feat!: retrieve remote default branch (#283)

helm-git-plugin.sh

@@ -82,6 +82,15 @@ git_try() {
   GIT_TERMINAL_PROMPT=0 git ls-remote "$_git_repo" --refs >"${git_output}" 2>&1 || return 1
 }
 
+#git_get_default_branch(git_repo_path)
+git_get_default_branch() {
+  _git_repo="${1?Missing git_repo as first parameter}"
+
+  # Fetch default branch from remote
+  _git_symref=$(GIT_TERMINAL_PROMPT=0  git ls-remote --symref "${_git_repo}" origin HEAD 2>"${git_output}") || return
+  echo "$_git_symref" | awk '/^ref:/ {sub(/refs\/heads\//, "", $2); print $2}' || return
+}
+
 #git_fetch_ref(git_repo_path, git_ref)
 git_fetch_ref() {
   _git_repo_path="${1?Missing git_repo_path as first parameter}"
@@ -122,7 +131,7 @@ git_cache_intercept() {
   if [ -z "$(GIT_DIR="${repo_path}" git tag -l "${_git_ref}" 2>"${git_output}")" ]; then
     debug "Did not find ${_git_ref} in our cache for ${_git_repo}, fetching...."
     # This fetches properly tags, annotated tags, branches and commits that match the name and leave them at the right place
-    git_fetch_ref "${repo_path}" "${git_ref}" ||
+    git_fetch_ref "${repo_path}" "${_git_ref}" ||
       debug "Could not fetch ${_git_ref}" && return 1
   else
     debug "Ref ${_git_ref} was already cached for ${_git_repo}"
@@ -306,8 +315,14 @@ parse_uri() {
   git_ref=$(echo "$_uri_query" | sed '/^.*ref=\([^&#]*\).*$/!d;s//\1/')
   # TODO: Validate git_ref
   if [ -z "$git_ref" ]; then
-    warning "git_ref is empty, defaulted to 'master'. Prefer to pin GIT ref in URI."
-    git_ref="master"
+    warning "git_ref was not given, trying to discover default branch from remote. Prefer to pin GIT ref in URI."
+    git_ref=$(git_get_default_branch "$git_repo")
+    if [ -z "$git_ref" ]; then
+      warning "git_ref could not be discovered from remote. Defaulting to 'master'. Prefer to pin GIT ref in URI."
+      git_ref="master"
+    else
+      debug "Discovered default branch from remote: '$git_ref'. Prefer to pin GIT ref in URI."
+    fi
   fi
   readonly git_ref
   trace "git_ref: $git_ref"

tests/04-uri-validation.bats

@@ -30,13 +30,13 @@ load 'test-helper'
 @test "should fail and warning with bad path and no ref" {
     _run_helm_git "git+https://github.com/jetstack/cert-manager@contrib/charts/cert-manager/index.yaml?ref="
     [ $status = 1 ]
-    [ -n "$(echo $output | grep "git_ref is empty")" ]
+    [ -n "$(echo $output | grep "git_ref was not given")" ]
 }
 
 @test "should success and warning with no ref" {
     _run_helm_git "git+https://github.com/jetstack/cert-manager@deploy/charts/index.yaml"
     [ $status = 0 ]
-    [ -n "$(echo $output | grep "git_ref is empty")" ]
+    [ -n "$(echo $output | grep "git_ref was not given")" ]
 }
 
 @test "should success with username" {