Improve version comparison to handle both X.Y.0 and X.Y.Z formats

- Compare major.minor versions instead of exact string match
- Preserve go directive if already at latest major.minor
- Handle cases where go.mod has full patch version (e.g., 1.25.6)
- Update PR body to use actual go directive from modified go.mod
- Add detailed comments explaining version handling logic

Co-authored-by: williammartin <1611510+williammartin@users.noreply.github.com>

.github/workflows/scripts/bump-go.sh

@@ -40,17 +40,19 @@ echo "Fetching latest stable Go version…"
 LATEST_JSON=$(curl -fsSL https://go.dev/dl/?mode=json | jq -c '[.[] | select(.stable==true)][0]')
 FULL_VERSION=$(jq -r '.version' <<< "$LATEST_JSON")        # e.g. go1.23.4
 TOOLCHAIN_VERSION="${FULL_VERSION#go}"                     # e.g. 1.23.4
-# `go mod tidy` will always add `.0` if there is no minor version
-# so let's just ensure .0 is suffixed to the go directive.
-GO_DIRECTIVE_VERSION="$(cut -d. -f1-2 <<< "$TOOLCHAIN_VERSION").0"
 
-echo "  → go : $GO_DIRECTIVE_VERSION"
-echo "  → toolchain : $TOOLCHAIN_VERSION"
+# The go directive can be either X.Y.0 (minor version) or X.Y.Z (patch version)
+# We accept both forms as "latest" if they match the toolchain's major.minor
+LATEST_MAJOR_MINOR="$(cut -d. -f1-2 <<< "$TOOLCHAIN_VERSION")"
+
+echo "  → latest toolchain : $TOOLCHAIN_VERSION"
 
 # ---- Prepare Git branch ---------------------------------------------------
 CURRENT_GO_DIRECTIVE=$(grep -E '^go ' "$GO_MOD" | cut -d ' ' -f2)
 CURRENT_TOOLCHAIN_DIRECTIVE=$(grep -E '^toolchain ' "$GO_MOD" | cut -d ' ' -f2 || true)
 
+CURRENT_MAJOR_MINOR="$(cut -d. -f1-2 <<< "$CURRENT_GO_DIRECTIVE")"
+
 BRANCH="bump-go-$TOOLCHAIN_VERSION"
 BRANCH_CREATED=0
 
@@ -64,19 +66,21 @@ cleanup() {
 trap cleanup EXIT
 
 # Check if we're already up to date
-# Note: toolchain directive may be missing when go directive == latest toolchain.
+# Note: toolchain directive may be missing when go directive >= latest toolchain.
 # This is expected behavior - `go mod tidy` removes the toolchain line when
-# the minimum Go version matches the latest toolchain, as it's redundant.
-if [[ "$CURRENT_GO_DIRECTIVE" = "$GO_DIRECTIVE_VERSION" ]]; then
+# the minimum Go version matches or exceeds the latest toolchain, as it's redundant.
+if [[ "$CURRENT_MAJOR_MINOR" = "$LATEST_MAJOR_MINOR" ]]; then
+  # Current go directive is at the same major.minor as latest
   if [[ -z "$CURRENT_TOOLCHAIN_DIRECTIVE" ]]; then
-    # No toolchain directive present - this is expected when go version == latest
-    echo "Already on latest Go version: $CURRENT_GO_DIRECTIVE"
+    # No toolchain directive present - this is expected when go version >= latest
+    echo "Already on latest Go version: $CURRENT_GO_DIRECTIVE (latest toolchain: $TOOLCHAIN_VERSION)"
     echo "  → Note: No toolchain directive (expected when go version matches latest toolchain)"
     exit 0
   elif [[ "$CURRENT_TOOLCHAIN_DIRECTIVE" = "go$TOOLCHAIN_VERSION" ]]; then
     echo "Already on latest Go version: $CURRENT_GO_DIRECTIVE (toolchain: $CURRENT_TOOLCHAIN_DIRECTIVE)"
     exit 0
   fi
+  # Current go directive is latest but toolchain is outdated - continue to update toolchain
 fi
 
 echo "Creating branch $BRANCH"
@@ -84,16 +88,22 @@ git switch -c "$BRANCH" >/dev/null 2>&1
 BRANCH_CREATED=1
 
 # ---- Patch go.mod -----------------------------------------------------------
-if [[ "$CURRENT_GO_DIRECTIVE" != "$GO_DIRECTIVE_VERSION" ]]; then
-  sed -Ei.bak "s/^go [0-9]+\.[0-9]+.*$/go $GO_DIRECTIVE_VERSION/" "$GO_MOD"
-  echo "  • go directive $CURRENT_GO_DIRECTIVE → $GO_DIRECTIVE_VERSION"
+# Only update go directive if we're not already at the latest major.minor version
+if [[ "$CURRENT_MAJOR_MINOR" != "$LATEST_MAJOR_MINOR" ]]; then
+  # Bump to the latest major.minor.0 (preserves the convention of X.Y.0 for go directive)
+  NEW_GO_DIRECTIVE="$LATEST_MAJOR_MINOR.0"
+  sed -Ei.bak "s/^go [0-9]+\.[0-9]+.*$/go $NEW_GO_DIRECTIVE/" "$GO_MOD"
+  echo "  • go directive $CURRENT_GO_DIRECTIVE → $NEW_GO_DIRECTIVE"
+  # After updating, the current go directive is now the new one for toolchain logic
+  CURRENT_GO_DIRECTIVE="$NEW_GO_DIRECTIVE"
 fi
 
 # Handle toolchain directive - may need to add, update, or skip
 if [[ -z "$CURRENT_TOOLCHAIN_DIRECTIVE" ]]; then
   # No toolchain directive exists
-  if [[ "$GO_DIRECTIVE_VERSION" = "$(cut -d. -f1-2 <<< "$TOOLCHAIN_VERSION").0" ]]; then
-    # go directive matches latest toolchain - toolchain line is redundant
+  CURRENT_MAJOR_MINOR="$(cut -d. -f1-2 <<< "$CURRENT_GO_DIRECTIVE")"
+  if [[ "$CURRENT_MAJOR_MINOR" = "$LATEST_MAJOR_MINOR" ]]; then
+    # go directive is at latest major.minor - toolchain line is redundant
     echo "  • toolchain directive not needed (go version matches latest toolchain)"
   else
     # go directive is older than latest toolchain - add toolchain directive after go line
@@ -139,10 +149,13 @@ if [[ $APPLY -eq 0 ]]; then
 fi
 
 # ---- Push & PR --------------------------------------------------------------
+# Get the actual go directive from the updated go.mod
+FINAL_GO_DIRECTIVE=$(grep -E '^go ' "$GO_MOD" | cut -d ' ' -f2)
+
 PR_BODY=$(cat <<EOF
 This PR updates Go to the latest stable release.
 
-* **go directive:** \`$GO_DIRECTIVE_VERSION\`
+* **go directive:** \`$FINAL_GO_DIRECTIVE\`
 * **toolchain:** \`$TOOLCHAIN_VERSION\`
 EOF
 )