Fix python path discovery if not called python

.azure-pipelines/jobs/run-tests-windows.yml

@@ -4,6 +4,12 @@ steps:
   inputs:
     versionSpec: '$(python.version)'
     architecture: '$(python.architecture)'
+    addToPath: true
+
+- powershell: |
+    Write-Host "##vso[task.setvariable variable=PIPENV_DEFAULT_PYTHON_VERSION]$env:PYTHON_VERSION"
+  env:
+    PYTHON_VERSION: $(python.version)
 
 - template: ../steps/install-dependencies.yml
 

.azure-pipelines/jobs/run-tests.yml

@@ -4,23 +4,14 @@ steps:
   inputs:
     versionSpec: '$(python.version)'
     architecture: '$(python.architecture)'
+    addToPath: true
+
+- script: |
+      echo '##vso[task.setvariable variable=PIPENV_DEFAULT_PYTHON_VERSION]$(python.version)'
 
 - template: ../steps/install-dependencies.yml
 
-- bash: |
-    mkdir -p "$AGENT_HOMEDIRECTORY/.virtualenvs"
-    mkdir -p "$WORKON_HOME"
-    pip install certifi
-    export GIT_SSL_CAINFO="$(python -m certifi)"
-    export LANG="C.UTF-8"
-    export PIP_PROCESS_DEPENDENCY_LINKS="1"
-    echo "Path $PATH"
-    echo "Installing Pipenv…"
-    pip install -e "$(pwd)[test]" --upgrade
-    pipenv install --deploy --dev
-    pipenv run pip install -e "$(pwd)[test]" --upgrade
-    echo pipenv --venv && echo pipenv --py && echo pipenv run python --version
-  displayName: Make Virtualenv
+- template: ../steps/create-virtualenv-linux.yml
 
 - script: |
     # Fix Git SSL errors

.azure-pipelines/steps/create-virtualenv-linux.yml

@@ -0,0 +1,14 @@
+steps:
+- bash: |
+    mkdir -p "$AGENT_HOMEDIRECTORY/.virtualenvs"
+    mkdir -p "$WORKON_HOME"
+    pip install certifi
+    export GIT_SSL_CAINFO="$(python -m certifi)"
+    export LANG="C.UTF-8"
+    export PIP_PROCESS_DEPENDENCY_LINKS="1"
+    echo "Path $PATH"
+    echo "Installing Pipenv…"
+    pipenv install --deploy --dev
+    pipenv run pip install -e "$(pwd)[test]" --upgrade
+    echo pipenv --venv && echo pipenv --py && echo pipenv run python --version
+  displayName: Make Virtualenv

.azure-pipelines/steps/create-virtualenv.yml

@@ -1,6 +1,30 @@
 steps:
-- script: |
-    virtualenv D:\.venv
-    D:\.venv\Scripts\pip.exe install -e .[test] && D:\.venv\Scripts\pipenv install --dev && D:\.venv\Scripts\pipenv run pip install -e .[test]
-    echo D:\.venv\Scripts\pipenv --venv && echo D:\.venv\Scripts\pipenv --py && echo D:\.venv\Scripts\pipenv run python --version
+
+- powershell: |
+    $env:PY_EXE=$(python -c "import sys; print(sys.executable)")
+    if (!$env:PY_EXE) {
+        $env:PY_EXE="python"
+    }
+    Write-Host "##vso[task.setvariable variable=PY_EXE]"$env:PY_EXE
+    Write-Host "Found Python: $env:PY_EXE"
+    Invoke-Expression "$env:PY_EXE -m virtualenv D:\.venv"
+    Write-Host "##vso[task.setvariable variable=VIRTUAL_ENV]D:\.venv"
+    Invoke-Expression "D:\.venv\Scripts\activate.ps1"
+    $env:VIRTUAL_ENV="D:\.venv"
+    Write-Host "Installing local package..."
+    Invoke-Expression "$env:PY_EXE -m pip install -e .[test] --upgrade"
+    Write-Host "upgrading local package in virtual env"
+    $venv_scripts = Join-Path -path D:\.venv -childpath Scripts
+    $venv_py = Join-Path -path $venv_scripts -childpath python.exe
+    Invoke-Expression "$venv_py -m pip install -e .[test] --upgrade"
+    Write-Host "Installing pipenv development packages"
+    Invoke-Expression "$venv_py -m pipenv install --dev"
+    Write-Host "Installing local package in pipenv environment"
+    Invoke-Expression "$venv_py -m pipenv run pip install -e .[test]"
+    Write-Host "Printing metadata"
+    Write-Host $(Invoke-Expression "$venv_py -m pipenv --venv")
+    Write-Host $(Invoke-Expression "$venv_py -m pipenv --py")
+    Write-Host $(Invoke-Expression "$venv_py -m pipenv run python --version")
   displayName: Make Virtualenv
+  env:
+    PIPENV_DEFAULT_PYTHON_VERSION: $(PIPENV_DEFAULT_PYTHON_VERSION)

.azure-pipelines/steps/install-dependencies.yml

@@ -1,3 +1,3 @@
 steps:
-- script: 'python -m pip install --upgrade pip && python -m pip install -e .[test]'
+- script: 'python -m pip install --upgrade pip setuptools wheel && python -m pip install -e .[test] --upgrade'
   displayName: Upgrade Pip & Install Pipenv

.gitignore

@@ -145,6 +145,10 @@ venv.bak/
 # mypy
 .mypy_cache/
 
+# Temporarily generating these with pytype locally for type safety
+typeshed/
+pytype.cfg
+
 ### Python Patch ###
 .venv/
 

news/2783.bugfix.rst

@@ -0,0 +1,2 @@
+Fixed an issue which caused errors due to reliance on the system utilities ``which`` and ``where`` which may not always exist on some systems.
+- Fixed a bug which caused periodic failures in python discovery when executables named ``python`` were not present on the target ``$PATH``.

pipenv/__init__.py

@@ -26,16 +26,6 @@
 warnings.filterwarnings("ignore", category=ResourceWarning)
 warnings.filterwarnings("ignore", category=UserWarning)
 
-if sys.version_info >= (3, 1) and sys.version_info <= (3, 6):
-    if sys.stdout.isatty() and sys.stderr.isatty():
-        import io
-        import atexit
-        stdout_wrapper = io.TextIOWrapper(sys.stdout.buffer, encoding='utf8')
-        atexit.register(stdout_wrapper.close)
-        stderr_wrapper = io.TextIOWrapper(sys.stderr.buffer, encoding='utf8')
-        atexit.register(stderr_wrapper.close)
-        sys.stdout = stdout_wrapper
-        sys.stderr = stderr_wrapper
 
 os.environ["PIP_DISABLE_PIP_VERSION_CHECK"] = fs_str("1")
 
@@ -46,6 +36,19 @@
 except Exception:
     pass
 
+from .vendor.vistir.misc import get_wrapped_stream
+if sys.version_info >= (3, 0):
+    stdout = sys.stdout.buffer
+    stderr = sys.stderr.buffer
+else:
+    stdout = sys.stdout
+    stderr = sys.stderr
+
+
+sys.stderr = get_wrapped_stream(stderr)
+sys.stdout = get_wrapped_stream(stdout)
+
+
 from .cli import cli
 from . import resolver
 

pipenv/cmdparse.py

@@ -10,7 +10,7 @@ class ScriptEmptyError(ValueError):
 
 
 def _quote_if_contains(value, pattern):
-    if next(re.finditer(pattern, value), None):
+    if next(iter(re.finditer(pattern, value)), None):
         return '"{0}"'.format(re.sub(r'(\\*)"', r'\1\1\\"', value))
     return value