--- a/tests/test-amend.t Tue Jun 29 14:02:34 2021 -0700
+++ b/tests/test-amend.t Tue Jun 29 13:58:18 2021 -0700
@@ -251,11 +251,46 @@
$ hg amend -m divergent --config experimental.evolution.allowdivergence=true
2 new content-divergent changesets
+Amending pruned part of split commit does not cause divergence (issue6262)
+
+ $ hg debugobsolete $(hg log -T '{node}' -r .)
+ 1 new obsolescence markers
+ obsoleted 1 changesets
+ $ hg co '.^'
+ 0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+ $ node_B=$(hg log -T '{node}' -r 4)
+ $ hg revert -r $node_B -a
+ adding B
+ adding bar
+ $ hg ci -m B-split1
+ created new head
+ $ node_B_split1=$(hg log -T '{node}' -r .)
+ $ hg co '.^'
+ 0 files updated, 0 files merged, 2 files removed, 0 files unresolved
+ $ hg revert -r 4 -a
+ adding B
+ adding bar
+ $ hg ci -m B-split2
+ created new head
+ $ node_B_split2=$(hg log -T '{node}' -r .)
+ $ hg debugobsolete $node_B $node_B_split1 $node_B_split2
+ 1 new obsolescence markers
+ obsoleted 1 changesets
+ $ hg debugobsolete $node_B_split2
+ 1 new obsolescence markers
+ obsoleted 1 changesets
+ $ hg co --hidden $node_B_split2
+ 0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+ $ hg amend -m 'revived B-split2'
+ abort: cannot amend 809fe227532f, as that creates content-divergence with c68306a86921, from 16084da537dd (known-bad-output !)
+ (add --verbose for details or see 'hg help evolution.instability') (known-bad-output !)
+ [10]
+
Hidden common predecessor of divergence does not cause crash
First create C1 as a pruned successor of C
$ hg co C
- 1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+ 2 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg amend -m C1
$ hg tag --local C1
$ hg debugobsolete $(hg log -T '{node}' -r C1)