- introduce better more stable fallbacks in case the configuration is missing

- move configurations into subfolder for easier discovery
- simplify missing value fallback specification

src/main.ts

@@ -4,6 +4,7 @@ import {ReleaseNotes} from './releaseNotes'
 import {createCommandManager} from './git-helper'
 import * as github from '@actions/github'
 import * as path from 'path'
+import {DefaultConfiguration} from './configuration'
 
 async function run(): Promise<void> {
   try {
@@ -19,12 +20,22 @@ async function run(): Promise<void> {
     core.debug(`repositoryPath = '${repositoryPath}'`)
 
     const configurationFile: string = core.getInput('configuration')
-    const configurationPath = path.resolve(
-      githubWorkspacePath,
-      configurationFile
-    )
-    core.debug(`configurationPath = '${configurationPath}'`)
-    const configuration = readConfiguration(configurationPath)
+    let configuration = DefaultConfiguration
+    if (configurationFile) {
+      const configurationPath = path.resolve(
+        githubWorkspacePath,
+        configurationFile
+      )
+      core.debug(`configurationPath = '${configurationPath}'`)
+      const providedConfiguration = readConfiguration(configurationPath)
+      if (!providedConfiguration) {
+        core.error(
+          `Configuration provided, but it couldn't be found, or failed to parse`
+        )
+      } else {
+        configuration = providedConfiguration
+      }
+    }
 
     const token = core.getInput('token')
     let owner = core.getInput('owner')

src/releaseNotes.ts

@@ -1,5 +1,5 @@
 import {Octokit} from '@octokit/rest'
-import { Commits, CommitInfo } from './commits';
+import {Commits, CommitInfo} from './commits'
 import {PullRequestInfo, PullRequests} from './pullRequests'
 import {buildChangelog} from './transform'
 import * as core from '@actions/core'
@@ -34,17 +34,15 @@ export class ReleaseNotes {
         repo,
         toTag,
         ignorePreReleases,
-        configuration.max_tags_to_fetch
-          ? configuration.max_tags_to_fetch
-          : DefaultConfiguration.max_tags_to_fetch
+        configuration.max_tags_to_fetch ??
+          DefaultConfiguration.max_tags_to_fetch
       )
       if (previousTag == null) {
         core.error(`Unable to retrieve previous tag given ${toTag}`)
-        return configuration.empty_template
-          ? configuration.empty_template
-          : DefaultConfiguration.empty_template
+        return (
+          configuration.empty_template ?? DefaultConfiguration.empty_template
+        )
       }
-
       this.options.fromTag = previousTag.name
       core.debug(`fromTag resolved via previousTag as: ${previousTag.name}`)
     }
@@ -53,9 +51,7 @@ export class ReleaseNotes {
 
     if (mergedPullRequests.length === 0) {
       core.warning(`No pull requests found`)
-      return configuration.empty_template
-        ? configuration.empty_template
-        : DefaultConfiguration.empty_template
+      return configuration.empty_template ?? DefaultConfiguration.empty_template
     }
 
     return buildChangelog(mergedPullRequests, configuration)
@@ -85,9 +81,9 @@ export class ReleaseNotes {
     let fromDate = firstCommit.date
     const toDate = lastCommit.date
 
-    const maxDays = configuration.max_back_track_time_days
-      ? configuration.max_back_track_time_days
-      : DefaultConfiguration.max_back_track_time_days
+    const maxDays =
+      configuration.max_back_track_time_days ??
+      DefaultConfiguration.max_back_track_time_days
     const maxFromDate = toDate.clone().subtract(maxDays, 'days')
     if (maxFromDate.isAfter(fromDate)) {
       core.info(`Adjusted 'fromDate' to go max ${maxDays} back`)

src/utils.ts

@@ -1,8 +1,12 @@
 import * as fs from 'fs'
 import {Configuration} from './configuration'
 
-export function readConfiguration(filename: string): Configuration {
-  const rawdata = fs.readFileSync(filename, 'utf8')
-  const configurationJSON: Configuration = JSON.parse(rawdata)
-  return configurationJSON
+export function readConfiguration(filename: string): Configuration | null {
+  try {
+    const rawdata = fs.readFileSync(filename, 'utf8')
+    const configurationJSON: Configuration = JSON.parse(rawdata)
+    return configurationJSON
+  } catch (error) {
+    return null
+  }
 }