If the update-type is missing for some reason, calculate it

src/dependabot/update_metadata.test.ts

@@ -30,7 +30,6 @@ test('it returns the updated dependency information when there is a yaml fragmen
     'updated-dependencies:\n' +
     '- dependency-name: coffee-rails\n' +
     '  dependency-type: direct:production\n' +
-    '  update-type: version-update:semver-minor\n' +
     '...\n' +
     '\n' +
     'Signed-off-by: dependabot[bot] <support@github.com>'
@@ -194,3 +193,19 @@ test('it properly handles dependencies which contain slashes', async () => {
   expect(updatedDependencies[0].ghsaId).toEqual('')
   expect(updatedDependencies[0].cvss).toEqual(0)
 })
+
+test('calculateUpdateType should handle all paths', () => {
+  expect(updateMetadata.calculateUpdateType('', '')).toEqual('')
+  expect(updateMetadata.calculateUpdateType('', '1')).toEqual('')
+  expect(updateMetadata.calculateUpdateType('1', '')).toEqual('')
+  expect(updateMetadata.calculateUpdateType('1.1.1', '1.1.1')).toEqual('')
+  expect(updateMetadata.calculateUpdateType('1', '2')).toEqual('version-update:semver-major')
+  expect(updateMetadata.calculateUpdateType('1.2.2', '2.2.2')).toEqual('version-update:semver-major')
+  expect(updateMetadata.calculateUpdateType('1.1', '1')).toEqual('version-update:semver-minor')
+  expect(updateMetadata.calculateUpdateType('1', '1.1')).toEqual('version-update:semver-minor')
+  expect(updateMetadata.calculateUpdateType('1.2.1', '1.1.1')).toEqual('version-update:semver-minor')
+  expect(updateMetadata.calculateUpdateType('1.1.1', '1.1')).toEqual('version-update:semver-patch')
+  expect(updateMetadata.calculateUpdateType('1.1', '1.1.1')).toEqual('version-update:semver-patch')
+  expect(updateMetadata.calculateUpdateType('1.1.1', '1.1.2')).toEqual('version-update:semver-patch')
+  expect(updateMetadata.calculateUpdateType('1.1.1.1', '1.1.1.2')).toEqual('version-update:semver-patch')
+})

src/dependabot/update_metadata.ts

@@ -46,10 +46,11 @@ export async function parse (commitMessage: string, branchName: string, mainBran
         const dirname = `/${chunks.slice(2, -1 * (1 + (dependency['dependency-name'].match(/\//g) || []).length)).join(delim) || ''}`
         const lastVersion = index === 0 ? prev : ''
         const nextVersion = index === 0 ? next : ''
+        const updateType = dependency['update-type'] || calculateUpdateType(lastVersion, nextVersion)
         return {
           dependencyName: dependency['dependency-name'],
           dependencyType: dependency['dependency-type'],
-          updateType: dependency['update-type'],
+          updateType: updateType,
           directory: dirname,
           packageEcosystem: chunks[1],
           targetBranch: mainBranch,
@@ -64,3 +65,22 @@ export async function parse (commitMessage: string, branchName: string, mainBran
 
   return Promise.resolve([])
 }
+
+export function calculateUpdateType (lastVersion: string, nextVersion: string) {
+  if (!lastVersion || !nextVersion || lastVersion === nextVersion) {
+    return ''
+  }
+
+  const lastParts = lastVersion.split('.')
+  const nextParts = nextVersion.split('.')
+
+  if (lastParts[0] !== nextParts[0]) {
+    return 'version-update:semver-major'
+  }
+
+  if (lastParts.length < 2 || nextParts.length < 2 || lastParts[1] !== nextParts[1]) {
+    return 'version-update:semver-minor'
+  }
+
+  return 'version-update:semver-patch'
+}