Support pyenv-version-file-write --force

libexec/pyenv-version-file-write

@@ -1,9 +1,23 @@
 #!/usr/bin/env bash
-# Usage: pyenv version-file-write <file> <version>
+# Usage: pyenv version-file-write [-f|--force] <file> <version>
 
 set -e
 [ -n "$PYENV_DEBUG" ] && set -x
 
+while [[ $# -gt 0 ]]
+do
+    case "$1" in
+        -f|--force)
+            FORCE=1
+            shift
+            ;;
+        *)
+            break
+            ;;
+    esac
+done
+
+
 PYENV_VERSION_FILE="$1"
 shift || true
 versions=("$@")
@@ -14,7 +28,7 @@ if [ -z "$versions" ] || [ -z "$PYENV_VERSION_FILE" ]; then
 fi
 
 # Make sure the specified version is installed.
-pyenv-prefix "${versions[@]}" >/dev/null
+[[ -z $FORCE ]] && pyenv-prefix "${versions[@]}" >/dev/null
 
 # Write the version out to disk.
 # Create an empty file. Using "rm" might cause a permission error.

test/version-file-write.bats

@@ -21,6 +21,13 @@ setup() {
   assert [ ! -e ".python-version" ]
 }
 
+@test "setting nonexistent version succeeds with force" {
+  assert [ ! -e ".python-version" ]
+  run pyenv-version-file-write --force ".python-version" "2.7.6"
+  assert_success
+  assert [ -e ".python-version" ]
+}
+
 @test "writes value to arbitrary file" {
   mkdir -p "${PYENV_ROOT}/versions/2.7.6"
   assert [ ! -e "my-version" ]