Fix --starting-version

The tags logic was removing the tag after the starting version passed in, so the diff logic became "grab all the commits from the start of the repo to the starting version" – this updates the logic to keep the previous tag to the starting version, so the diff for that version is accurate

Fixes #164

src/releases.js

@@ -37,6 +37,9 @@ async function createRelease (tag, previousTag, date, diff, remote, options, onP
 
 function parseReleases (tags, remote, latestVersion, options, onParsed) {
   const releases = tags.map(({ tag, date }, index, tags) => {
+    if (tags[index - 1] && tags[index - 1].tag === options.startingVersion) {
+      return null
+    }
     const previousTag = tags[index + 1] ? tags[index + 1].tag : null
     const diff = previousTag ? `${previousTag}..${tag}` : tag
     return createRelease(tag, previousTag, date, diff, remote, options, onParsed)
@@ -48,7 +51,7 @@ function parseReleases (tags, remote, latestVersion, options, onParsed) {
     const diff = `${previousTag}..`
     releases.unshift(createRelease(tag, previousTag, date, diff, remote, options, onParsed))
   }
-  return Promise.all(releases)
+  return Promise.all(releases.filter(release => release))
 }
 
 function getCommitLimit ({ commitLimit, backfillLimit }, emptyRelease, breakingCount) {

src/tags.js

@@ -13,7 +13,8 @@ async function fetchTags (options) {
   if (options.startingVersion) {
     const index = tags.findIndex(({ tag }) => tag === options.startingVersion)
     if (index !== -1) {
-      return tags.slice(0, index + 1)
+      // Leave the tag after the starting version for the diff
+      return tags.slice(0, index + 2)
     }
   }
   return tags

test/tags.js

@@ -36,7 +36,8 @@ describe('fetchTags', () => {
   it('supports --starting-version', async () => {
     expect(await fetchTags({ ...options, startingVersion: 'v0.3.0' })).to.deep.equal([
       { tag: 'v1.0.0', date: '2001-01-01' },
-      { tag: 'v0.3.0', date: '2000-04-01' }
+      { tag: 'v0.3.0', date: '2000-04-01' },
+      { tag: 'v0.2.2', date: '2000-03-03' }
     ])
   })
 })