$ hg log --rev 'sort(all(), "-random")' | wc -l
\s*8 (re)
$ hg log --rev 'sort(all(), "random", random.seed=celeste)'
+ 0 b12 m111 u112 111 10800
+ 4 b111 m112 u111 110 14400
+ 2 b111 m11 u12 111 3600
6 b111 t2 tu 130 0
+ 1 b11 m12 u111 112 7200
7 b111 t3 tu 130 0
- 4 b111 m112 u111 110 14400
- 3 b112 m111 u11 120 0
5 b111 t1 tu 130 0
- 0 b12 m111 u112 111 10800
- 1 b11 m12 u111 112 7200
- 2 b111 m11 u12 111 3600
+ 3 b112 m111 u11 120 0
$ hg log --rev 'first(sort(all(), "random", random.seed=celeste))'
- 6 b111 t2 tu 130 0
+ 0 b12 m111 u112 111 10800
topographical sorting can't be combined with other sort keys, and you can't