add foolproof for -p argument.

find proper source version from pyenv if the given executable is only
basename or is a shim script.

bin/pyenv-virtualenv

@@ -318,10 +318,29 @@ if [ -n "${USE_PYVENV}" ]; then
   # Unset some arguments not supported by pyvenv
   unset QUIET
   unset VERBOSE
+  if [ -n "${VIRTUALENV_PYTHON}" ]; then
+    echo "pyenv-virtualenv: \`--python=${VIRTUALENV_PYTHON}' is not supported by pyvenv." 1>&2
+    exit 1
+  fi
 else
   if [ -n "${VIRTUALENV_PYTHON}" ]; then
+    if [[ "${VIRTUALENV_PYTHON}" == "${VIRTUALENV_PYTHON##*/}" ]] || [[ "${VIRTUALENV_PYTHON}" == "${PYENV_ROOT}/shims/"* ]]; then
+      python="$(pyenv-which "${VIRTUALENV_PYTHON##*/}" 2>/dev/null || true)"
+      if [ -x "${python}" ]; then
+        VIRTUALENV_OPTIONS[${#VIRTUALENV_OPTIONS[*]}]="--python=${python}"
+      else
+        python="$(PYENV_VERSION="$(pyenv-whence "${VIRTUALENV_PYTHON##*/}" 2>/dev/null | tail -n 1 || true)" pyenv-which "${VIRTUALENV_PYTHON##*/}" 2>/dev/null || true)"
+        if [ -x "${python}" ]; then
+          VIRTUALENV_OPTIONS[${#VIRTUALENV_OPTIONS[*]}]="--python=${python}"
+        else
+          echo "pyenv-virtualenv: \`${VIRTUALENV_PYTHON##*/}' is not installed in pyenv." 1>&2
+          exit 1
+        fi
+      fi
+    else
       VIRTUALENV_OPTIONS[${#VIRTUALENV_OPTIONS[*]}]="--python=${VIRTUALENV_PYTHON}"
     fi
+  fi
   if [ -z "${HAS_VIRTUALENV}" ]; then
     VIRTUALENV_VERSION="==${VIRTUALENV_VERSION}"
     pyenv-exec pip install $QUIET $VERBOSE "virtualenv${VIRTUALENV_VERSION%==}"

test/python.bats

@@ -0,0 +1,101 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+setup() {
+  export PYENV_ROOT="${TMP}/pyenv"
+  export PYENV_VERSION="2.7.8"
+  create_executable "${PYENV_VERSION}" "virtualenv"
+  remove_executable "${PYENV_VERSION}" "pyvenv"
+  stub pyenv-prefix "echo '${PYENV_ROOT}/versions/${PYENV_VERSION}'"
+  stub pyenv-prefix "echo '${PYENV_ROOT}/versions/${PYENV_VERSION}'"
+  stub pyenv-prefix "echo '${PYENV_ROOT}/versions/${PYENV_VERSION}'"
+  stub pyenv-hooks "virtualenv : echo"
+  stub pyenv-rehash " : true"
+  stub pyenv-version-name "echo \${PYENV_VERSION}"
+  stub curl true
+}
+
+teardown() {
+  unstub curl
+  unstub pyenv-version-name
+  unstub pyenv-prefix
+  unstub pyenv-hooks
+  unstub pyenv-rehash
+  rm -fr "$TMP"/*
+}
+
+@test "resolve python executable from enabled version" {
+  remove_executable "2.7.7" "python2.7"
+  create_executable "2.7.8" "python2.7"
+  remove_executable "2.7.9" "python2.7"
+
+  stub pyenv-exec "virtualenv --verbose --python=${PYENV_ROOT}/versions/2.7.8/bin/python2.7 ${PYENV_ROOT}/versions/venv : echo PYENV_VERSION=\${PYENV_VERSION} \"\$@\""
+  stub pyenv-exec "python -s -m ensurepip : true"
+  stub pyenv-which "python2.7 : echo ${PYENV_ROOT}/versions/2.7.8/bin/python2.7"
+
+  run pyenv-virtualenv --verbose --python=python2.7 venv
+
+  assert_output <<OUT
+PYENV_VERSION=2.7.8 virtualenv --verbose --python=${PYENV_ROOT}/versions/2.7.8/bin/python2.7 ${PYENV_ROOT}/versions/venv
+OUT
+  assert_success
+
+  unstub pyenv-which
+  unstub pyenv-exec
+
+  remove_executable "2.7.7" "python2.7"
+  remove_executable "2.7.8" "python2.7"
+  remove_executable "2.7.9" "python2.7"
+}
+
+@test "resolve python executable from other versions" {
+  remove_executable "2.7.7" "python2.7"
+  remove_executable "2.7.8" "python2.7"
+  create_executable "2.7.9" "python2.7"
+
+  stub pyenv-exec "virtualenv --verbose --python=${PYENV_ROOT}/versions/2.7.9/bin/python2.7 ${PYENV_ROOT}/versions/venv : echo PYENV_VERSION=\${PYENV_VERSION} \"\$@\""
+  stub pyenv-exec "python -s -m ensurepip : true"
+  stub pyenv-which "python2.7 : false"
+  stub pyenv-whence "python2.7 : echo 2.7.7; echo 2.7.8; echo 2.7.9"
+  stub pyenv-which "python2.7 : echo ${PYENV_ROOT}/versions/2.7.9/bin/python2.7"
+
+  run pyenv-virtualenv --verbose --python=python2.7 venv
+
+  assert_output <<OUT
+PYENV_VERSION=2.7.8 virtualenv --verbose --python=${PYENV_ROOT}/versions/2.7.9/bin/python2.7 ${PYENV_ROOT}/versions/venv
+OUT
+  assert_success
+
+  unstub pyenv-which
+  unstub pyenv-whence
+  unstub pyenv-exec
+
+  remove_executable "2.7.7" "python2.7"
+  remove_executable "2.7.8" "python2.7"
+  remove_executable "2.7.9" "python2.7"
+}
+
+@test "cannot resolve python executable" {
+  remove_executable "2.7.7" "python2.7"
+  remove_executable "2.7.8" "python2.7"
+  remove_executable "2.7.9" "python2.7"
+
+  stub pyenv-which "python2.7 : false"
+  stub pyenv-whence "python2.7 : false"
+  stub pyenv-which "python2.7 : false"
+
+  run pyenv-virtualenv --verbose --python=python2.7 venv
+
+  assert_output <<OUT
+pyenv-virtualenv: \`python2.7' is not installed in pyenv.
+OUT
+  assert_failure
+
+  unstub pyenv-which
+  unstub pyenv-whence
+
+  remove_executable "2.7.7" "python2.7"
+  remove_executable "2.7.8" "python2.7"
+  remove_executable "2.7.9" "python2.7"
+}

test/pyvenv.bats

@@ -101,20 +101,20 @@ OUT
   stub pyenv-prefix " : echo '${PYENV_ROOT}/versions/${PYENV_VERSION}'"
   stub pyenv-prefix " : echo '${PYENV_ROOT}/versions/${PYENV_VERSION}'"
   stub pyenv-exec "pip install virtualenv : echo PYENV_VERSION=\${PYENV_VERSION} \"\$@\""
-  stub pyenv-exec "virtualenv --python=python3 ${PYENV_ROOT}/versions/venv : echo PYENV_VERSION=\${PYENV_VERSION} \"\$@\""
+  stub pyenv-exec "virtualenv --python=${TMP}/python3 ${PYENV_ROOT}/versions/venv : echo PYENV_VERSION=\${PYENV_VERSION} \"\$@\""
   stub pyenv-exec "python -s -m ensurepip : true"
 
   remove_executable "3.4.1" "virtualenv"
   create_executable "3.4.1" "pyvenv"
 
-  run pyenv-virtualenv -p python3 venv
+  run pyenv-virtualenv -p ${TMP}/python3 venv
 
-  assert_success
   assert_output <<OUT
 PYENV_VERSION=3.4.1 pip install virtualenv
-PYENV_VERSION=3.4.1 virtualenv --python=python3 ${PYENV_ROOT}/versions/venv
+PYENV_VERSION=3.4.1 virtualenv --python=${TMP}/python3 ${PYENV_ROOT}/versions/venv
 rehashed
 OUT
+  assert_success
 
   unstub_pyenv
   unstub pyenv-exec
@@ -126,20 +126,20 @@ OUT
   stub pyenv-prefix " : echo '${PYENV_ROOT}/versions/${PYENV_VERSION}'"
   stub pyenv-prefix " : echo '${PYENV_ROOT}/versions/${PYENV_VERSION}'"
   stub pyenv-exec "pip install virtualenv : echo PYENV_VERSION=\${PYENV_VERSION} \"\$@\""
-  stub pyenv-exec "virtualenv --python=python3 ${PYENV_ROOT}/versions/venv : echo PYENV_VERSION=\${PYENV_VERSION} \"\$@\""
+  stub pyenv-exec "virtualenv --python=${TMP}/python3 ${PYENV_ROOT}/versions/venv : echo PYENV_VERSION=\${PYENV_VERSION} \"\$@\""
   stub pyenv-exec "python -s -m ensurepip : true"
 
   remove_executable "3.4.1" "virtualenv"
   create_executable "3.4.1" "pyvenv"
 
-  run pyenv-virtualenv --python=python3 venv
+  run pyenv-virtualenv --python=${TMP}/python3 venv
 
-  assert_success
   assert_output <<OUT
 PYENV_VERSION=3.4.1 pip install virtualenv
-PYENV_VERSION=3.4.1 virtualenv --python=python3 ${PYENV_ROOT}/versions/venv
+PYENV_VERSION=3.4.1 virtualenv --python=${TMP}/python3 ${PYENV_ROOT}/versions/venv
 rehashed
 OUT
+  assert_success
 
   unstub_pyenv
   unstub pyenv-exec

test/virtualenv.bats

@@ -73,19 +73,19 @@ OUT
   export PYENV_VERSION="3.2.1"
   stub_pyenv "${PYENV_VERSION}"
   stub pyenv-version-name "echo \${PYENV_VERSION}"
-  stub pyenv-exec "virtualenv --verbose --python=python ${PYENV_ROOT}/versions/venv : echo PYENV_VERSION=\${PYENV_VERSION} \"\$@\""
+  stub pyenv-exec "virtualenv --verbose --python=${TMP}/python ${PYENV_ROOT}/versions/venv : echo PYENV_VERSION=\${PYENV_VERSION} \"\$@\""
   stub pyenv-exec "python -s -m ensurepip : false"
   stub pyenv-exec "python -s */get-pip.py : true"
   stub curl true
 
-  run pyenv-virtualenv -v -p python venv
+  run pyenv-virtualenv -v -p ${TMP}/python venv
 
-  assert_success
   assert_output <<OUT
-PYENV_VERSION=3.2.1 virtualenv --verbose --python=python ${PYENV_ROOT}/versions/venv
+PYENV_VERSION=3.2.1 virtualenv --verbose --python=${TMP}/python ${PYENV_ROOT}/versions/venv
 Installing pip from https://bootstrap.pypa.io/get-pip.py...
 rehashed
 OUT
+  assert_success
 
   unstub_pyenv
   unstub pyenv-version-name
@@ -97,19 +97,19 @@ OUT
   export PYENV_VERSION="3.2.1"
   stub_pyenv "${PYENV_VERSION}"
   stub pyenv-version-name "echo \${PYENV_VERSION}"
-  stub pyenv-exec "virtualenv --verbose --python=python ${PYENV_ROOT}/versions/venv : echo PYENV_VERSION=\${PYENV_VERSION} \"\$@\""
+  stub pyenv-exec "virtualenv --verbose --python=${TMP}/python ${PYENV_ROOT}/versions/venv : echo PYENV_VERSION=\${PYENV_VERSION} \"\$@\""
   stub pyenv-exec "python -s -m ensurepip : false"
   stub pyenv-exec "python -s */get-pip.py : true"
   stub curl true
 
-  run pyenv-virtualenv --verbose --python=python venv
+  run pyenv-virtualenv --verbose --python=${TMP}/python venv
 
-  assert_success
   assert_output <<OUT
-PYENV_VERSION=3.2.1 virtualenv --verbose --python=python ${PYENV_ROOT}/versions/venv
+PYENV_VERSION=3.2.1 virtualenv --verbose --python=${TMP}/python ${PYENV_ROOT}/versions/venv
 Installing pip from https://bootstrap.pypa.io/get-pip.py...
 rehashed
 OUT
+  assert_success
 
   unstub_pyenv
   unstub pyenv-version-name