Speed up pyenv prefix by not constructing advice text when it would be discarded (#3005)

by adding an internal flag

libexec/pyenv-prefix

@@ -30,9 +30,9 @@ OLDIFS="$IFS"
 { IFS=:
   for version in ${PYENV_VERSION}; do
     if [ "$version" = "system" ]; then
-      if PYTHON_PATH="$(PYENV_VERSION="${version}" pyenv-which python 2>/dev/null)" || \
-          PYTHON_PATH="$(PYENV_VERSION="${version}" pyenv-which python3 2>/dev/null)" || \
-          PYTHON_PATH="$(PYENV_VERSION="${version}" pyenv-which python2 2>/dev/null)"; then
+      if PYTHON_PATH="$(PYENV_VERSION="${version}" pyenv-which python --skip-advice 2>/dev/null)" || \
+          PYTHON_PATH="$(PYENV_VERSION="${version}" pyenv-which python3 --skip-advice 2>/dev/null)" || \
+          PYTHON_PATH="$(PYENV_VERSION="${version}" pyenv-which python2 --skip-advice 2>/dev/null)"; then
         shopt -s extglob
         # In some distros (Arch), Python can be found in sbin as well as bin
         PYENV_PREFIX_PATH="${PYTHON_PATH%/?(s)bin/*}"

libexec/pyenv-versions

@@ -128,9 +128,9 @@ print_version() {
 
 # Include "system" in the non-bare output, if it exists
 if [ -n "$include_system" ] && \
-    (PYENV_VERSION=system pyenv-which python >/dev/null 2>&1 || \
-     PYENV_VERSION=system pyenv-which python3 >/dev/null 2>&1 || \
-     PYENV_VERSION=system pyenv-which python2 >/dev/null 2>&1) ; then
+    (PYENV_VERSION=system pyenv-which python --skip-advice >/dev/null 2>&1 || \
+     PYENV_VERSION=system pyenv-which python3 --skip-advice >/dev/null 2>&1 || \
+     PYENV_VERSION=system pyenv-which python2 --skip-advice >/dev/null 2>&1) ; then
   print_version system "/"
 fi
 

libexec/pyenv-which

@@ -2,13 +2,14 @@
 #
 # Summary: Display the full path to an executable
 #
-# Usage: pyenv which <command> [--nosystem]
+# Usage: pyenv which <command> [--nosystem] [--skip-advice]
 #
 # Displays the full path to the executable that pyenv will invoke when
 # you run the given command.
 # Use --nosystem argument in case when you don't need to search command in the 
 # system environment.
-#
+# Internal switch --skip-advice used to skip printing an error message on a
+# failed search.
 
 set -e
 [ -n "$PYENV_DEBUG" ] && set -x
@@ -18,11 +19,27 @@ if [ "$1" = "--complete" ]; then
   exec pyenv-shims --short
 fi
 
-if [ "$2" = "--nosystem" ]; then
-  system=""
-else
-  system="system"
-fi
+system="system"
+SKIP_ADVICE=""
+PYENV_COMMAND="$1"
+
+while [[ $# -gt 0 ]]
+do
+  case "$1" in
+    --skip-advice)
+      SKIP_ADVICE=1
+      shift
+      ;;
+    --nosystem)
+      system=""
+      shift
+      ;;
+    *)
+      shift
+      ;;
+  esac
+done
+
 
 remove_from_path() {
   local path_to_remove="$1"
@@ -36,8 +53,6 @@ remove_from_path() {
   echo "${result#:}"
 }
 
-PYENV_COMMAND="$1"
-
 if [ -z "$PYENV_COMMAND" ]; then
   pyenv-help --usage which >&2
   exit 1
@@ -85,16 +100,17 @@ else
   fi
 
   echo "pyenv: $PYENV_COMMAND: command not found" >&2
-
-  versions="$(pyenv-whence "$PYENV_COMMAND" || true)"
-  if [ -n "$versions" ]; then
-    { echo
-      echo "The \`$1' command exists in these Python versions:"
-      echo "$versions" | sed 's/^/  /g'
-      echo
-      echo "Note: See 'pyenv help global' for tips on allowing both"
-      echo "      python2 and python3 to be found."
-    } >&2
+  if [ -z "$SKIP_ADVICE" ]; then
+    versions="$(pyenv-whence "$PYENV_COMMAND" || true)"
+    if [ -n "$versions" ]; then
+      { echo
+        echo "The \`$PYENV_COMMAND' command exists in these Python versions:"
+        echo "$versions" | sed 's/^/  /g'
+        echo
+        echo "Note: See 'pyenv help global' for tips on allowing both"
+        echo "      python2 and python3 to be found."
+      } >&2
+    fi
   fi
 
   exit 127

test/which.bats

@@ -155,3 +155,15 @@ exit
   PYENV_VERSION=3.4 run pyenv-which python
   assert_success "version=3.4.2"
 }
+
+@test "skip advice supresses error messages" {
+  create_executable "2.7" "python"
+  create_executable "3.3" "py.test"
+  create_executable "3.4" "py.test"
+
+  PYENV_VERSION=2.7 run pyenv-which py.test --skip-advice
+  assert_failure
+  assert_output <<OUT
+pyenv: py.test: command not found
+OUT
+}