backout: deprecate/hide support for backing out merges
This has never worked usefully:
- it can't undo a completely unwanted merge, as it leaves the merge in the DAG
- it can't undo a faulty merge as that means doing a merge correctly,
not simply reverting to one or the other parent
Both of these kinds of merge also require coordinated action among
developers to avoid the bad merge continuing to affect future merges,
so we should stop pretending that backout is of any help here.
As backing out a merge now requires a hidden option, it can't be done
by accident, but will continue to 'work' for anyone who's already
dependent on --parent for some unknown reason.
Setup extension:
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq =" >> $HGRCPATH
$ echo "[mq]" >> $HGRCPATH
$ echo "git = keep" >> $HGRCPATH
Test merge with mq changeset as the second parent:
$ hg init m
$ cd m
$ touch a b c
$ hg add a
$ hg commit -m a
$ hg add b
$ hg qnew -d "0 0" b
$ hg update 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg add c
$ hg commit -m c
created new head
$ hg merge
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg commit -m merge
abort: cannot commit over an applied mq patch
[255]
$ cd ..
Issue529: mq aborts when merging patch deleting files
$ checkundo()
> {
> if [ -f .hg/store/undo ]; then
> echo ".hg/store/undo still exists"
> fi
> }
Commit two dummy files in "init" changeset:
$ hg init t
$ cd t
$ echo a > a
$ echo b > b
$ hg ci -Am init
adding a
adding b
$ hg tag -l init
Create a patch removing a:
$ hg qnew rm_a
$ hg rm a
$ hg qrefresh -m "rm a"
Save the patch queue so we can merge it later:
$ hg qsave -c -e
copy $TESTTMP/t/.hg/patches to $TESTTMP/t/.hg/patches.1
$ checkundo
Update b and commit in an "update" changeset:
$ hg up -C init
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo b >> b
$ hg st
M b
$ hg ci -m update
created new head
# Here, qpush used to abort with :
# The system cannot find the file specified => a
$ hg manifest
a
b
$ hg qpush -a -m
merging with queue at: $TESTTMP/t/.hg/patches.1
applying rm_a
now at: rm_a
$ checkundo
$ hg manifest
b
Ensure status is correct after merge:
$ hg qpop -a
popping rm_a
popping .hg.patches.merge.marker
patch queue now empty
$ cd ..
Classic MQ merge sequence *with an explicit named queue*:
$ hg init t2
$ cd t2
$ echo '[diff]' > .hg/hgrc
$ echo 'nodates = 1' >> .hg/hgrc
$ echo a > a
$ hg ci -Am init
adding a
$ echo b > a
$ hg ci -m changea
$ hg up -C 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg cp a aa
$ echo c >> a
$ hg qnew --git -f -e patcha
$ echo d >> a
$ hg qnew -d '0 0' -f -e patcha2
Create the reference queue:
$ hg qsave -c -e -n refqueue
copy $TESTTMP/t2/.hg/patches to $TESTTMP/t2/.hg/refqueue
$ hg up -C 1
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
Merge:
$ HGMERGE=internal:other hg qpush -a -m -n refqueue
merging with queue at: $TESTTMP/t2/.hg/refqueue
applying patcha
patching file a
Hunk #1 FAILED at 0
1 out of 1 hunks FAILED -- saving rejects to file a.rej
patch failed, unable to continue (try -v)
patch failed, rejects left in working dir
patch didn't work out, merging patcha
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
0 files updated, 2 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
applying patcha2
now at: patcha2
Check patcha is still a git patch:
$ cat .hg/patches/patcha
# HG changeset patch
# Parent d3873e73d99ef67873dac33fbcc66268d5d2b6f4
diff --git a/a b/a
--- a/a
+++ b/a
@@ -1,1 +1,2 @@
-b
+a
+c
diff --git a/a b/aa
copy from a
copy to aa
--- a/a
+++ b/aa
@@ -1,1 +1,1 @@
-b
+a
Check patcha2 is still a regular patch:
$ cat .hg/patches/patcha2
# HG changeset patch
# Parent ???????????????????????????????????????? (glob)
# Date 0 0
diff -r ???????????? -r ???????????? a (glob)
--- a/a
+++ b/a
@@ -1,2 +1,3 @@
a
c
+d
$ cd ..