view tests/test-subrepo-svn.t @ 35569:964212780daf

rust: implementation of `hg`

This commit provides a mostly-working implementation of the
`hg` script in Rust along with scaffolding to support Rust in
the repository.

If you are familiar with Rust, the contents of the added rust/
directory should be pretty straightforward. We create an "hgcli"
package that implements a binary application to run Mercurial.
The output of this package is an "hg" binary.

Our Rust `hg` (henceforth "rhg") essentially is a port of the existing
`hg` Python script. The main difference is the creation of the embedded
CPython interpreter is handled by the binary itself instead of relying
on the shebang. In that sense, rhg is more similar to the "exe wrapper"
we currently use on Windows. However, unlike the exe wrapper, rhg does
not call the `hg` Python script. Instead, it uses the CPython APIs to
import mercurial modules and call appropriate functions. The amount of
code here is surprisingly small.

It is my intent to replace the existing C-based exe wrapper with rhg.
Preferably in the next Mercurial release. This should be achievable -
at least for some Mercurial distributions. The future/timeline for
rhg on other platforms is less clear. We already ship a hg.exe on
Windows. So if we get the quirks with Rust worked out, shipping a
Rust-based hg.exe should hopefully not be too contentious.

Now onto the implementation.

We're using python27-sys and the cpython crates for talking to the
CPython API. We currently don't use too much functionality of the
cpython crate and could have probably cut it out. However, it does
provide a reasonable abstraction over unsafe {} CPython function
calls. While we still have our fair share of those, at least we're
not dealing with too much refcounting, error checking, etc. So I
think the use of the cpython crate is justified. Plus, there is
not-yet-implemented functionality that could benefit from cpython. I
see our use of this crate only increasing.

The cpython and python27-sys crates are not without their issues.
The cpython crate didn't seem to account for the embedding use case
in its design. Instead, it seems to assume that you are building
a Python extension. It is making some questionable decisions around
certain CPython APIs. For example, it insists that
PyEval_ThreadsInitialized() is called and that the Python code
likely isn't the main thread in the underlying application. It
is also missing some functionality that is important for embedded
use cases (such as exporting the path to the Python interpreter
from its build script). After spending several hours trying to
wrangle python27-sys and cpython, I gave up and forked the project
on GitHub. Our Cargo.toml tracks this fork. I'm optimistic that
the upstream project will accept our contributions and we can
eventually unfork.

There is a non-trivial amount of code in our custom Cargo build
script. Our build.rs (which is called as part of building the hgcli
crate):

* Validates that the Python interpreter that was detected by the
  python27-sys crate provides a shared library (we only support
  shared library linking at this time - although this restriction
  could be loosened).
* Validates that the Python is built with UCS-4 support. This ensures
  maximum Unicode compatibility.
* Exports variables to the crate build allowing the built crate to e.g.
  find the path to the Python interpreter.

The produced rhg should be considered alpha quality. There are several
known deficiencies. Many of these are documented with inline TODOs.

Probably the biggest limitation of rhg is that it assumes it is
running from the ./rust/target/<target> directory of a source
distribution. So, rhg is currently not very practical for real-world
use. But, if you can `cargo build` it, running the binary *should*
yield a working Mercurial CLI.

In order to support using rhg with the test harness, we needed to hack
up run-tests.py so the path to Mercurial's Python files is set properly.
The change is extremely hacky and is only intended to be a stop-gap
until the test harness gains first-class support for installing rhg.
This will likely occur after we support running rhg outside the
source directory.

Despite its officially alpha quality, rhg copes extremely well with
the test harness (at least on Linux). Using
`run-tests.py --with-hg ../rust/target/debug/hg`, I only encounter
the following failures:

* test-run-tests.t -- Warnings emitted about using an unexpected
  Mercurial library. This is due to the hacky nature of setting the
  Python directory when run-tests.py detected rhg.
* test-devel-warnings.t -- Expected stack trace missing frame for `hg`
  (This is expected since we no longer have an `hg` script!)
* test-convert.t -- Test running `$PYTHON "$BINDIR"/hg`, which obviously
  assumes `hg` is a Python script.
* test-merge-tools.t -- Same assumption about `hg` being executable with
  Python.
* test-http-bad-server.t -- Seeing exit code 255 instead of 1 around
  line 358.
* test-blackbox.t -- Exit code 255 instead of 1.
* test-basic.t -- Exit code 255 instead of 1.

It certainly looks like we have a bug around exit code handling. I
don't think it is severe enough to hold up review and landing of this
initial implementation. Perfect is the enemy of good.

Differential Revision: https://phab.mercurial-scm.org/D1581

#require svn15

  $ SVNREPOPATH=`pwd`/svn-repo
#if windows
  $ SVNREPOURL=file:///`$PYTHON -c "import urllib, sys; sys.stdout.write(urllib.quote(sys.argv[1]))" "$SVNREPOPATH"`
#else
  $ SVNREPOURL=file://`$PYTHON -c "import urllib, sys; sys.stdout.write(urllib.quote(sys.argv[1]))" "$SVNREPOPATH"`
#endif

  $ filter_svn_output () {
  >     egrep -v 'Committing|Transmitting|Updating|(^$)' || true
  > }

create subversion repo

  $ WCROOT="`pwd`/svn-wc"
  $ svnadmin create svn-repo
  $ svn co "$SVNREPOURL" svn-wc
  Checked out revision 0.
  $ cd svn-wc
  $ mkdir src
  $ echo alpha > src/alpha
  $ svn add src
  A         src
  A         src/alpha
  $ mkdir externals
  $ echo other > externals/other
  $ svn add externals
  A         externals
  A         externals/other
  $ svn ci -qm 'Add alpha'
  $ svn up -q
  $ echo "externals -r1 $SVNREPOURL/externals" > extdef
  $ svn propset -F extdef svn:externals src
  property 'svn:externals' set on 'src'
  $ svn ci -qm 'Setting externals'
  $ cd ..

create hg repo

  $ mkdir sub
  $ cd sub
  $ hg init t
  $ cd t

first revision, no sub

  $ echo a > a
  $ hg ci -Am0
  adding a

add first svn sub with leading whitespaces

  $ echo "s =        [svn]       $SVNREPOURL/src" >> .hgsub
  $ echo "subdir/s = [svn]       $SVNREPOURL/src" >> .hgsub
  $ svn co --quiet "$SVNREPOURL"/src s
  $ mkdir subdir
  $ svn co --quiet "$SVNREPOURL"/src subdir/s
  $ hg add .hgsub

svn subrepo is disabled by default

  $ hg ci -m1
  abort: svn subrepos not allowed
  (see 'hg help config.subrepos' for details)
  [255]

so enable it

  $ cat >> $HGRCPATH <<EOF
  > [subrepos]
  > svn:allowed = true
  > EOF

  $ hg ci -m1

make sure we avoid empty commits (issue2445)

  $ hg sum
  parent: 1:* tip (glob)
   1
  branch: default
  commit: (clean)
  update: (current)
  phases: 2 draft
  $ hg ci -moops
  nothing changed
  [1]

debugsub

  $ hg debugsub
  path s
   source   file:/*/$TESTTMP/svn-repo/src (glob)
   revision 2
  path subdir/s
   source   file:/*/$TESTTMP/svn-repo/src (glob)
   revision 2

change file in svn and hg, commit

  $ echo a >> a
  $ echo alpha >> s/alpha
  $ hg sum
  parent: 1:* tip (glob)
   1
  branch: default
  commit: 1 modified, 1 subrepos
  update: (current)
  phases: 2 draft
  $ hg commit --subrepos -m 'Message!' | filter_svn_output
  committing subrepository s
  Sending*s/alpha (glob)
  Committed revision 3.
  Fetching external item into '*s/externals'* (glob)
  External at revision 1.
  At revision 3.
  $ hg debugsub
  path s
   source   file:/*/$TESTTMP/svn-repo/src (glob)
   revision 3
  path subdir/s
   source   file:/*/$TESTTMP/svn-repo/src (glob)
   revision 2

missing svn file, commit should fail

  $ rm s/alpha
  $ hg commit --subrepos -m 'abort on missing file'
  committing subrepository s
  abort: cannot commit missing svn entries (in subrepository "s")
  [255]
  $ svn revert s/alpha > /dev/null

add an unrelated revision in svn and update the subrepo to without
bringing any changes.

  $ svn mkdir "$SVNREPOURL/unrelated" -qm 'create unrelated'
  $ svn up -q s
  $ hg sum
  parent: 2:* tip (glob)
   Message!
  branch: default
  commit: (clean)
  update: (current)
  phases: 3 draft

  $ echo a > s/a

should be empty despite change to s/a

  $ hg st

add a commit from svn

  $ cd "$WCROOT/src"
  $ svn up -q
  $ echo xyz >> alpha
  $ svn propset svn:mime-type 'text/xml' alpha
  property 'svn:mime-type' set on 'alpha'
  $ svn ci -qm 'amend a from svn'
  $ cd ../../sub/t

this commit from hg will fail

  $ echo zzz >> s/alpha
  $ (hg ci --subrepos -m 'amend alpha from hg' 2>&1; echo "[$?]") | grep -vi 'out of date'
  committing subrepository s
  abort: svn:*Commit failed (details follow): (glob)
  [255]
  $ svn revert -q s/alpha

this commit fails because of meta changes

  $ svn propset svn:mime-type 'text/html' s/alpha
  property 'svn:mime-type' set on 's/alpha'
  $ (hg ci --subrepos -m 'amend alpha from hg' 2>&1; echo "[$?]") | grep -vi 'out of date'
  committing subrepository s
  abort: svn:*Commit failed (details follow): (glob)
  [255]
  $ svn revert -q s/alpha

this commit fails because of externals changes

  $ echo zzz > s/externals/other
  $ hg ci --subrepos -m 'amend externals from hg'
  committing subrepository s
  abort: cannot commit svn externals (in subrepository "s")
  [255]
  $ hg diff --subrepos -r 1:2 | grep -v diff
  --- a/.hgsubstate	Thu Jan 01 00:00:00 1970 +0000
  +++ b/.hgsubstate	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,2 +1,2 @@
  -2 s
  +3 s
   2 subdir/s
  --- a/a	Thu Jan 01 00:00:00 1970 +0000
  +++ b/a	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +1,2 @@
   a
  +a
  $ svn revert -q s/externals/other

this commit fails because of externals meta changes

  $ svn propset svn:mime-type 'text/html' s/externals/other
  property 'svn:mime-type' set on 's/externals/other'
  $ hg ci --subrepos -m 'amend externals from hg'
  committing subrepository s
  abort: cannot commit svn externals (in subrepository "s")
  [255]
  $ svn revert -q s/externals/other

clone

  $ cd ..
  $ hg clone t tc
  updating to branch default
  A    tc/s/alpha
   U   tc/s
  
  Fetching external item into 'tc/s/externals'* (glob)
  A    tc/s/externals/other
  Checked out external at revision 1.
  
  Checked out revision 3.
  A    tc/subdir/s/alpha
   U   tc/subdir/s
  
  Fetching external item into 'tc/subdir/s/externals'* (glob)
  A    tc/subdir/s/externals/other
  Checked out external at revision 1.
  
  Checked out revision 2.
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd tc

debugsub in clone

  $ hg debugsub
  path s
   source   file:/*/$TESTTMP/svn-repo/src (glob)
   revision 3
  path subdir/s
   source   file:/*/$TESTTMP/svn-repo/src (glob)
   revision 2

verify subrepo is contained within the repo directory

  $ $PYTHON -c "import os.path; print os.path.exists('s')"
  True

update to nullrev (must delete the subrepo)

  $ hg up null
  0 files updated, 0 files merged, 3 files removed, 0 files unresolved
  $ ls

Check hg update --clean
  $ cd "$TESTTMP/sub/t"
  $ cd s
  $ echo c0 > alpha
  $ echo c1 > f1
  $ echo c1 > f2
  $ svn add f1 -q
  $ svn status | sort
  
  ? *    a (glob)
  ? *    f2 (glob)
  A *    f1 (glob)
  M *    alpha (glob)
  Performing status on external item at 'externals'* (glob)
  X *    externals (glob)
  $ cd ../..
  $ hg -R t update -C
  
  Fetching external item into 't/s/externals'* (glob)
  Checked out external at revision 1.
  
  Checked out revision 3.
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd t/s
  $ svn status | sort
  
  ? *    a (glob)
  ? *    f1 (glob)
  ? *    f2 (glob)
  Performing status on external item at 'externals'* (glob)
  X *    externals (glob)

Sticky subrepositories, no changes
  $ cd "$TESTTMP/sub/t"
  $ hg id -n
  2
  $ cd s
  $ svnversion
  3
  $ cd ..
  $ hg update 1
  U    *s/alpha (glob)
  
  Fetching external item into '*s/externals'* (glob)
  Checked out external at revision 1.
  
  Checked out revision 2.
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg id -n
  1
  $ cd s
  $ svnversion
  2
  $ cd ..

Sticky subrepositories, file changes
  $ touch s/f1
  $ cd s
  $ svn add f1
  A         f1
  $ cd ..
  $ hg id -n
  1+
  $ cd s
  $ svnversion
  2M
  $ cd ..
  $ hg update tip
   subrepository s diverged (local revision: 2, remote revision: 3)
  (M)erge, keep (l)ocal [working copy] or keep (r)emote [destination]? m
   subrepository sources for s differ
  use (l)ocal source (2) or (r)emote source (3)? l
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg id -n
  2+
  $ cd s
  $ svnversion
  2M
  $ cd ..
  $ hg update --clean tip
  U    *s/alpha (glob)
  
  Fetching external item into '*s/externals'* (glob)
  Checked out external at revision 1.
  
  Checked out revision 3.
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

Sticky subrepository, revision updates
  $ hg id -n
  2
  $ cd s
  $ svnversion
  3
  $ cd ..
  $ cd s
  $ svn update -qr 1
  $ cd ..
  $ hg update 1
   subrepository s diverged (local revision: 3, remote revision: 2)
  (M)erge, keep (l)ocal [working copy] or keep (r)emote [destination]? m
   subrepository sources for s differ (in checked out version)
  use (l)ocal source (1) or (r)emote source (2)? l
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg id -n
  1+
  $ cd s
  $ svnversion
  1
  $ cd ..

Sticky subrepository, file changes and revision updates
  $ touch s/f1
  $ cd s
  $ svn add f1
  A         f1
  $ svnversion
  1M
  $ cd ..
  $ hg id -n
  1+
  $ hg update tip
   subrepository s diverged (local revision: 3, remote revision: 3)
  (M)erge, keep (l)ocal [working copy] or keep (r)emote [destination]? m
   subrepository sources for s differ
  use (l)ocal source (1) or (r)emote source (3)? l
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg id -n
  2+
  $ cd s
  $ svnversion
  1M
  $ cd ..

Sticky repository, update --clean
  $ hg update --clean tip | grep -v 's[/\]externals[/\]other'
  U    *s/alpha (glob)
   U   *s (glob)
  
  Fetching external item into '*s/externals'* (glob)
  Checked out external at revision 1.
  
  Checked out revision 3.
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg id -n
  2
  $ cd s
  $ svnversion
  3
  $ cd ..

Test subrepo already at intended revision:
  $ cd s
  $ svn update -qr 2
  $ cd ..
  $ hg update 1
   subrepository s diverged (local revision: 3, remote revision: 2)
  (M)erge, keep (l)ocal [working copy] or keep (r)emote [destination]? m
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg id -n
  1+
  $ cd s
  $ svnversion
  2
  $ cd ..

Test case where subversion would fail to update the subrepo because there
are unknown directories being replaced by tracked ones (happens with rebase).

  $ cd "$WCROOT/src"
  $ mkdir dir
  $ echo epsilon.py > dir/epsilon.py
  $ svn add dir
  A         dir
  A         dir/epsilon.py
  $ svn ci -qm 'Add dir/epsilon.py'
  $ cd ../..
  $ hg init rebaserepo
  $ cd rebaserepo
  $ svn co -r5 --quiet "$SVNREPOURL"/src s
  $ echo "s =        [svn]       $SVNREPOURL/src" >> .hgsub
  $ hg add .hgsub
  $ hg ci -m addsub
  $ echo a > a
  $ hg add .
  adding a
  $ hg ci -m adda
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ svn up -qr6 s
  $ hg ci -m updatesub
  created new head
  $ echo pyc > s/dir/epsilon.pyc
  $ hg up 1
  D    *s/dir (glob)
  
  Fetching external item into '*s/externals'* (glob)
  Checked out external at revision 1.
  
  Checked out revision 5.
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg up -q 2

Modify one of the externals to point to a different path so we can
test having obstructions when switching branches on checkout:
  $ hg checkout tip
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo "obstruct =        [svn]       $SVNREPOURL/externals" >> .hgsub
  $ svn co -r5 --quiet "$SVNREPOURL"/externals obstruct
  $ hg commit -m 'Start making obstructed working copy'
  $ hg book other
  $ hg co -r 'p1(tip)'
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (leaving bookmark other)
  $ echo "obstruct =        [svn]       $SVNREPOURL/src" >> .hgsub
  $ svn co -r5 --quiet "$SVNREPOURL"/src obstruct
  $ hg commit -m 'Other branch which will be obstructed'
  created new head

Switching back to the head where we have another path mapped to the
same subrepo should work if the subrepo is clean.
  $ hg co other
  A    *obstruct/other (glob)
  Checked out revision 1.
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (activating bookmark other)

This is surprising, but is also correct based on the current code:
  $ echo "updating should (maybe) fail" > obstruct/other
  $ hg co tip
  abort: uncommitted changes
  (commit or update --clean to discard changes)
  [255]

Point to a Subversion branch which has since been deleted and recreated
First, create that condition in the repository.

  $ hg ci --subrepos -m cleanup | filter_svn_output
  committing subrepository obstruct
  Sending        obstruct/other
  Committed revision 7.
  At revision 7.
  $ svn mkdir -qm "baseline" $SVNREPOURL/trunk
  $ svn copy -qm "initial branch" $SVNREPOURL/trunk $SVNREPOURL/branch
  $ svn co --quiet "$SVNREPOURL"/branch tempwc
  $ cd tempwc
  $ echo "something old" > somethingold
  $ svn add somethingold
  A         somethingold
  $ svn ci -qm 'Something old'
  $ svn rm -qm "remove branch" $SVNREPOURL/branch
  $ svn copy -qm "recreate branch" $SVNREPOURL/trunk $SVNREPOURL/branch
  $ svn up -q
  $ echo "something new" > somethingnew
  $ svn add somethingnew
  A         somethingnew
  $ svn ci -qm 'Something new'
  $ cd ..
  $ rm -rf tempwc
  $ svn co "$SVNREPOURL/branch"@10 recreated
  A    recreated/somethingold
  Checked out revision 10.
  $ echo "recreated =        [svn]       $SVNREPOURL/branch" >> .hgsub
  $ hg ci -m addsub
  $ cd recreated
  $ svn up -q
  $ cd ..
  $ hg ci -m updatesub
  $ hg up -r-2
  D    *recreated/somethingnew (glob)
  A    *recreated/somethingold (glob)
  Checked out revision 10.
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (leaving bookmark other)
  $ test -f recreated/somethingold

Test archive

  $ hg archive -S ../archive-all --debug --config progress.debug=true
  archiving: 0/2 files (0.00%)
  archiving: .hgsub 1/2 files (50.00%)
  archiving: .hgsubstate 2/2 files (100.00%)
  archiving (obstruct): 0/1 files (0.00%)
  archiving (obstruct): 1/1 files (100.00%)
  archiving (recreated): 0/1 files (0.00%)
  archiving (recreated): 1/1 files (100.00%)
  archiving (s): 0/2 files (0.00%)
  archiving (s): 1/2 files (50.00%)
  archiving (s): 2/2 files (100.00%)

  $ hg archive -S ../archive-exclude --debug --config progress.debug=true -X **old
  archiving: 0/2 files (0.00%)
  archiving: .hgsub 1/2 files (50.00%)
  archiving: .hgsubstate 2/2 files (100.00%)
  archiving (obstruct): 0/1 files (0.00%)
  archiving (obstruct): 1/1 files (100.00%)
  archiving (recreated): 0 files
  archiving (s): 0/2 files (0.00%)
  archiving (s): 1/2 files (50.00%)
  archiving (s): 2/2 files (100.00%)
  $ find ../archive-exclude | sort
  ../archive-exclude
  ../archive-exclude/.hg_archival.txt
  ../archive-exclude/.hgsub
  ../archive-exclude/.hgsubstate
  ../archive-exclude/obstruct
  ../archive-exclude/obstruct/other
  ../archive-exclude/s
  ../archive-exclude/s/alpha
  ../archive-exclude/s/dir
  ../archive-exclude/s/dir/epsilon.py

Test forgetting files, not implemented in svn subrepo, used to
traceback

  $ hg forget 'notafile*'
  notafile*: $ENOENT$
  [1]

Test a subrepo referencing a just moved svn path. Last commit rev will
be different from the revision, and the path will be different as
well.

  $ cd "$WCROOT"
  $ svn up > /dev/null
  $ mkdir trunk/subdir branches
  $ echo a > trunk/subdir/a
  $ svn add trunk/subdir branches
  A         trunk/subdir
  A         trunk/subdir/a
  A         branches
  $ svn ci -qm addsubdir
  $ svn cp -qm branchtrunk $SVNREPOURL/trunk $SVNREPOURL/branches/somebranch
  $ cd ..

  $ hg init repo2
  $ cd repo2
  $ svn co $SVNREPOURL/branches/somebranch/subdir
  A    subdir/a
  Checked out revision 15.
  $ echo "subdir = [svn] $SVNREPOURL/branches/somebranch/subdir" > .hgsub
  $ hg add .hgsub
  $ hg ci -m addsub
  $ hg up null
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ hg up
  A    *subdir/a (glob)
  Checked out revision 15.
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd ..

Test sanitizing ".hg/hgrc" in subrepo

  $ cd sub/t
  $ hg update -q -C tip
  $ cd s
  $ mkdir .hg
  $ echo '.hg/hgrc in svn repo' > .hg/hgrc
  $ mkdir -p sub/.hg
  $ echo 'sub/.hg/hgrc in svn repo' > sub/.hg/hgrc
  $ svn add .hg sub
  A         .hg
  A         .hg/hgrc
  A         sub
  A         sub/.hg
  A         sub/.hg/hgrc
  $ svn ci -qm 'add .hg/hgrc to be sanitized at hg update'
  $ svn up -q
  $ cd ..
  $ hg commit -S -m 'commit with svn revision including .hg/hgrc'
  $ grep ' s$' .hgsubstate
  16 s
  $ cd ..

  $ hg -R tc pull -u -q 2>&1 | sort
  warning: removing potentially hostile 'hgrc' in '$TESTTMP/sub/tc/s/.hg'
  warning: removing potentially hostile 'hgrc' in '$TESTTMP/sub/tc/s/sub/.hg'
  $ cd tc
  $ grep ' s$' .hgsubstate
  16 s
  $ test -f s/.hg/hgrc
  [1]
  $ test -f s/sub/.hg/hgrc
  [1]

Test that sanitizing is omitted in meta data area:

  $ mkdir s/.svn/.hg
  $ echo '.hg/hgrc in svn metadata area' > s/.svn/.hg/hgrc
  $ hg update -q -C '.^1'

  $ cd ../..

SEC: test for ssh exploit

  $ hg init ssh-vuln
  $ cd ssh-vuln
  $ echo "s = [svn]$SVNREPOURL/src" >> .hgsub
  $ svn co --quiet "$SVNREPOURL"/src s
  $ hg add .hgsub
  $ hg ci -m1
  $ echo "s = [svn]svn+ssh://-oProxyCommand=touch%20owned%20nested" > .hgsub
  $ hg ci -m2
  $ cd ..
  $ hg clone ssh-vuln ssh-vuln-clone
  updating to branch default
  abort: potentially unsafe url: 'svn+ssh://-oProxyCommand=touch owned nested' (in subrepository "s")
  [255]

also check that a percent encoded '-' (%2D) doesn't work

  $ cd ssh-vuln
  $ echo "s = [svn]svn+ssh://%2DoProxyCommand=touch%20owned%20nested" > .hgsub
  $ hg ci -m3
  $ cd ..
  $ rm -r ssh-vuln-clone
  $ hg clone ssh-vuln ssh-vuln-clone
  updating to branch default
  abort: potentially unsafe url: 'svn+ssh://-oProxyCommand=touch owned nested' (in subrepository "s")
  [255]

also check that hiding the attack in the username doesn't work:

  $ cd ssh-vuln
  $ echo "s = [svn]svn+ssh://%2DoProxyCommand=[e-mail]/nested" > .hgsub
  $ hg ci -m3
  $ cd ..
  $ rm -r ssh-vuln-clone
  $ hg clone ssh-vuln ssh-vuln-clone
  updating to branch default
  abort: potentially unsafe url: 'svn+ssh://-oProxyCommand=touch owned [e-mail]/nested' (in subrepository "s")
  [255]