view tests/test-rebase-conflicts.t @ 36426:23d12524a202

http: drop custom http client logic

Eight and a half years ago, as my starter bug on code.google.com, I
investigated a mysterious "broken pipe" error from seemingly random
clients[0]. That investigation revealed a tragic story: the Python
standard library's httplib was (and remains) barely functional. During
large POSTs, if a server responds early with an error (even a
permission denied error!) the client only notices that the server
closed the connection and everything breaks. Such server behavior is
implicitly legal under RFC 2616 (the latest HTTP RFC as of when I was
last working on this), and my understanding is that later RFCs have
made it explicitly legal to respond early with any status code outside
the 2xx range.

I embarked, probably foolishly, on a journey to write a new http
library with better overall behavior. The http library appears to work
well in most cases, but it can get confused in the presence of
proxies, and it depends on select(2) which limits its utility if a lot
of file descriptors are open. I haven't touched the http library in
almost two years, and in the interim the Python community has
discovered a better way[1] of writing network code. In theory some day
urllib3 will have its own home-grown http library built on h11[2], or
we could do that. Either way, it's time to declare our current
confusingly-named "http2" client logic and move on. I do hope to
revisit this some day: it's still garbage that we can't even respond
with a 401 or 403 without reading the entire POST body from the
client, but the goalposts on writing a new http client library have
moved substantially. We're almost certainly better off just switching
to requests and eventually picking up their http fixes than trying to
live with something that realistically only we'll ever use. Another
approach would be to write an adapter so that Mercurial can use pycurl
if it's installed. Neither of those approaches seem like they should
be investigated prior to a release of Mercurial that works on Python
3: that's where the mindshare is going to be for any improvements to
the state of the http client art.

0: http://web.archive.org/web/20130501031801/http://code.google.com/p/support/issues/detail?id=2716
1: http://sans-io.readthedocs.io/
2: https://github.com/njsmith/h11

Differential Revision: https://phab.mercurial-scm.org/D2444

  $ cat >> $HGRCPATH <<EOF
  > [format]
  > usegeneraldelta=yes
  > [extensions]
  > rebase=
  > drawdag=$TESTDIR/drawdag.py
  > 
  > [phases]
  > publish=False
  > 
  > [alias]
  > tglog = log -G --template "{rev}:{phase} '{desc}' {branches} {bookmarks}\n"
  > EOF

  $ hg init a
  $ cd a
  $ echo c1 >common
  $ hg add common
  $ hg ci -m C1

  $ echo c2 >>common
  $ hg ci -m C2

  $ echo c3 >>common
  $ hg ci -m C3

  $ hg up -q -C 1

  $ echo l1 >>extra
  $ hg add extra
  $ hg ci -m L1
  created new head

  $ sed -e 's/c2/l2/' common > common.new
  $ mv common.new common
  $ hg ci -m L2

  $ echo l3 >> extra2
  $ hg add extra2
  $ hg ci -m L3
  $ hg bookmark mybook

  $ hg phase --force --secret 4

  $ hg tglog
  @  5:secret 'L3'  mybook
  |
  o  4:secret 'L2'
  |
  o  3:draft 'L1'
  |
  | o  2:draft 'C3'
  |/
  o  1:draft 'C2'
  |
  o  0:draft 'C1'
  
Try to call --continue:

  $ hg rebase --continue
  abort: no rebase in progress
  [255]

Conflicting rebase:

  $ hg rebase -s 3 -d 2
  rebasing 3:3163e20567cc "L1"
  rebasing 4:46f0b057b5c0 "L2"
  merging common
  warning: conflicts while merging common! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]

  $ hg status --config commands.status.verbose=1
  M common
  ? common.orig
  # The repository is in an unfinished *rebase* state.
  
  # Unresolved merge conflicts:
  # 
  #     common
  # 
  # To mark files as resolved:  hg resolve --mark FILE
  
  # To continue:                hg rebase --continue
  # To abort:                   hg rebase --abort
  

Try to continue without solving the conflict:

  $ hg rebase --continue
  abort: unresolved merge conflicts (see 'hg help resolve')
  [255]

Conclude rebase:

  $ echo 'resolved merge' >common
  $ hg resolve -m common
  (no more unresolved files)
  continue: hg rebase --continue
  $ hg rebase --continue
  already rebased 3:3163e20567cc "L1" as 3e046f2ecedb
  rebasing 4:46f0b057b5c0 "L2"
  rebasing 5:8029388f38dc "L3" (mybook)
  saved backup bundle to $TESTTMP/a/.hg/strip-backup/3163e20567cc-5ca4656e-rebase.hg

  $ hg tglog
  @  5:secret 'L3'  mybook
  |
  o  4:secret 'L2'
  |
  o  3:draft 'L1'
  |
  o  2:draft 'C3'
  |
  o  1:draft 'C2'
  |
  o  0:draft 'C1'
  
Check correctness:

  $ hg cat -r 0 common
  c1

  $ hg cat -r 1 common
  c1
  c2

  $ hg cat -r 2 common
  c1
  c2
  c3

  $ hg cat -r 3 common
  c1
  c2
  c3

  $ hg cat -r 4 common
  resolved merge

  $ hg cat -r 5 common
  resolved merge

Bookmark stays active after --continue
  $ hg bookmarks
   * mybook                    5:d67b21408fc0

  $ cd ..

Check that the right ancestors is used while rebasing a merge (issue4041)

  $ hg clone "$TESTDIR/bundles/issue4041.hg" issue4041
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 11 changesets with 8 changes to 3 files (+1 heads)
  new changesets 24797d4f68de:2f2496ddf49d
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd issue4041
  $ hg log -G
  o    changeset:   10:2f2496ddf49d
  |\   branch:      f1
  | |  tag:         tip
  | |  parent:      7:4c9fbe56a16f
  | |  parent:      9:e31216eec445
  | |  user:        szhang
  | |  date:        Thu Sep 05 12:59:39 2013 -0400
  | |  summary:     merge
  | |
  | o  changeset:   9:e31216eec445
  | |  branch:      f1
  | |  user:        szhang
  | |  date:        Thu Sep 05 12:59:10 2013 -0400
  | |  summary:     more changes to f1
  | |
  | o    changeset:   8:8e4e2c1a07ae
  | |\   branch:      f1
  | | |  parent:      2:4bc80088dc6b
  | | |  parent:      6:400110238667
  | | |  user:        szhang
  | | |  date:        Thu Sep 05 12:57:59 2013 -0400
  | | |  summary:     bad merge
  | | |
  o | |  changeset:   7:4c9fbe56a16f
  |/ /   branch:      f1
  | |    parent:      2:4bc80088dc6b
  | |    user:        szhang
  | |    date:        Thu Sep 05 12:54:00 2013 -0400
  | |    summary:     changed f1
  | |
  | o  changeset:   6:400110238667
  | |  branch:      f2
  | |  parent:      4:12e8ec6bb010
  | |  user:        szhang
  | |  date:        Tue Sep 03 13:58:02 2013 -0400
  | |  summary:     changed f2 on f2
  | |
  | | @  changeset:   5:d79e2059b5c0
  | | |  parent:      3:8a951942e016
  | | |  user:        szhang
  | | |  date:        Tue Sep 03 13:57:39 2013 -0400
  | | |  summary:     changed f2 on default
  | | |
  | o |  changeset:   4:12e8ec6bb010
  | |/   branch:      f2
  | |    user:        szhang
  | |    date:        Tue Sep 03 13:57:18 2013 -0400
  | |    summary:     created f2 branch
  | |
  | o  changeset:   3:8a951942e016
  | |  parent:      0:24797d4f68de
  | |  user:        szhang
  | |  date:        Tue Sep 03 13:57:11 2013 -0400
  | |  summary:     added f2.txt
  | |
  o |  changeset:   2:4bc80088dc6b
  | |  branch:      f1
  | |  user:        szhang
  | |  date:        Tue Sep 03 13:56:20 2013 -0400
  | |  summary:     added f1.txt
  | |
  o |  changeset:   1:ef53c9e6b608
  |/   branch:      f1
  |    user:        szhang
  |    date:        Tue Sep 03 13:55:26 2013 -0400
  |    summary:     created f1 branch
  |
  o  changeset:   0:24797d4f68de
     user:        szhang
     date:        Tue Sep 03 13:55:08 2013 -0400
     summary:     added default.txt
  
  $ hg rebase -s9 -d2 --debug # use debug to really check merge base used
  rebase onto 4bc80088dc6b starting from e31216eec445
  rebasing on disk
  rebase status stored
  rebasing 9:e31216eec445 "more changes to f1"
   future parents are 2 and -1
  rebase status stored
   update to 2:4bc80088dc6b
  resolving manifests
   branchmerge: False, force: True, partial: False
   ancestor: d79e2059b5c0+, local: d79e2059b5c0+, remote: 4bc80088dc6b
   f2.txt: other deleted -> r
  removing f2.txt
   f1.txt: remote created -> g
  getting f1.txt
   merge against 9:e31216eec445
     detach base 8:8e4e2c1a07ae
    searching for copies back to rev 3
    unmatched files in other (from topological common ancestor):
     f2.txt
  resolving manifests
   branchmerge: True, force: True, partial: False
   ancestor: 8e4e2c1a07ae, local: 4bc80088dc6b+, remote: e31216eec445
   f1.txt: remote is newer -> g
  getting f1.txt
  committing files:
  f1.txt
  committing manifest
  committing changelog
  updating the branch cache
  rebased as 19c888675e13
  rebasing 10:2f2496ddf49d "merge" (tip)
   future parents are 11 and 7
  rebase status stored
   already in destination
   merge against 10:2f2496ddf49d
     detach base 9:e31216eec445
    searching for copies back to rev 3
    unmatched files in other (from topological common ancestor):
     f2.txt
  resolving manifests
   branchmerge: True, force: True, partial: False
   ancestor: e31216eec445, local: 19c888675e13+, remote: 2f2496ddf49d
   f1.txt: remote is newer -> g
  getting f1.txt
  committing files:
  f1.txt
  committing manifest
  committing changelog
  updating the branch cache
  rebased as 2a7f09cac94c
  rebase merging completed
  update back to initial working directory parent
  resolving manifests
   branchmerge: False, force: False, partial: False
   ancestor: 2a7f09cac94c, local: 2a7f09cac94c+, remote: d79e2059b5c0
   f1.txt: other deleted -> r
  removing f1.txt
   f2.txt: remote created -> g
  getting f2.txt
  2 changesets found
  list of changesets:
  e31216eec445e44352c5f01588856059466a24c9
  2f2496ddf49d69b5ef23ad8cf9fb2e0e4faf0ac2
  bundle2-output-bundle: "HG20", (1 params) 2 parts total
  bundle2-output-part: "changegroup" (params: 1 mandatory 1 advisory) streamed payload
  bundle2-output-part: "phase-heads" 24 bytes payload
  saved backup bundle to $TESTTMP/issue4041/.hg/strip-backup/e31216eec445-15f7a814-rebase.hg
  3 changesets found
  list of changesets:
  4c9fbe56a16f30c0d5dcc40ec1a97bbe3325209c
  19c888675e133ab5dff84516926a65672eaf04d9
  2a7f09cac94c7f4b73ebd5cd1a62d3b2e8e336bf
  bundle2-output-bundle: "HG20", 2 parts total
  bundle2-output-part: "changegroup" (params: 1 mandatory 1 advisory) streamed payload
  bundle2-output-part: "phase-heads" 24 bytes payload
  adding branch
  bundle2-input-bundle: with-transaction
  bundle2-input-part: "changegroup" (params: 1 mandatory 1 advisory) supported
  adding changesets
  add changeset 4c9fbe56a16f
  add changeset 19c888675e13
  add changeset 2a7f09cac94c
  adding manifests
  adding file changes
  adding f1.txt revisions
  added 2 changesets with 2 changes to 1 files
  bundle2-input-part: total payload size 1686
  bundle2-input-part: "phase-heads" supported
  bundle2-input-part: total payload size 24
  bundle2-input-bundle: 1 parts total
  updating the branch cache
  invalid branchheads cache (served): tip differs
  rebase completed

Test minimization of merge conflicts
  $ hg up -q null
  $ echo a > a
  $ hg add a
  $ hg commit -q -m 'a'
  $ echo b >> a
  $ hg commit -q -m 'ab'
  $ hg bookmark ab
  $ hg up -q '.^'
  $ echo b >> a
  $ echo c >> a
  $ hg commit -q -m 'abc'
  $ hg rebase -s 7bc217434fc1 -d ab --keep
  rebasing 13:7bc217434fc1 "abc" (tip)
  merging a
  warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]
  $ hg diff
  diff -r 328e4ab1f7cc a
  --- a/a	Thu Jan 01 00:00:00 1970 +0000
  +++ b/a	* (glob)
  @@ -1,2 +1,6 @@
   a
   b
  +<<<<<<< dest:   328e4ab1f7cc ab - test: ab
  +=======
  +c
  +>>>>>>> source: 7bc217434fc1 - test: abc
  $ hg rebase --abort
  rebase aborted
  $ hg up -q -C 7bc217434fc1
  $ hg rebase -s . -d ab --keep -t internal:merge3
  rebasing 13:7bc217434fc1 "abc" (tip)
  merging a
  warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]
  $ hg diff
  diff -r 328e4ab1f7cc a
  --- a/a	Thu Jan 01 00:00:00 1970 +0000
  +++ b/a	* (glob)
  @@ -1,2 +1,8 @@
   a
  +<<<<<<< dest:   328e4ab1f7cc ab - test: ab
   b
  +||||||| base
  +=======
  +b
  +c
  +>>>>>>> source: 7bc217434fc1 - test: abc

Test rebase with obsstore turned on and off (issue5606)

  $ cd $TESTTMP
  $ hg init b
  $ cd b
  $ hg debugdrawdag <<'EOS'
  > D
  > |
  > C
  > |
  > B E
  > |/
  > A
  > EOS

  $ hg update E -q
  $ echo 3 > B
  $ hg commit --amend -m E -A B -q
  $ hg rebase -r B+D -d . --config experimental.evolution=true
  rebasing 1:112478962961 "B" (B)
  merging B
  warning: conflicts while merging B! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]

  $ echo 4 > B
  $ hg resolve -m
  (no more unresolved files)
  continue: hg rebase --continue
  $ hg rebase --continue --config experimental.evolution=none
  rebasing 1:112478962961 "B" (B)
  rebasing 3:f585351a92f8 "D" (D)
  warning: orphaned descendants detected, not stripping 112478962961
  saved backup bundle to $TESTTMP/b/.hg/strip-backup/f585351a92f8-e536a9e4-rebase.hg

  $ rm .hg/localtags
  $ hg tglog
  o  5:draft 'D'
  |
  o  4:draft 'B'
  |
  @  3:draft 'E'
  |
  | o  2:draft 'C'
  | |
  | o  1:draft 'B'
  |/
  o  0:draft 'A'