tests: demonstrate how `hg unamend` fails on merge commits

When `hg unamend` is run on a merge commit, it seems that it loses the
changes from the second parent.

Differential Revision: https://phab.mercurial-scm.org/D12086

tests/test-unamend.t

@@ -1,423 +1,450 b''
 Test for command `hg unamend` which lives in uncommit extension
 ===============================================================
 
   $ cat >> $HGRCPATH << EOF
   > [alias]
   > glog = log -G -T '{rev}:{node|short}  {desc}'
   > [experimental]
   > evolution = createmarkers, allowunstable
   > evolution.allowdivergence = true
   > [extensions]
   > rebase =
   > amend =
   > uncommit =
   > EOF
 
 Repo Setup
 
   $ hg init repo
   $ cd repo
   $ for ch in a b c d e f g h; do touch $ch; echo "foo" >> $ch; hg ci -Aqm "Added "$ch; done
 
   $ hg glog
   @  7:ec2426147f0e  Added h
   |
   o  6:87d6d6676308  Added g
   |
   o  5:825660c69f0c  Added f
   |
   o  4:aa98ab95a928  Added e
   |
   o  3:62615734edd5  Added d
   |
   o  2:28ad74487de9  Added c
   |
   o  1:29becc82797a  Added b
   |
   o  0:18d04c59bb5d  Added a
   
 Trying to unamend when there was no amend done
 
   $ hg unamend
   abort: changeset must have one predecessor, found 0 predecessors
   [10]
 
 Unamend on clean wdir and tip
 
   $ echo "bar" >> h
   $ hg amend
 
   $ hg exp
   # HG changeset patch
   # User test
   # Date 0 0
   #      Thu Jan 01 00:00:00 1970 +0000
   # Node ID c9fa1a715c1b7661c0fafb362a9f30bd75878d7d
   # Parent  87d6d66763085b629e6d7ed56778c79827273022
   Added h
   
   diff -r 87d6d6676308 -r c9fa1a715c1b h
   --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
   +++ b/h	Thu Jan 01 00:00:00 1970 +0000
   @@ -0,0 +1,2 @@
   +foo
   +bar
 
   $ hg glog --hidden
   @  8:c9fa1a715c1b  Added h
   |
   | x  7:ec2426147f0e  Added h
   |/
   o  6:87d6d6676308  Added g
   |
   o  5:825660c69f0c  Added f
   |
   o  4:aa98ab95a928  Added e
   |
   o  3:62615734edd5  Added d
   |
   o  2:28ad74487de9  Added c
   |
   o  1:29becc82797a  Added b
   |
   o  0:18d04c59bb5d  Added a
   
   $ hg unamend
   $ hg glog --hidden
   @  9:46d02d47eec6  Added h
   |
   | x  8:c9fa1a715c1b  Added h
   |/
   | x  7:ec2426147f0e  Added h
   |/
   o  6:87d6d6676308  Added g
   |
   o  5:825660c69f0c  Added f
   |
   o  4:aa98ab95a928  Added e
   |
   o  3:62615734edd5  Added d
   |
   o  2:28ad74487de9  Added c
   |
   o  1:29becc82797a  Added b
   |
   o  0:18d04c59bb5d  Added a
   
   $ hg diff
   diff -r 46d02d47eec6 h
   --- a/h	Thu Jan 01 00:00:00 1970 +0000
   +++ b/h	Thu Jan 01 00:00:00 1970 +0000
   @@ -1,1 +1,2 @@
    foo
   +bar
 
   $ hg exp
   # HG changeset patch
   # User test
   # Date 0 0
   #      Thu Jan 01 00:00:00 1970 +0000
   # Node ID 46d02d47eec6ca096b8dcab3f8f5579c40c3dd9a
   # Parent  87d6d66763085b629e6d7ed56778c79827273022
   Added h
   
   diff -r 87d6d6676308 -r 46d02d47eec6 h
   --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
   +++ b/h	Thu Jan 01 00:00:00 1970 +0000
   @@ -0,0 +1,1 @@
   +foo
 
   $ hg status
   M h
 
   $ hg log -r . -T '{extras % "{extra}\n"}' --config alias.log=log
   branch=default
   unamend_source=c9fa1a715c1b7661c0fafb362a9f30bd75878d7d
 
 Using unamend to undo an unamed (intentional)
 
   $ hg unamend
   $ hg exp
   # HG changeset patch
   # User test
   # Date 0 0
   #      Thu Jan 01 00:00:00 1970 +0000
   # Node ID 850ddfc1bc662997ec6094ada958f01f0cc8070a
   # Parent  87d6d66763085b629e6d7ed56778c79827273022
   Added h
   
   diff -r 87d6d6676308 -r 850ddfc1bc66 h
   --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
   +++ b/h	Thu Jan 01 00:00:00 1970 +0000
   @@ -0,0 +1,2 @@
   +foo
   +bar
   $ hg diff
 
 Unamend on a dirty working directory
 
   $ echo "bar" >> a
   $ hg amend
   $ echo "foobar" >> a
   $ echo "bar" >> b
   $ hg status
   M a
   M b
 
   $ hg unamend
 
   $ hg status
   M a
   M b
 
   $ hg diff
   diff -r ec338db45d51 a
   --- a/a	Thu Jan 01 00:00:00 1970 +0000
   +++ b/a	Thu Jan 01 00:00:00 1970 +0000
   @@ -1,1 +1,3 @@
    foo
   +bar
   +foobar
   diff -r ec338db45d51 b
   --- a/b	Thu Jan 01 00:00:00 1970 +0000
   +++ b/b	Thu Jan 01 00:00:00 1970 +0000
   @@ -1,1 +1,2 @@
    foo
   +bar
 
 Unamending an added file
 
   $ hg ci -m "Added things to a and b"
   $ echo foo > bar
   $ hg add bar
   $ hg amend
 
   $ hg unamend
   $ hg status
   A bar
 
   $ hg revert --all
   forgetting bar
 
 Unamending a removed file
 
   $ hg remove a
   $ hg amend
 
   $ hg unamend
   $ hg status
   R a
   ? bar
 
   $ hg revert --all
   undeleting a
 
 Unamending an added file with dirty wdir status
 
   $ hg add bar
   $ hg amend
   $ echo bar >> bar
   $ hg status
   M bar
 
   $ hg unamend
   $ hg status
   A bar
   $ hg diff
   diff -r 7f79409af972 bar
   --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
   +++ b/bar	Thu Jan 01 00:00:00 1970 +0000
   @@ -0,0 +1,2 @@
   +foo
   +bar
 
   $ hg revert --all
   forgetting bar
   $ rm bar
 
 Unamending in middle of a stack
 
   $ hg glog
   @  19:7f79409af972  Added things to a and b
   |
   o  12:ec338db45d51  Added h
   |
   o  6:87d6d6676308  Added g
   |
   o  5:825660c69f0c  Added f
   |
   o  4:aa98ab95a928  Added e
   |
   o  3:62615734edd5  Added d
   |
   o  2:28ad74487de9  Added c
   |
   o  1:29becc82797a  Added b
   |
   o  0:18d04c59bb5d  Added a
   
   $ hg up 5
   2 files updated, 0 files merged, 2 files removed, 0 files unresolved
   $ echo bar >> f
   $ hg amend
   3 new orphan changesets
   $ hg rebase -s 6 -d . -q
 
   $ hg glog
   o  23:03ddd6fc5af1  Added things to a and b
   |
   o  22:3e7b64ee157b  Added h
   |
   o  21:49635b68477e  Added g
   |
   @  20:93f0e8ffab32  Added f
   |
   o  4:aa98ab95a928  Added e
   |
   o  3:62615734edd5  Added d
   |
   o  2:28ad74487de9  Added c
   |
   o  1:29becc82797a  Added b
   |
   o  0:18d04c59bb5d  Added a
   
 
   $ hg --config experimental.evolution=createmarkers unamend
   abort: cannot unamend changeset, as that will orphan 3 descendants
   (see 'hg help evolution.instability')
   [10]
 
   $ hg unamend
   3 new orphan changesets
 
 Trying to unamend a public changeset
 
   $ hg up -C 23
   5 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg phase -r . -p
   1 new phase-divergent changesets
   $ hg unamend
   abort: cannot unamend public changesets: 03ddd6fc5af1
   (see 'hg help phases' for details)
   [10]
 
 Testing whether unamend retains copies or not
 
   $ hg status
 
   $ hg mv a foo
 
   $ hg ci -m "Moved a to foo"
   $ hg exp --git
   # HG changeset patch
   # User test
   # Date 0 0
   #      Thu Jan 01 00:00:00 1970 +0000
   # Node ID cfef290346fbee5126313d7e1aab51d877679b09
   # Parent  03ddd6fc5af19e028c44a2fd6d790dd22712f231
   Moved a to foo
   
   diff --git a/a b/foo
   rename from a
   rename to foo
 
   $ hg mv b foobar
   $ hg diff --git
   diff --git a/b b/foobar
   rename from b
   rename to foobar
   $ hg amend
 
   $ hg exp --git
   # HG changeset patch
   # User test
   # Date 0 0
   #      Thu Jan 01 00:00:00 1970 +0000
   # Node ID eca050985275bb271ce3092b54e56ea5c85d29a3
   # Parent  03ddd6fc5af19e028c44a2fd6d790dd22712f231
   Moved a to foo
   
   diff --git a/a b/foo
   rename from a
   rename to foo
   diff --git a/b b/foobar
   rename from b
   rename to foobar
 
   $ hg mv c wat
   $ hg unamend
 
   $ hg verify -v
   repository uses revlog format 1
   checking changesets
   checking manifests
   crosschecking files in changesets and manifests
   checking files
   checked 28 changesets with 16 changes to 11 files
 
 Retained copies in new prdecessor commit
 
   $ hg exp --git
   # HG changeset patch
   # User test
   # Date 0 0
   #      Thu Jan 01 00:00:00 1970 +0000
   # Node ID 552e3af4f01f620f88ca27be1f898316235b736a
   # Parent  03ddd6fc5af19e028c44a2fd6d790dd22712f231
   Moved a to foo
   
   diff --git a/a b/foo
   rename from a
   rename to foo
 
 Retained copies in working directoy
 
   $ hg diff --git
   diff --git a/b b/foobar
   rename from b
   rename to foobar
   diff --git a/c b/wat
   rename from c
   rename to wat
   $ hg revert -qa
   $ rm foobar wat
 
 Rename a->b, then amend b->c. After unamend, should look like b->c.
 
   $ hg co -q 0
   $ hg mv a b
   $ hg ci -qm 'move to a b'
   $ hg mv b c
   $ hg amend
   $ hg unamend
   $ hg st --copies --change .
   A b
     a
   R a
   $ hg st --copies
   A c
     b
   R b
   $ hg revert -qa
   $ rm c
 
 Rename a->b, then amend b->c, and working copy change c->d. After unamend, should look like b->d
 
   $ hg co -q 0
   $ hg mv a b
   $ hg ci -qm 'move to a b'
   warning: commit already existed in the repository!
   $ hg mv b c
   $ hg amend
   warning: commit already existed in the repository!
   $ hg mv c d
   $ hg unamend
   $ hg st --copies --change .
   A b
     a
   R a
   $ hg st --copies
   A d
     b
   R b
+
+Try to unamend a merge
+
+  $ cd ..
+  $ hg init merge
+  $ cd merge
+  $ echo initial > initial
+  $ hg ci -Aqm initial
+  $ echo left > left
+  $ hg ci -Aqm left
+  $ hg co -q 0
+  $ echo right > right
+  $ hg ci -Aqm right
+  $ hg merge -q 1
+  $ hg ci -m merge
+  $ echo accidental > initial
+  $ hg st --rev 1 --rev .
+  A right
+  $ hg st --rev 2 --rev .
+  A left
+  $ hg amend
+  $ hg unamend
+  $ hg st --rev 1 --rev .
+  A right
+  R left (known-bad-output !)
+  $ hg st --rev 2 --rev .
+  A left (missing-correct-output !)