Fix CalVer enforcement running on semver-only releases

[juanpprieto]

WHY are these changes introduced?

Related to #3233

When merging changesets for only semver packages (cli-hydrogen, mini-oxygen, create-hydrogen), the CalVer enforcement script ran unconditionally and created phantom version bumps for CalVer packages (hydrogen, hydrogen-react, skeleton). This forced maintainers to manually revert changeset commits.

The script checked for changeset files that had already been deleted by changeset version, causing it to skip enforcement for ALL releases including legitimate CalVer releases.

WHAT is this pull request doing?

Primary fix: Guard check now compares actual version changes instead of checking for deleted changeset files.

Additional improvements:

• Enables independent patch versioning for CalVer packages
• Keeps major versions synchronized across all CalVer packages
• Makes CI tests dynamic instead of hardcoded for specific quarters

Change	File	Impact
Version comparison guard	.changeset/enforce-calver-ci.js	Skips when no CalVer changes, runs when CalVer packages bumped
Independent patches	.changeset/enforce-calver-ci.js	CalVer packages can have different patch versions
Synced majors	.changeset/enforce-calver-ci.js	All CalVer packages advance to same quarter for majors
Dynamic test expectations	.github/workflows/test-calver.yml	Tests work for any quarter, any year
Full pipeline test	.github/workflows/test-calver.yml	Test 8 validates complete version script flow
Documentation	docs/CALVER.md	Documents independent patches behavior

Before:

npm run version:changeset (bumps CLI)
   ↓
enforce-calver-ci.js checks for .md files (deleted)
   ↓
Skips for ALL releases
   ↓
CalVer releases broken, semver creates phantom bumps

After:

npm run version:changeset
   ↓
enforce-calver-ci.js compares versions
   ↓
No CalVer changes → Skip (semver-only)
CalVer changed → Run enforcement
   ↓
Patches: Independent
Majors: Synced to same quarter

HOW to test your changes?

Verify semver-only skips CalVer enforcement

cat > .changeset/test-cli.md << 'EOF'
---
'@shopify/cli-hydrogen': patch
---
Test
EOF

npm run version:changeset
node .changeset/enforce-calver-ci.js
# Expected: "No CalVer package changes detected. Skipping CalVer enforcement."

# Verify
node -p "require('./packages/hydrogen/package.json').version"  # 2025.7.0 (unchanged)

git restore .

Verify CalVer releases run enforcement

cat > .changeset/test-hydrogen.md << 'EOF'
---
'@shopify/hydrogen': patch
---
Test
EOF

npm run version:changeset
node .changeset/enforce-calver-ci.js
# Expected: "Starting CalVer enforcement..."

# Verify
node -p "require('./packages/hydrogen/package.json').version"  # 2025.7.1 (bumped)

git restore .

Verify independent patches

cat > .changeset/test-skeleton.md << 'EOF'
---
'skeleton': patch
---
Test
EOF

npm run version:changeset
node .changeset/enforce-calver-ci.js

# Verify only skeleton changed
node -p "require('./packages/hydrogen/package.json').version"  # 2025.7.0
node -p "require('./templates/skeleton/package.json').version"  # 2025.7.1

git restore .

Verify synced majors

cat > .changeset/test-major.md << 'EOF'
---
'@shopify/hydrogen': major
---
Test
EOF

npm run version:changeset
node .changeset/enforce-calver-ci.js

# Verify all synced
node -p "require('./packages/hydrogen/package.json').version"  # 2025.10.0
node -p "require('./packages/hydrogen-react/package.json').version"  # 2025.10.0
node -p "require('./templates/skeleton/package.json').version"  # 2025.10.0

git restore .

Checklist

• I've read the Contributing Guidelines
• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've added a changeset if this PR contains user-facing or noteworthy changes
• I've added tests to cover my changes
• I've added or updated the documentation

[shopify]

Oxygen deployed a preview of your juanpprieto/fix-calver-semver-only branch. Details:

Storefront	Status	Preview link	Deployment details	Last update (UTC)
Skeleton (skeleton.hydrogen.shop)	✅ Successful (Logs)	Preview deployment	Inspect deployment	October 2, 2025 3:47 AM

Learn more about Hydrogen's GitHub integration.