Make `pyenv init --path` usable as a `pyenv init -` substitute

We're going to eliminate the need to mandatorily use `pyenv init --path`.
We can't delete it yet for backward compatibility.
Besides, there's one other use case for it: to enable shims but without
shell integration, e.g. for noninteractive shells.

To be a full-fledged replacement for `pyenv init -` however,
it needs to do rehashing.

README.md

@@ -528,7 +528,7 @@ opposed to this idea. Here's what `eval "$(pyenv init -)"` actually does:
    for some reason you need `pyenv` to be a real script rather than a
    shell function, you can safely skip it.
 
-`eval "$(pyenv init --path)"` only does item 1.
+`eval "$(pyenv init --path)"` only does items 1 and 3.
 
 To see exactly what happens under the hood for yourself, run `pyenv init -`
 or `pyenv init --path`.

libexec/pyenv-init

@@ -57,6 +57,7 @@ function main() {
     ;;
   "path")
     print_path
+    print_rehash
     exit 0
     ;;
   "print")
@@ -64,6 +65,7 @@ function main() {
     print_path
     print_env
     print_completion
+    print_rehash
     print_shell_function
     exit 0
     ;;
@@ -168,7 +170,9 @@ function print_completion() {
   if [ -r "$completion" ]; then
     echo "source '$completion'"
   fi
+}
 
+function print_rehash() {
   if [ -z "$no_rehash" ]; then
     echo 'command pyenv rehash 2>/dev/null'
   fi

test/init.bats

@@ -17,6 +17,13 @@ load test_helper
   assert_line "command pyenv rehash 2>/dev/null"
 }
 
+@test "auto rehash for --path" {
+  run pyenv-init --path
+  assert_success
+  assert_line "command pyenv rehash 2>/dev/null"
+}
+
+
 @test "setup shell completions" {
   root="$(cd $BATS_TEST_DIRNAME/.. && pwd)"
   run pyenv-init - bash