hg debuginstall
  $ hg debuginstall
  checking encoding (ascii)...
  checking Python executable (*) (glob)
  checking Python implementation (*) (glob)
  checking Python version (2.*) (glob) (no-py3 !)
  checking Python version (3.*) (glob) (py3 !)
  checking Python lib (.*[Ll]ib.*)... (re)
  checking Python security support (*) (glob)
    TLS 1.2 not supported by Python install; network connections lack modern security (?)
    SNI not supported by Python install; may have connectivity issues with some servers (?)
  checking Rust extensions \((installed|missing)\) (re)
  checking Mercurial version (*) (glob)
  checking Mercurial custom build (*) (glob)
  checking module policy (*) (glob)
  checking installed modules (*mercurial)... (glob)
  checking registered compression engines (*zlib*) (glob)
  checking available compression engines (*zlib*) (glob)
  checking available compression engines for wire protocol (*zlib*) (glob)
  checking "re2" regexp engine \((available|missing)\) (re)
  checking "re2" regexp engine Rust bindings \((installed|missing)\) (re) (rust !)
  checking templates (*mercurial?templates)... (glob)
  checking default template (*mercurial?templates?map-cmdline.default) (glob)
  checking commit editor... (*) (glob)
  checking username (test)
  no problems detected

hg debuginstall JSON
  $ hg debuginstall -Tjson | sed 's|\\\\|\\|g'
  [
   {
    "compengines": ["bz2", "bz2truncated", "none", "zlib"*], (glob)
    "compenginesavail": ["bz2", "bz2truncated", "none", "zlib"*], (glob)
    "compenginesserver": [*"zlib"*], (glob)
    "defaulttemplate": "*mercurial?templates?map-cmdline.default", (glob)
    "defaulttemplateerror": null,
    "defaulttemplatenotfound": "default",
    "editor": "*", (glob)
    "editornotfound": false,
    "encoding": "ascii",
    "encodingerror": null,
    "extensionserror": null, (no-pure !)
    "hgmodulepolicy": "*", (glob)
    "hgmodules": "*mercurial", (glob)
    "hgver": "*", (glob)
    "hgverextra": "*", (glob)
    "problems": 0,
    "pythonexe": "*", (glob)
    "pythonimplementation": "*", (glob)
    "pythonlib": "*", (glob)
    "pythonsecurity": [*], (glob)
    "pythonver": "*.*.*", (glob)
    "re2": (true|false), (re)
    "templatedirs": "*mercurial?templates", (glob)
    "username": "test",
    "usernameerror": null,
    "vinotfound": false
   }
  ]

hg debuginstall with no username
  $ HGUSER= hg debuginstall
  checking encoding (ascii)...
  checking Python executable (*) (glob)
  checking Python implementation (*) (glob)
  checking Python version (2.*) (glob) (no-py3 !)
  checking Python version (3.*) (glob) (py3 !)
  checking Python lib (.*[Ll]ib.*)... (re)
  checking Python security support (*) (glob)
    TLS 1.2 not supported by Python install; network connections lack modern security (?)
    SNI not supported by Python install; may have connectivity issues with some servers (?)
  checking Rust extensions \((installed|missing)\) (re)
  checking Mercurial version (*) (glob)
  checking Mercurial custom build (*) (glob)
  checking module policy (*) (glob)
  checking installed modules (*mercurial)... (glob)
  checking registered compression engines (*zlib*) (glob)
  checking available compression engines (*zlib*) (glob)
  checking available compression engines for wire protocol (*zlib*) (glob)
  checking "re2" regexp engine \((available|missing)\) (re)
  checking "re2" regexp engine Rust bindings \((installed|missing)\) (re) (rust !)
  checking templates (*mercurial?templates)... (glob)
  checking default template (*mercurial?templates?map-cmdline.default) (glob)
  checking commit editor... (*) (glob)
  checking username...
   no username supplied
   (specify a username in your configuration file)
  1 problems detected, please check your install!
  [1]

hg debuginstall with invalid encoding
  $ HGENCODING=invalidenc hg debuginstall | grep encoding
  checking encoding (invalidenc)...
   unknown encoding: invalidenc

exception message in JSON

  $ HGENCODING=invalidenc HGUSER= hg debuginstall -Tjson | grep error
    "defaulttemplateerror": null,
    "encodingerror": "unknown encoding: invalidenc",
    "extensionserror": null, (no-pure !)
    "usernameerror": "no username supplied",

path variables are expanded (~ is the same as $TESTTMP)
  $ mkdir tools
  $ touch tools/testeditor.exe
#if execbit
  $ chmod 755 tools/testeditor.exe
#endif
  $ HGEDITOR="~/tools/testeditor.exe" hg debuginstall
  checking encoding (ascii)...
  checking Python executable (*) (glob)
  checking Python implementation (*) (glob)
  checking Python version (2.*) (glob) (no-py3 !)
  checking Python version (3.*) (glob) (py3 !)
  checking Python lib (.*[Ll]ib.*)... (re)
  checking Python security support (*) (glob)
    TLS 1.2 not supported by Python install; network connections lack modern security (?)
    SNI not supported by Python install; may have connectivity issues with some servers (?)
  checking Rust extensions \((installed|missing)\) (re)
  checking Mercurial version (*) (glob)
  checking Mercurial custom build (*) (glob)
  checking module policy (*) (glob)
  checking installed modules (*mercurial)... (glob)
  checking registered compression engines (*zlib*) (glob)
  checking available compression engines (*zlib*) (glob)
  checking available compression engines for wire protocol (*zlib*) (glob)
  checking "re2" regexp engine \((available|missing)\) (re)
  checking "re2" regexp engine Rust bindings \((installed|missing)\) (re) (rust !)
  checking templates (*mercurial?templates)... (glob)
  checking default template (*mercurial?templates?map-cmdline.default) (glob)
  checking commit editor... ($TESTTMP/tools/testeditor.exe)
  checking username (test)
  no problems detected

print out the binary post-shlexsplit in the error message when commit editor is
not found (this is intentionally using backslashes to mimic a windows usecase).
  $ HGEDITOR="c:\foo\bar\baz.exe -y -z" hg debuginstall
  checking encoding (ascii)...
  checking Python executable (*) (glob)
  checking Python implementation (*) (glob)
  checking Python version (2.*) (glob) (no-py3 !)
  checking Python version (3.*) (glob) (py3 !)
  checking Python lib (.*[Ll]ib.*)... (re)
  checking Python security support (*) (glob)
    TLS 1.2 not supported by Python install; network connections lack modern security (?)
    SNI not supported by Python install; may have connectivity issues with some servers (?)
  checking Rust extensions \((installed|missing)\) (re)
  checking Mercurial version (*) (glob)
  checking Mercurial custom build (*) (glob)
  checking module policy (*) (glob)
  checking installed modules (*mercurial)... (glob)
  checking registered compression engines (*zlib*) (glob)
  checking available compression engines (*zlib*) (glob)
  checking available compression engines for wire protocol (*zlib*) (glob)
  checking "re2" regexp engine \((available|missing)\) (re)
  checking "re2" regexp engine Rust bindings \((installed|missing)\) (re) (rust !)
  checking templates (*mercurial?templates)... (glob)
  checking default template (*mercurial?templates?map-cmdline.default) (glob)
  checking commit editor... (c:\foo\bar\baz.exe) (windows !)
   Can't find editor 'c:\foo\bar\baz.exe' in PATH (windows !)
  checking commit editor... (c:foobarbaz.exe) (no-windows !)
   Can't find editor 'c:foobarbaz.exe' in PATH (no-windows !)
   (specify a commit editor in your configuration file)
  checking username (test)
  1 problems detected, please check your install!
  [1]

debuginstall extension support
  $ hg debuginstall --config extensions.fsmonitor= --config fsmonitor.watchman_exe=false | grep atchman
  fsmonitor checking for watchman binary... (false)
   watchman binary missing or broken: warning: Watchman unavailable: watchman exited with code 1
Verify the json works too:
  $ hg debuginstall --config extensions.fsmonitor= --config fsmonitor.watchman_exe=false -Tjson | grep atchman
    "fsmonitor-watchman": "false",
    "fsmonitor-watchman-error": "warning: Watchman unavailable: watchman exited with code 1",

Verify that Mercurial is installable with pip. Note that this MUST be
the last test in this file, because we do some nasty things to the
shell environment in order to make the virtualenv work reliably.

On Python 3, we use the venv module, which is part of the standard library.
But some Linux distros strip out this module's functionality involving pip,
so we have to look for the ensurepip module, which these distros strip out
completely.
On Python 2, we use the 3rd party virtualenv module, if available.

  $ cd $TESTTMP
  $ unset PYTHONPATH

#if py3 ensurepip
  $ "$PYTHON" -m venv installenv >> pip.log

Note: we use this weird path to run pip and hg to avoid platform differences,
since it's bin on most platforms but Scripts on Windows.
  $ ./installenv/*/pip install --no-index $TESTDIR/.. >> pip.log
    Failed building wheel for mercurial (?)
  $ ./installenv/*/hg debuginstall || cat pip.log
  checking encoding (ascii)...
  checking Python executable (*) (glob)
  checking Python implementation (*) (glob)
  checking Python version (3.*) (glob)
  checking Python lib (*)... (glob)
  checking Python security support (*) (glob)
  checking Rust extensions \((installed|missing)\) (re)
  checking Mercurial version (*) (glob)
  checking Mercurial custom build (*) (glob)
  checking module policy (*) (glob)
  checking installed modules (*/mercurial)... (glob)
  checking registered compression engines (*) (glob)
  checking available compression engines (*) (glob)
  checking available compression engines for wire protocol (*) (glob)
  checking "re2" regexp engine \((available|missing)\) (re)
  checking "re2" regexp engine Rust bindings \((installed|missing)\) (re) (rust !)
  checking templates ($TESTTMP/installenv/*/site-packages/mercurial/templates)... (glob)
  checking default template ($TESTTMP/installenv/*/site-packages/mercurial/templates/map-cmdline.default) (glob)
  checking commit editor... (*) (glob)
  checking username (test)
  no problems detected
#endif

#if no-py3 virtualenv

Note: --no-site-packages is deprecated, but some places have an
ancient virtualenv from their linux distro or similar and it's not yet
the default for them.

  $ "$PYTHON" -m virtualenv --no-site-packages --never-download installenv >> pip.log
  DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7. (?)
  DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7. More details about Python 2 support in pip, can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support (?)

Note: we use this weird path to run pip and hg to avoid platform differences,
since it's bin on most platforms but Scripts on Windows.
  $ ./installenv/*/pip install --no-index $TESTDIR/.. >> pip.log
  DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7. (?)
  DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7. More details about Python 2 support in pip, can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support (?)
  $ ./installenv/*/hg debuginstall || cat pip.log
  checking encoding (ascii)...
  checking Python executable (*) (glob)
  checking Python implementation (*) (glob)
  checking Python version (2.*) (glob)
  checking Python lib (*)... (glob)
  checking Python security support (*) (glob)
    TLS 1.2 not supported by Python install; network connections lack modern security (?)
    SNI not supported by Python install; may have connectivity issues with some servers (?)
  checking Rust extensions \((installed|missing)\) (re)
  checking Mercurial version (*) (glob)
  checking Mercurial custom build (*) (glob)
  checking module policy (*) (glob)
  checking installed modules (*/mercurial)... (glob)
  checking registered compression engines (*) (glob)
  checking available compression engines (*) (glob)
  checking available compression engines for wire protocol (*) (glob)
  checking "re2" regexp engine \((available|missing)\) (re)
  checking "re2" regexp engine Rust bindings \((installed|missing)\) (re) (rust !)
  checking templates ($TESTTMP/installenv/*/site-packages/mercurial/templates)... (glob)
  checking default template ($TESTTMP/installenv/*/site-packages/mercurial/templates/map-cmdline.default) (glob)
  checking commit editor... (*) (glob)
  checking username (test)
  no problems detected
#endif