feat: add semver sorting for multibranch check (fixes #20)

README.md

@@ -36,6 +36,17 @@ Tracks the commits in a [git](http://git-scm.com/) repository.
 * `ignore_branches`: *Optional.* Used in conjunction with and applied after
   the `branches` pattern.  See example for common use case.
 
+* `sort`: *Optional.* When set to `semver`, branches matched by the
+  `branches` pattern will be sorted by semantic version (highest first)
+  before processing. This ensures the branch with the highest version
+  number is always checked first. Only meaningful in multi-branch mode.
+
+* `sort_prefix`: *Optional.* Used in conjunction with `sort: semver`. A
+  regex pattern that is stripped from the branch name before extracting
+  the version for comparison. For example, `(release|hotfix)/` would
+  strip the prefix from `release/2.0.0` and `hotfix/1.0.1` to compare
+  `2.0.0` vs `1.0.1`.
+
 * `redis`: *Optional.*  Contains the information required to use a specified
   Redis server to store multibranch historic references so that they don't
   clutter up the ref lines.  It consists of the following subkeys:
@@ -102,6 +113,19 @@ resources:
     ignore_branches: '(master|deploy)'
 ```
 
+Detecting the highest version release or hotfix branch first
+
+``` yaml
+resources:
+- name: my-releases
+  type: git-multibranch
+  source:
+    uri: git@github.com:my-org/my-repo.git
+    branches: '(release|hotfix)/\d+\.\d+\.\d+'
+    sort: semver
+    sort_prefix: '(release|hotfix)/'
+```
+
 ## Behavior
 
 ### `check`: Check for new commits.

assets/check

@@ -26,6 +26,8 @@ ignore_branches=$(jq -r '.source.ignore_branches // ""' < $payload)
 paths="$(jq -r '(.source.paths // ["."])[]' < $payload)" # those "'s are important
 ignore_paths="$(jq -r '":!" + (.source.ignore_paths // [])[]' < $payload)" # these ones too
 last_refs=$(jq -r '.version.ref // ""' < $payload)
+sort_mode=$(jq -r '.source.sort // ""' < $payload)
+sort_prefix=$(jq -r '.source.sort_prefix // ""' < $payload)
 
 ## Redis stuff to support cleaner multibranch behaviour
 redis_host=$(jq -r '.source.redis.host // ""' < $payload)
@@ -75,6 +77,29 @@ filter_branches() {
   echo "$branch_refs"
 }
 
+sort_branches_semver() {
+  # When sort mode is semver, strip the prefix from branch names,
+  # sort by major.minor.patch descending, then restore original format.
+  # This ensures the highest version is processed first.
+  if [ "$sort_mode" = "semver" ] ; then
+    local input="$(cat)"
+    if [ -n "$sort_prefix" ] ; then
+      echo "$input" | \
+        awk -F: -v prefix="$sort_prefix" '{
+          branch = $2;
+          ver = branch;
+          gsub(prefix, "", ver);
+          print ver "\t" $0
+        }' | sort -t. -k1,1rn -k2,2rn -k3,3rn | \
+        cut -f2
+    else
+      echo "$input"
+    fi
+  else
+    cat
+  fi
+}
+
 get_refs() {
   local ref="$1"
   git log --grep '\[ci skip\]' --invert-grep --format='%H' $(log_range $ref) $(paths_search "$paths" "$ignore_paths")
@@ -128,7 +153,8 @@ get_branch_refs() {
        grep -e '^[0-9a-f]\{40\}:' | \
        sort -t: -k1 | grep ":origin/" | \
        sed -e 's/:origin\//:/' | \
-       filter_branches)"
+       filter_branches | \
+       sort_branches_semver)"
 
   # Find the first branch that has a different ref
   for branch_and_ref in $current_branches ; do

test/check_multi.sh

@@ -296,6 +296,50 @@ it_can_find_successive_branches_with_multiple_commits_with_redis() {
   fi
 }
 
+it_sorts_branches_by_semver_highest_first() {
+  local repo=$(init_repo)
+
+  # Create release branches with different versions
+  local ref1=$(make_commit_to_branch $repo "release/1.0.0")
+  local ref2=$(make_commit_to_branch $repo "release/2.0.0")
+  local ref3=$(make_commit_to_branch $repo "release/1.5.0")
+
+  # With semver sort, the highest version (release/2.0.0) should always be returned first
+  # regardless of commit hash ordering
+  local result=$(test_check uri $repo branches 'release/.*' sort semver sort_prefix 'release/')
+
+  local returned_branch=$(echo "$result" | jq -r '.[0].ref' | sed 's/^[0-9a-f]*://' | awk '{print $1}')
+
+  if [ "$returned_branch" != "release/2.0.0" ] ; then
+    echo "Expected release/2.0.0 to be returned first, got: $returned_branch"
+    return 1
+  fi
+
+  echo "Correctly returned release/2.0.0 (highest semver) first"
+}
+
+it_sorts_mixed_release_hotfix_branches_by_semver() {
+  local repo=$(init_repo)
+
+  # Create mixed release and hotfix branches
+  local ref1=$(make_commit_to_branch $repo "release/1.0.0")
+  local ref2=$(make_commit_to_branch $repo "hotfix/1.0.1")
+  local ref3=$(make_commit_to_branch $repo "release/2.0.0")
+  local ref4=$(make_commit_to_branch $repo "hotfix/2.0.1")
+
+  # With semver sort and prefix stripping, hotfix/2.0.1 (version 2.0.1) should be first
+  local result=$(test_check uri $repo branches '(release|hotfix)/.*' sort semver sort_prefix '(release|hotfix)/')
+
+  local returned_branch=$(echo "$result" | jq -r '.[0].ref' | sed 's/^[0-9a-f]*://' | awk '{print $1}')
+
+  if [ "$returned_branch" != "hotfix/2.0.1" ] ; then
+    echo "Expected hotfix/2.0.1 to be returned first (highest semver 2.0.1), got: $returned_branch"
+    return 1
+  fi
+
+  echo "Correctly returned hotfix/2.0.1 (highest semver 2.0.1) first"
+}
+
 # --- RUN TESTS ---
 
 run it_can_perform_initial_check
@@ -308,3 +352,5 @@ run it_can_find_successive_branches_with_multiple_commits
 run it_ignores_branches_with_only_skip_commits
 run it_can_find_branches_that_has_multiple_commits_with_latest_being_skipped
 run it_can_find_successive_branches_with_multiple_commits_with_redis
+run it_sorts_branches_by_semver_highest_first
+run it_sorts_mixed_release_hotfix_branches_by_semver

test/helpers.sh

@@ -192,6 +192,22 @@ test_check() {
         }")"
         shift;;
 
+      "sort" )
+        addition="$(jq -n "{
+          source: {
+            sort: $(echo "$1" | jq -R '.')
+          }
+        }")"
+        shift;;
+
+      "sort_prefix" )
+        addition="$(jq -n "{
+          source: {
+            sort_prefix: $(echo "$1" | jq -R '.')
+          }
+        }")"
+        shift;;
+
       "redis" )
         addition="$(jq -n "{
           source: {