Add support for RC versions to asdf update command

docs/core-configuration.md

@@ -41,6 +41,7 @@ legacy_version_file = yes
 **Settings**
 
 - `legacy_version_file` - defaults to `no`. If set to yes it will cause plugins that support this feature to read the version files used by other version managers (e.g. `.ruby-version` in the case of Ruby's `rbenv`).
+- `use_release_candidates` - defaults to `no`. If set to yes it will cause the `asdf update` command to upgrade to the latest release candidate release instead of the latest semantic version.
 
 ## Environment Variables
 

lib/commands/update.sh

@@ -26,7 +26,14 @@ do_update() {
   else
     # Update to latest release
     git fetch origin --tags || exit 1
+
+    if [ "$(get_asdf_config_value "use_release_candidates")" = "yes" ]; then
+      # Use the latest tag whether or not it is an RC
       tag=$(git tag | sort_versions | sed '$!d') || exit 1
+    else
+      # Exclude RC tags when selecting latest tag
+      tag=$(git tag | sort_versions | grep -vi "rc" | sed '$!d') || exit 1
+    fi
 
     # Update
     git checkout "$tag" || exit 1

test/update_command.bats

@@ -29,11 +29,22 @@ teardown() {
   [ $(git rev-parse --abbrev-ref HEAD) = "master" ]
 }
 
-@test "update_command should checkout the latest tag" {
+@test "update_command should checkout the latest non-RC tag" {
+  local tag=$(git tag | grep -vi "rc" | head -1)
+  run update_command
+  [ "$status" -eq 0 ]
+  cd $ASDF_DIR
+  echo $(git tag) | grep $tag
+  [ "$status" -eq 0 ]
+}
+
+@test "update_command should checkout the latest tag when configured with use_release_candidates = yes" {
+  local tag=$(git tag | head -1)
+  export ASDF_CONFIG_DEFAULT_FILE=$BATS_TMPDIR/asdfrc_defaults
+  echo "use_release_candidates = yes" > $ASDF_CONFIG_DEFAULT_FILE
   run update_command
   [ "$status" -eq 0 ]
   cd $ASDF_DIR
-  local tag=$(git describe --tag)
   echo $(git tag) | grep $tag
   [ "$status" -eq 0 ]
 }