max output is "correct", whereas "expected" is just an unfortunate bug. The abort output is due to something else. I'm not sure why someone thought it was important to abort to stdio instead of stderr, but that's really not my problem here. 10 rp12-max: 9:184ebefc2fce expected: 6:dd558142b03f 9 rp12-max: 5:c26e7dd67644 4:db73392995c3 expected: 5:c26e7dd67644 4:db73392995c3 8 rp12-max: 5:c26e7dd67644 expected: 5:c26e7dd67644 7 rp12-max: 4:db73392995c3 expected: 4:db73392995c3 6 rp12-max: 5:c26e7dd67644 4:db73392995c3 expected: 5:c26e7dd67644 4:db73392995c3 5 rp12-max: 1:070fe4290d06 expected: 1:070fe4290d06 4 rp12-max: abort: 'b' not found in manifest! expected: 3 rp12-max: 1:070fe4290d06 expected: 1:070fe4290d06 2 rp12-max: 1:070fe4290d06 expected: 1:070fe4290d06 1 rp12-max: abort: 'b' not found in manifest! expected: 0 rp12-max: abort: 'b' not found in manifest! expected:

--- a/mercurial/commands.py	Mon Dec 28 16:01:31 2015 +0000
+++ b/mercurial/commands.py	Wed Dec 23 19:07:34 2015 +0000
@@ -5303,10 +5303,10 @@
 
     This command is equivalent to::
 
-        hg log -r "parents()" or
-        hg log -r "parents(REV)" or
-        hg log -r "max(file(FILE))" or
-        hg log -r "max(::REV and file(FILE))"
+        hg log -r "p1()+p2()" or
+        hg log -r "p1(REV)+p2(REV)" or
+        hg log -r "max(::p1() and file(FILE))+max(::p2() and file(FILE))" or
+        hg log -r "max(::p1(REV) and file(FILE))+max(::p2(REV) and file(FILE))"
 
     See :hg:`summary` and :hg:`help revsets` for related information.