view tests/test-bheads.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

  $ heads()
  > {
  >    hg heads --template '{rev}: {desc|firstline|strip} ({branches})\n' "$@"
  > }

  $ hg init a
  $ cd a
  $ echo 'root' >root
  $ hg add root
  $ hg commit -m "Adding root node"
  $ heads
  0: Adding root node ()
-------
  $ heads .
  0: Adding root node ()

=======

  $ echo 'a' >a
  $ hg add a
  $ hg branch a
  marked working directory as branch a
  (branches are permanent and global, did you want a bookmark?)
  $ hg commit -m "Adding a branch"
  $ heads
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  1: Adding a branch (a)

=======

  $ hg update -C 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo 'b' >b
  $ hg add b
  $ hg branch b
  marked working directory as branch b
  $ hg commit -m "Adding b branch"
  $ heads
  2: Adding b branch (b)
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  2: Adding b branch (b)

=======

  $ echo 'bh1' >bh1
  $ hg add bh1
  $ hg commit -m "Adding b branch head 1"
  $ heads
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  3: Adding b branch head 1 (b)

=======

  $ hg update -C 2
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo 'bh2' >bh2
  $ hg add bh2
  $ hg commit -m "Adding b branch head 2"
  created new head
  $ heads
  4: Adding b branch head 2 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  $ heads .
  4: Adding b branch head 2 (b)
  3: Adding b branch head 1 (b)

=======

  $ hg update -C 2
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo 'bh3' >bh3
  $ hg add bh3
  $ hg commit -m "Adding b branch head 3"
  created new head
  $ heads
  5: Adding b branch head 3 (b)
  4: Adding b branch head 2 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  5: Adding b branch head 3 (b)
  4: Adding b branch head 2 (b)
  3: Adding b branch head 1 (b)

=======

  $ hg merge 4
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg commit -m "Merging b branch head 2 and b branch head 3"
  $ heads
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)

=======

  $ echo 'c' >c
  $ hg add c
  $ hg branch c
  marked working directory as branch c
  $ hg commit -m "Adding c branch"
  $ heads
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  7: Adding c branch (c)

=======

  $ heads -r 3 .
  no open branch heads found on branches c (started at 3)
  [1]
  $ heads -r 2 .
  7: Adding c branch (c)
-------
  $ hg update -C 4
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
-------
  $ heads -r 3 .
  3: Adding b branch head 1 (b)
-------
  $ heads -r 2 .
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
-------
  $ heads -r 7 .
  no open branch heads found on branches b (started at 7)
  [1]

=======

  $ for i in 0 1 2 3 4 5 6 7; do
  >     hg update -C "$i"
  >     heads
  >     echo '-------'
  >     heads .
  >     echo '-------'
  > done
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  0: Adding root node ()
  -------
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  1: Adding a branch (a)
  -------
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  7: Adding c branch (c)
  -------

=======

  $ for i in a b c z; do
  >     heads "$i"
  >     echo '-------'
  > done
  1: Adding a branch (a)
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  7: Adding c branch (c)
  -------
  abort: unknown revision 'z'!
  -------

=======

  $ heads 0 1 2 3 4 5 6 7
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()

Topological heads:

  $ heads -t
  7: Adding c branch (c)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)

  $ cd ..
______________

"created new head" message tests

  $ hg init newheadmsg
  $ cd newheadmsg

Init: no msg

  $ echo 1 > a
  $ hg ci -Am "a0: Initial root"
  adding a
  $ echo 2 >> a
  $ hg ci -m "a1 (HN)"

  $ hg branch b
  marked working directory as branch b
  (branches are permanent and global, did you want a bookmark?)
  $ echo 1 > b
  $ hg ci -Am "b2: Initial root for branch b"
  adding b
  $ echo 2 >> b
  $ hg ci -m "b3 (HN)"

Case NN: msg

  $ hg up -q null
  $ hg branch -f b
  marked working directory as branch b
  $ echo 1 > bb
  $ hg ci -Am "b4 (NN): new topo root for branch b"
  adding bb
  created new head

Case HN: no msg

  $ echo 2 >> bb
  $ hg ci -m "b5 (HN)"

Case BN: msg

  $ hg branch -f default
  marked working directory as branch default
  $ echo 1 > aa
  $ hg ci -Am "a6 (BN): new branch root"
  adding aa
  created new head

Case CN: msg

  $ hg up -q 4
  $ echo 3 >> bbb
  $ hg ci -Am "b7 (CN): regular new head"
  adding bbb
  created new head

Case BB: msg

  $ hg up -q 4
  $ hg merge -q 3
  $ hg branch -f default
  marked working directory as branch default
  $ hg ci -m "a8 (BB): weird new branch root"
  created new head

Case CB: msg

  $ hg up -q 4
  $ hg merge -q 1
  $ hg ci -m "b9 (CB): new head from branch merge"
  created new head

Case HB: no msg

  $ hg up -q 7
  $ hg merge -q 6
  $ hg ci -m "b10 (HB): continuing head from branch merge"

Case CC: msg

  $ hg up -q 4
  $ hg merge -q 2
  $ hg ci -m "b11 (CC): new head from merge"
  created new head

Case CH: no msg

  $ hg up -q 2
  $ hg merge -q 10
  $ hg ci -m "b12 (CH): continuing head from merge"

Case HH: no msg

  $ hg merge -q 3
  $ hg ci -m "b12 (HH): merging two heads"

  $ cd ..