feat: smartly generate changelog from previous stable release

src/config.ts

@@ -1,4 +1,4 @@
-import { getCurrentGitBranch, getFirstGitCommit, getGitHubRepo, getLastGitTag, isPrerelease } from './git'
+import { getCurrentGitBranch, getFirstGitCommit, getGitHubRepo, getLastMatchingTag, isPrerelease } from './git'
 import type { ChangelogOptions, ResolvedChangelogOptions } from './types'
 
 export function defineConfig(config: ChangelogOptions) {
@@ -28,18 +28,14 @@ export async function resolveConfig(options: ChangelogOptions) {
     overrides: options,
   }).then(r => r.config || defaultConfig)
 
-  config.from = config.from || await getLastGitTag()
   config.to = config.to || await getCurrentGitBranch()
+  config.from = config.from || await getLastMatchingTag(config.to) || await getFirstGitCommit()
   // @ts-expect-error backward compatibility
   config.repo = config.repo || config.github || await getGitHubRepo()
+  config.prerelease = config.prerelease ?? isPrerelease(config.to)
 
   if (typeof config.repo !== 'string')
     throw new Error(`Invalid GitHub repository, expected a string but got ${JSON.stringify(config.repo)}`)
 
-  config.prerelease = config.prerelease ?? isPrerelease(config.to)
-
-  if (config.to === config.from)
-    config.from = await getLastGitTag(-1) || await getFirstGitCommit()
-
   return config as ResolvedChangelogOptions
 }

src/git.ts

@@ -14,9 +14,25 @@ export async function isRepoShallow() {
   return (await execCommand('git', ['rev-parse', '--is-shallow-repository'])).trim() === 'true'
 }
 
-export async function getLastGitTag(delta = 0) {
-  const tags = await execCommand('git', ['--no-pager', 'tag', '-l', '--sort=creatordate']).then(r => r.split('\n'))
-  return tags[tags.length + delta - 1]
+export async function getGitTags() {
+  return (await execCommand('git', ['--no-pager', 'tag', '-l', '--sort=creatordate']).then(r => r.split('\n')))
+    .reverse()
+}
+
+export async function getLastMatchingTag(inputTag: string) {
+  const isVersion = inputTag[0] === 'v'
+  const isPrerelease = inputTag[0] === 'v' && inputTag.includes('-')
+  const tags = await getGitTags()
+
+  let tag: string | undefined
+  // Doing a stable release, find the last stable release to compare with
+  if (!isPrerelease && isVersion)
+    tag = tags.find(tag => tag !== inputTag && tag[0] === 'v' && !tag.includes('-'))
+
+  // Fallback to the last tag, that are not the input tag
+  tag ||= tags.find(tag => tag !== inputTag)
+
+  return tag
 }
 
 export async function isRefGitTag(to: string) {