✨ Add option to use original commit message (#96)

Fixes discussion #13

README.md

@@ -108,6 +108,7 @@ Here are all the inputs [repo-file-sync-action](https://github.com/BetaHuhn/repo
 | `ASSIGNEES` | People to assign to the pull request | **No** | N/A |
 | `COMMIT_PREFIX` | Prefix for commit message and pull request title | **No** | 🔄 |
 | `COMMIT_BODY` | Commit message body. Will be appended to commit message, separated by two line returns. | **No** | '' |
+| `ORIGINAL_MESSAGE` | Use original commit message instead. Only works if the file(s) where changed and the action was triggered by pushing a single commit. | **No** | false |
 | `COMMIT_EACH_FILE` | Commit each file seperately | **No** | true |
 | `GIT_EMAIL` | The e-mail address used to commit the synced files | **Only when using installation token** | the email of the PAT used |
 | `GIT_USERNAME` | The username used to commit the synced files | **Only when using installation token** | the username of the PAT used |

action.yml

@@ -63,6 +63,10 @@ inputs:
     description: |
       Overwrite any existing Sync PR with the new changes. Defaults to true
     required: false
+  ORIGINAL_MESSAGE:
+    description: |
+      Re-use the original commit message for commits. Works only if the action is triggered by pushing one commit. Defaults to false
+    required: false
   SKIP_PR:
     description: |
       Skips creating a Pull Request and pushes directly to the default branch. Defaults to false

src/config.js

@@ -95,6 +95,11 @@ try {
 			type: 'boolean',
 			default: false
 		}),
+		ORIGINAL_MESSAGE: getInput({
+			key: 'ORIGINAL_MESSAGE',
+			type: 'boolean',
+			default: false
+		}),
 		BRANCH_PREFIX: getInput({
 			key: 'BRANCH_PREFIX',
 			default: 'repo-sync/SOURCE_REPO_NAME'

src/git.js

@@ -1,5 +1,6 @@
 const { parse } = require('@putout/git-status-porcelain')
 const core = require('@actions/core')
+const github = require('@actions/github')
 const { GitHub, getOctokitOptions } = require('@actions/github/lib/utils')
 const { throttling } = require('@octokit/plugin-throttling')
 const path = require('path')
@@ -127,6 +128,58 @@ class Git {
 		)
 	}
 
+	isOneCommitPush() {
+		return github.context.eventName === 'push' && github.context.payload.commits.length === 1
+	}
+
+	originalCommitMessage() {
+		return github.context.payload.commits[0].message
+	}
+
+	parseGitDiffOutput(string) { // parses git diff output and returns a dictionary mapping the file path to the diff output for this file
+		// split diff into separate entries for separate files. \ndiff --git should be a reliable way to detect the separation, as content of files is always indented
+		return `\n${ string }`.split('\ndiff --git').slice(1).reduce((resultDict, fileDiff) => {
+			const lines = fileDiff.split('\n')
+			const lastHeaderLineIndex = lines.findIndex((line) => line.startsWith('+++'))
+			const plainDiff = lines.slice(lastHeaderLineIndex + 1).join('\n').trim()
+			let filePath = ''
+			if (lines[lastHeaderLineIndex].startsWith('+++ b/')) { // every file except removed files
+				filePath = lines[lastHeaderLineIndex].slice(6) // remove '+++ b/'
+			} else { // for removed file need to use header line with filename before deletion
+				filePath = lines[lastHeaderLineIndex - 1].slice(6) // remove '--- a/'
+			}
+			return { ...resultDict, [filePath]: plainDiff }
+		}, {})
+	}
+
+	async getChangesFromLastCommit(source) { // gets array of git diffs for the source, which either can be a file or a dict
+		if (this.lastCommitChanges === undefined) {
+			const diff = await this.github.repos.compareCommits({
+				mediaType: {
+					format: 'diff'
+				},
+				owner: github.context.payload.repository.owner.name,
+				repo: github.context.payload.repository.name,
+				base: github.context.payload.before,
+				head: github.context.payload.after
+			})
+			this.lastCommitChanges = this.parseGitDiffOutput(diff.data)
+		}
+		if (source.endsWith('/')) {
+			return Object.keys(this.lastCommitChanges).filter((filePath) => filePath.startsWith(source)).reduce((result, key) => [ ...result, this.lastCommitChanges[key] ], [])
+		} else {
+			return this.lastCommitChanges[source] === undefined ? [] : [ this.lastCommitChanges[source] ]
+		}
+	}
+
+	async changes(destination) { // gets array of git diffs for the destination, which either can be a file or a dict
+		const output = await execCmd(
+			`git diff HEAD ${ destination }`,
+			this.workingDir
+		)
+		return Object.values(this.parseGitDiffOutput(output))
+	}
+
 	async hasChanges() {
 		const statusOutput = await execCmd(
 			`git status --porcelain`,
@@ -142,7 +195,7 @@ class Git {
 			message += `\n\n${ COMMIT_BODY }`
 		}
 		return execCmd(
-			`git commit -m "${ message }"`,
+			`git commit -m "${ message.replace(/"/g, '\\"') }"`,
 			this.workingDir
 		)
 	}

src/helpers.js

@@ -98,12 +98,15 @@ const remove = async (src) => {
 	return fs.remove(src)
 }
 
+const arrayEquals = (array1, array2) => Array.isArray(array1) && Array.isArray(array2) && array1.length === array2.length && array1.every((value, i) => value === array2[i])
+
 module.exports = {
 	forEach,
 	dedent,
 	addTrailingSlash,
 	pathIsDirectory,
 	execCmd,
 	copy,
-	remove
+	remove,
+	arrayEquals
 }

src/index.js

@@ -2,7 +2,7 @@ const core = require('@actions/core')
 const fs = require('fs')
 
 const Git = require('./git')
-const { forEach, dedent, addTrailingSlash, pathIsDirectory, copy, remove } = require('./helpers')
+const { forEach, dedent, addTrailingSlash, pathIsDirectory, copy, remove, arrayEquals } = require('./helpers')
 
 const {
 	parseConfig,
@@ -14,7 +14,8 @@ const {
 	TMP_DIR,
 	SKIP_CLEANUP,
 	OVERWRITE_EXISTING_PR,
-	SKIP_PR
+	SKIP_PR,
+	ORIGINAL_MESSAGE
 } = require('./config')
 
 const run = async () => {
@@ -82,14 +83,15 @@ const run = async () => {
 					// Use different commit/pr message based on if the source is a directory or file
 					const directory = isDirectory ? 'directory' : ''
 					const otherFiles = isDirectory ? 'and copied all sub files/folders' : ''
+					const useOriginalCommitMessage = ORIGINAL_MESSAGE && git.isOneCommitPush() && arrayEquals(await git.getChangesFromLastCommit(file.source), await git.changes(file.dest))
 
 					const message = {
 						true: {
-							commit: `${ COMMIT_PREFIX } Synced local '${ file.dest }' with remote '${ file.source }'`,
+							commit: useOriginalCommitMessage ? git.originalCommitMessage() : `${ COMMIT_PREFIX } Synced local '${ file.dest }' with remote '${ file.source }'`,
 							pr: `Synced local ${ directory } <code>${ file.dest }</code> with remote ${ directory } <code>${ file.source }</code>`
 						},
 						false: {
-							commit: `${ COMMIT_PREFIX } Created local '${ file.dest }' from remote '${ file.source }'`,
+							commit: useOriginalCommitMessage ? git.originalCommitMessage() : `${ COMMIT_PREFIX } Created local '${ file.dest }' from remote '${ file.source }'`,
 							pr: `Created local ${ directory } <code>${ file.dest }</code> ${ otherFiles } from remote ${ directory } <code>${ file.source }</code>`
 						}
 					}
@@ -128,7 +130,14 @@ const run = async () => {
 			if (hasChanges === true) {
 				core.debug(`Creating commit for remaining files`)
 
-				await git.commit()
+				let useOriginalCommitMessage = ORIGINAL_MESSAGE && git.isOneCommitPush()
+				if (useOriginalCommitMessage) {
+					await forEach(item.files, async (file) => {
+						useOriginalCommitMessage = useOriginalCommitMessage && arrayEquals(await git.getChangesFromLastCommit(file.source), await git.changes(file.dest))
+					})
+				}
+
+				await git.commit(useOriginalCommitMessage ? git.originalCommitMessage() : undefined)
 				modified.push({
 					dest: git.workingDir
 				})