Fix pipefail error caused by piping output to head (#270)

entrypoint.sh

@@ -78,20 +78,25 @@ git fetch --tags
 tagFmt="^v?[0-9]+\.[0-9]+\.[0-9]+$"
 preTagFmt="^v?[0-9]+\.[0-9]+\.[0-9]+(-$suffix\.[0-9]+)$"
 
-# get latest tag that looks like a semver (with or without v)
+# get the git refs
+git_refs=
 case "$tag_context" in
-    *repo*) 
-        tag="$(git for-each-ref --sort=-v:refname --format '%(refname:lstrip=2)' | (grep -E "$tagFmt" || true) | head -n 1)"
-        pre_tag="$(git for-each-ref --sort=-v:refname --format '%(refname:lstrip=2)' | (grep -E "$preTagFmt" || true) | head -n 1)"
+    *repo*)
+        git_refs=$(git for-each-ref --sort=-v:refname --format '%(refname:lstrip=2)')
         ;;
-    *branch*) 
-        tag="$(git tag --list --merged HEAD --sort=-v:refname | (grep -E "$tagFmt" || true) | head -n 1)"
-        pre_tag="$(git tag --list --merged HEAD --sort=-v:refname | (grep -E "$preTagFmt" || true) | head -n 1)"
+    *branch*)
+        git_refs=$(git tag --list --merged HEAD --sort=-v:refname)
         ;;
     * ) echo "Unrecognised context"
         exit 1;;
 esac
 
+# get the latest tag that looks like a semver (with or without v)
+matching_tag_refs=$( (grep -E "$tagFmt" <<< "$git_refs") || true)
+matching_pre_tag_refs=$( (grep -E "$preTagFmt" <<< "$git_refs") || true)
+tag=$(head -n 1 <<< "$matching_tag_refs")
+pre_tag=$(head -n 1 <<< "$matching_pre_tag_refs")
+
 # if there are none, start tags at INITIAL_VERSION
 if [ -z "$tag" ]
 then
@@ -140,7 +145,7 @@ then
 fi
 
 # get the merge commit message looking for #bumps
-declare -A history_type=( 
+declare -A history_type=(
     ["last"]="$(git show -s --format=%B)" \
     ["full"]="$(git log "${default_branch}"..HEAD --format=%B)" \
     ["compare"]="$(git log "${tag_commit}".."${commit}" --format=%B)" \
@@ -152,26 +157,26 @@ case "$log" in
     *$major_string_token* ) new=$(semver -i major "$tag"); part="major";;
     *$minor_string_token* ) new=$(semver -i minor "$tag"); part="minor";;
     *$patch_string_token* ) new=$(semver -i patch "$tag"); part="patch";;
-    *$none_string_token* ) 
+    *$none_string_token* )
         echo "Default bump was set to none. Skipping..."
         setOutput "old_tag" "$tag"
         setOutput "new_tag" "$tag"
         setOutput "tag" "$tag"
         setOutput "part" "$default_semvar_bump"
         exit 0;;
-    * ) 
+    * )
         if [ "$default_semvar_bump" == "none" ]
         then
             echo "Default bump was set to none. Skipping..."
             setOutput "old_tag" "$tag"
             setOutput "new_tag" "$tag"
             setOutput "tag" "$tag"
             setOutput "part" "$default_semvar_bump"
-            exit 0 
-        else 
+            exit 0
+        else
             new=$(semver -i "${default_semvar_bump}" "$tag")
-            part=$default_semvar_bump 
-        fi 
+            part=$default_semvar_bump
+        fi
         ;;
 esac