view tests/test-issue3084.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

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "largefiles =" >> $HGRCPATH

Create the repository outside $HOME since largefiles write to
$HOME/.cache/largefiles.

  $ hg init test
  $ cd test
  $ echo "root" > root
  $ hg add root
  $ hg commit -m "Root commit" --config extensions.largefiles=!

Ensure that .hg/largefiles isn't created before largefiles are added
#if unix-permissions
  $ chmod 555 .hg
#endif
  $ hg status
#if unix-permissions
  $ chmod 755 .hg
#endif

  $ test -f .hg/largefiles
  [1]

  $ echo "large" > foo
  $ hg add --large foo
  $ hg commit -m "Add foo as a largefile"

  $ hg update -r 0
  getting changed largefiles
  0 largefiles updated, 1 removed
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo "normal" > foo
  $ hg add foo
  $ hg commit -m "Add foo as normal file"
  created new head

Normal file in the working copy, keeping the normal version:

  $ echo "n" | hg merge --config ui.interactive=Yes
  remote turned local normal file foo into a largefile
  use (l)argefile or keep (n)ormal file? n
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg status
  $ cat foo
  normal

Normal file in the working copy, keeping the largefile version:

  $ hg update -q -C
  $ echo "l" | hg merge --config ui.interactive=Yes
  remote turned local normal file foo into a largefile
  use (l)argefile or keep (n)ormal file? l
  getting changed largefiles
  1 largefiles updated, 0 removed
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg status
  M foo

  $ hg diff --nodates
  diff -r fa129ab6b5a7 .hglf/foo
  --- /dev/null
  +++ b/.hglf/foo
  @@ -0,0 +1,1 @@
  +7f7097b041ccf68cc5561e9600da4655d21c6d18
  diff -r fa129ab6b5a7 foo
  --- a/foo
  +++ /dev/null
  @@ -1,1 +0,0 @@
  -normal

  $ cat foo
  large

Largefile in the working copy, keeping the normal version:

  $ hg update -q -C -r 1
  $ echo "n" | hg merge --config ui.interactive=Yes
  remote turned local largefile foo into a normal file
  keep (l)argefile or use (n)ormal file? n
  getting changed largefiles
  0 largefiles updated, 0 removed
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg status
  M foo

  $ hg diff --nodates
  diff -r ff521236428a .hglf/foo
  --- a/.hglf/foo
  +++ /dev/null
  @@ -1,1 +0,0 @@
  -7f7097b041ccf68cc5561e9600da4655d21c6d18
  diff -r ff521236428a foo
  --- /dev/null
  +++ b/foo
  @@ -0,0 +1,1 @@
  +normal

  $ cat foo
  normal

Largefile in the working copy, keeping the largefile version:

  $ hg update -q -C -r 1
  $ echo "l" | hg merge --config ui.interactive=Yes
  remote turned local largefile foo into a normal file
  keep (l)argefile or use (n)ormal file? l
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg status

  $ cat foo
  large

Whatever ... commit something so we can invoke merge when updating

  $ hg commit -m '3: Merge'

Updating from largefile to normal - no reason to prompt

  $ hg up -r 2
  getting changed largefiles
  0 largefiles updated, 0 removed
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ cat foo
  normal

(the update above used to leave the working dir in a very weird state - clean it
  $ hg up -qr null
  $ hg up -qr 2
)

Updating from normal to largefile - no reason to prompt

  $ hg up -r 3
  getting changed largefiles
  1 largefiles updated, 0 removed
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ cat foo
  large

  $ cd ..


Systematic testing of merges involving largefiles:

Ancestor: normal  Parent: normal-id  Parent: large   result: large
Ancestor: normal  Parent: normal2    Parent: large   result: ?
Ancestor: large   Parent: large-id   Parent: normal  result: normal
Ancestor: large   Parent: large2     Parent: normal  result: ?

All cases should try merging both ways.

Prepare test repo:

  $ hg init merges
  $ cd merges

prepare cases with "normal" ancestor:

  $ hg up -qr null
  $ echo normal > f
  $ hg ci -Aqm "normal-ancestor"
  $ hg tag -l "normal-ancestor"
  $ touch f2
  $ hg ci -Aqm "normal-id"
  $ hg tag -l "normal-id"
  $ echo normal2 > f
  $ hg ci -m "normal2"
  $ hg tag -l "normal2"
  $ echo normal > f
  $ hg ci -Aqm "normal-same"
  $ hg tag -l "normal-same"
  $ hg up -qr "normal-ancestor"
  $ hg rm f
  $ echo large > f
  $ hg add --large f
  $ hg ci -qm "large"
  $ hg tag -l "large"

prepare cases with "large" ancestor:

  $ hg up -qr null
  $ echo large > f
  $ hg add --large f
  $ hg ci -qm "large-ancestor"
  $ hg tag -l "large-ancestor"
  $ touch f2
  $ hg ci -Aqm "large-id"
  $ hg tag -l "large-id"
  $ echo large2 > f
  $ hg ci -m "large2"
  $ hg tag -l "large2"
  $ echo large > f
  $ hg ci -Aqm "large-same"
  $ hg tag -l "large-same"
  $ hg up -qr "large-ancestor"
  $ hg rm f
  $ echo normal > f
  $ hg ci -qAm "normal"
  $ hg tag -l "normal"

  $ hg log -GT '{tags}'
  @  normal tip
  |
  | o  large-same
  | |
  | o  large2
  | |
  | o  large-id
  |/
  o  large-ancestor
  
  o  large
  |
  | o  normal-same
  | |
  | o  normal2
  | |
  | o  normal-id
  |/
  o  normal-ancestor
  


Ancestor: normal  Parent: normal-id  Parent: large   result: large

  $ hg up -Cqr normal-id
  $ hg merge -r large
  getting changed largefiles
  1 largefiles updated, 0 removed
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat f
  large

swap

  $ hg up -Cqr large
  $ hg merge -r normal-id
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat f
  large

Ancestor: normal  Parent: normal-same  Parent: large   result: large

  $ hg up -Cqr normal-same
  $ hg merge -r large
  getting changed largefiles
  1 largefiles updated, 0 removed
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat f
  large

swap

  $ hg up -Cqr large
  $ hg merge -r normal-same
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat f
  large

Ancestor: normal  Parent: normal2  Parent: large   result: ?
(annoying extra prompt ... but it do not do any serious harm)

  $ hg up -Cqr normal2
  $ hg merge -r large
  remote turned local normal file f into a largefile
  use (l)argefile or keep (n)ormal file? l
  getting changed largefiles
  1 largefiles updated, 0 removed
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat f
  large

  $ hg up -Cqr normal2
  $ echo n | hg merge -r large --config ui.interactive=Yes
  remote turned local normal file f into a largefile
  use (l)argefile or keep (n)ormal file? n
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat f
  normal2

swap

  $ hg up -Cqr large
  $ hg merge -r normal2
  remote turned local largefile f into a normal file
  keep (l)argefile or use (n)ormal file? l
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat f
  large

  $ hg up -Cqr large
  $ echo n | hg merge -r normal2 --config ui.interactive=Yes
  remote turned local largefile f into a normal file
  keep (l)argefile or use (n)ormal file? n
  getting changed largefiles
  0 largefiles updated, 0 removed
  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat f
  normal2

Ancestor: large   Parent: large-id   Parent: normal  result: normal

  $ hg up -Cqr large-id
  $ hg merge -r normal
  getting changed largefiles
  0 largefiles updated, 0 removed
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat f
  normal

swap

  $ hg up -Cqr normal
  $ hg merge -r large-id
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat f
  normal

Ancestor: large   Parent: large-same   Parent: normal  result: normal

  $ hg up -Cqr large-same
  $ hg merge -r normal
  getting changed largefiles
  0 largefiles updated, 0 removed
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat f
  normal

swap

  $ hg up -Cqr normal
  $ hg merge -r large-same
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat f
  normal

Ancestor: large   Parent: large2   Parent: normal  result: ?
(annoying extra prompt ... but it do not do any serious harm)

  $ hg up -Cqr large2
  $ hg merge -r normal
  remote turned local largefile f into a normal file
  keep (l)argefile or use (n)ormal file? l
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat f
  large2

  $ hg up -Cqr large2
  $ echo n | hg merge -r normal --config ui.interactive=Yes
  remote turned local largefile f into a normal file
  keep (l)argefile or use (n)ormal file? n
  getting changed largefiles
  0 largefiles updated, 0 removed
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat f
  normal

swap

  $ hg up -Cqr normal
  $ hg merge -r large2
  remote turned local normal file f into a largefile
  use (l)argefile or keep (n)ormal file? l
  getting changed largefiles
  1 largefiles updated, 0 removed
  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat f
  large2

  $ hg up -Cqr normal
  $ echo n | hg merge -r large2 --config ui.interactive=Yes
  remote turned local normal file f into a largefile
  use (l)argefile or keep (n)ormal file? n
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat f
  normal

  $ cd ..