Start the release notes from the previous release of the same series

README.md

@@ -183,7 +183,7 @@ jobs:
 
 ## GitHub release (`github-release.yml`)
 
-Publishes a GitHub release of a version, tagging the commit the run is for, with notes generated from the merged pull requests. It pairs with `semver-version.yml`:
+Publishes a GitHub release of a version, tagging the commit the run is for, with notes generated from the pull requests merged since the previous release of the same series (the highest `<prefix>X.Y.Z` tag below the version, so a chart release of the same repository, `<chart>-X.Y.Z`, is not taken as the start). It pairs with `semver-version.yml`:
 
 - a **pre-release** replaces the release and the tag of the same name, so a pull request publishes its `X.Y.Z-PRE-<number>` again on every push;
 - a **release** never replaces one: a version that already exists fails the job.

scripts/github-release.sh

@@ -3,7 +3,11 @@
 #
 # A pre-release replaces the release and the tag of the same name, if there are any: a pull request
 # publishes the same X.Y.Z-PRE-<number> on every push. A release refuses to replace one: a version,
-# once released, does not change. The release notes are generated from the merged pull requests.
+# once released, does not change. The release notes are generated from the pull requests merged
+# since the previous release of the same series: the highest <prefix>X.Y.Z tag below the version,
+# where <prefix> is whatever precedes the version number (v in v1.2.3, nothing in 1.2.3). Without
+# it, GitHub would start from its latest release, which can be one of another series, such as a
+# chart release (<chart>-X.Y.Z) of the same repository.
 #
 # Environment:
 #   VERSION     tag and name of the release (required)
@@ -12,6 +16,8 @@
 #   TITLE       title of the release (default: VERSION)
 #   FILES       newline- or space-separated globs of the files to attach, relative to the current
 #               directory; a glob that matches nothing fails
+#   NOTES_START_TAG  tag the release notes start from (default: the previous release, see above;
+#               none when there is no previous one)
 #   REPOSITORY  owner/repo (default: $GITHUB_REPOSITORY)
 #   GH          gh binary (default: gh)
 
@@ -70,7 +76,34 @@ if [ "$release_exists" = true ] || [ "$tag_exists" = true ]; then
     fi
 fi
 
+# previous_release <version>: the highest <prefix>X.Y.Z tag of the repository below the X.Y.Z of the
+# version, or nothing
+previous_release() {
+    local version=$1 prefix number
+    prefix="${version%%[0-9]*}"
+    number="${version#"$prefix"}"
+    number="${number%%[-+]*}"
+    "$GH" api --paginate "repos/$REPOSITORY/tags" --jq '.[].name' \
+        | while IFS= read -r tag; do
+            case "$tag" in "$prefix"*) ;; *) continue ;; esac
+            candidate="${tag#"$prefix"}"
+            [[ "$candidate" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]] || continue
+            # keep the candidates below the version
+            if [ "$(printf '%s\n%s\n' "$candidate" "$number" | sort -t. -k1,1n -k2,2n -k3,3n | head -n 1)" = "$candidate" ] \
+                && [ "$candidate" != "$number" ]; then
+                echo "$candidate"
+            fi
+        done \
+        | sort -t. -k1,1n -k2,2n -k3,3n | tail -n 1 | sed "s/^/$prefix/"
+}
+
+NOTES_START_TAG="${NOTES_START_TAG-$(previous_release "$VERSION")}"
+
 args=(release create "$VERSION" --repo "$REPOSITORY" --target "$TARGET" --title "$TITLE" --generate-notes)
+if [ -n "$NOTES_START_TAG" ]; then
+    echo "Release notes start from $NOTES_START_TAG"
+    args+=(--notes-start-tag "$NOTES_START_TAG")
+fi
 if [ "$PRERELEASE" = true ]; then
     args+=(--prerelease)
 fi

tests/github-release.bats

@@ -1,6 +1,6 @@
 #!/usr/bin/env bats
 # Tests for scripts/github-release.sh, with a fake gh. $EXISTING_RELEASE and $EXISTING_TAG name the
-# release and the tag the fake repository already has.
+# release and the tag the fake repository already has, and $TAGS lists all its tags.
 
 load helpers
 
@@ -11,6 +11,7 @@ setup() {
     fake_command gh
     cat > "$BATS_TEST_TMPDIR/gh.sh" <<'EOF'
 case "$1 $2" in
+    "api --paginate") printf '%s\n' ${TAGS:-} ;;
     "release view") [ "$3" = "${EXISTING_RELEASE:-}" ] || exit 1 ;;
     "api repos/owner/repo/git/ref/tags/"*) [ "${2##*/}" = "${EXISTING_TAG:-}" ] || exit 1 ;;
 esac
@@ -79,3 +80,36 @@ EOF
     PRERELEASE=yes run "$SCRIPT"
     [ "$status" -eq 1 ]
 }
+
+@test "the notes start from the previous release of the same series, not from another series" {
+    TAGS="1.0.0 0.9.0 1.0.1-PRE-45 decentralized-iam-2.1.30 1.1.0" VERSION=1.0.1-PRE-45 PRERELEASE=true run "$SCRIPT"
+    [ "$status" -eq 0 ]
+    [[ "$output" == *"Release notes start from 1.0.0"* ]]
+    grep -q "release create 1.0.1-PRE-45 .* --notes-start-tag 1.0.0" "$BATS_TEST_TMPDIR/gh.log"
+}
+
+@test "a release takes the previous release as start, numerically" {
+    TAGS="11.9.0 11.39.0 11.38.1-PRE-3 11.4.0" VERSION=11.39.1 run "$SCRIPT"
+    [ "$status" -eq 0 ]
+    grep -q -- "--notes-start-tag 11.39.0$" "$BATS_TEST_TMPDIR/gh.log"
+}
+
+@test "a prefixed version only looks at the tags with its prefix" {
+    TAGS="v1.1.2 v1 1.5.0 v1.2.0" VERSION=v1.2.1 run "$SCRIPT"
+    [ "$status" -eq 0 ]
+    grep -q -- "--notes-start-tag v1.2.0$" "$BATS_TEST_TMPDIR/gh.log"
+}
+
+@test "without a previous release the notes have no start tag" {
+    TAGS="decentralized-iam-2.1.30 1.0.1-PRE-45" VERSION=1.0.0 run "$SCRIPT"
+    [ "$status" -eq 0 ]
+    ! grep -q -- "--notes-start-tag" "$BATS_TEST_TMPDIR/gh.log"
+}
+
+@test "NOTES_START_TAG overrides the previous release, and empty disables it" {
+    TAGS="1.0.0" NOTES_START_TAG=0.5.0 VERSION=1.0.1 run "$SCRIPT"
+    grep -q -- "--notes-start-tag 0.5.0$" "$BATS_TEST_TMPDIR/gh.log"
+    : > "$BATS_TEST_TMPDIR/gh.log"
+    TAGS="1.0.0" NOTES_START_TAG="" VERSION=1.0.1 run "$SCRIPT"
+    ! grep -q -- "--notes-start-tag" "$BATS_TEST_TMPDIR/gh.log"
+}