Merge pull request #12 from implausible/feature/proper-merge-message-handling

Give access to merge messages before they're utilized

Author: smith-kyle

src/Feature.js

@@ -70,7 +70,7 @@ class Feature {
    * @return {Commit}   The commit created by finishing the feature
    */
   static finishFeature(repo, featureName, options = {}) {
-    const {keepBranch, isRebase} = options;
+    const {keepBranch, isRebase, processMergeMessageCallback} = options;
 
     if (!repo) {
       return Promise.reject(new Error('Repo is required'));
@@ -113,7 +113,7 @@ class Feature {
         cancelDevelopMerge = isSameCommit || isRebase;
 
         if (!cancelDevelopMerge) {
-          return utils.Repo.merge(developBranch, featureBranch, repo);
+          return utils.Repo.merge(developBranch, featureBranch, repo, processMergeMessageCallback);
         } else if (isRebase && !isSameCommit) {
           return utils.Repo.rebase(developBranch, featureBranch, repo);
         }

src/Hotfix.js

@@ -63,7 +63,7 @@ class Hotfix {
    * @return {Commit}   The commit created by finishing the hotfix
    */
   static finishHotfix(repo, hotfixVersion, options = {}) {
-    const {keepBranch, message} = options;
+    const {keepBranch, message, processMergeMessageCallback} = options;
 
     if (!repo) {
       return Promise.reject(new Error('Repo is required'));
@@ -116,7 +116,7 @@ class Hotfix {
 
         // Merge hotfix into develop
         if (!cancelDevelopMerge) {
-          return utils.Repo.merge(developBranch, hotfixBranch, repo);
+          return utils.Repo.merge(developBranch, hotfixBranch, repo, processMergeMessageCallback);
         }
         return Promise.resolve();
       })
@@ -126,7 +126,7 @@ class Hotfix {
         const tagName = versionPrefix + hotfixVersion;
         // Merge the hotfix branch into master
         if (!cancelMasterMerge) {
-          return utils.Repo.merge(masterBranch, hotfixBranch, repo)
+          return utils.Repo.merge(masterBranch, hotfixBranch, repo, processMergeMessageCallback)
             .then((oid) => utils.Tag.create(oid, tagName, message, repo));
         }
 

src/Release.js

@@ -70,7 +70,7 @@ class Release {
    * @return {Commit}   The commit created by finishing the release
    */
   static finishRelease(repo, releaseVersion, options = {}) {
-    const {keepBranch, message} = options;
+    const {keepBranch, message, processMergeMessageCallback} = options;
 
     if (!repo) {
       return Promise.reject(new Error('Repo is required'));
@@ -123,7 +123,7 @@ class Release {
 
         // Merge release into develop
         if (!cancelDevelopMerge) {
-          return utils.Repo.merge(developBranch, releaseBranch, repo);
+          return utils.Repo.merge(developBranch, releaseBranch, repo, processMergeMessageCallback);
         }
         return Promise.resolve();
       })
@@ -133,7 +133,7 @@ class Release {
         const tagName = versionPrefix + releaseVersion;
         // Merge the release branch into master
         if (!cancelMasterMerge) {
-          return utils.Repo.merge(masterBranch, releaseBranch, repo)
+          return utils.Repo.merge(masterBranch, releaseBranch, repo, processMergeMessageCallback)
             .then((oid) => utils.Tag.create(oid, tagName, message, repo));
         }
 

src/utils/MergeUtils.js

@@ -1,6 +1,20 @@
 const MergeUtils = {
   getMergeMessage(toBranch, fromBranch) {
-    return `Merged ${fromBranch.shorthand()} into ${toBranch.shorthand()}`;
+    let mergeDecorator;
+    if (fromBranch.isTag()) {
+      mergeDecorator = 'tag';
+    } else if (fromBranch.isRemote()) {
+      mergeDecorator = 'remote-tracking branch';
+    } else {
+      mergeDecorator = 'branch';
+    }
+
+    const message = `Merge ${mergeDecorator} '${fromBranch.shorthand()}'`;
+
+    // https://github.com/git/git/blob/master/builtin/fmt-merge-msg.c#L456-L459
+    return toBranch.shorthand() !== 'master'
+      ? `${message} into ${toBranch.shorthand()}`
+      : message;
   }
 };
 

src/utils/RepoUtils.js

@@ -3,8 +3,7 @@ const NodeGit = require('nodegit');
 const MergeUtils = require('./MergeUtils');
 
 const RepoUtils = {
-  merge(toBranch, fromBranch, repo) {
-    let treeOid;
+  merge(toBranch, fromBranch, repo, processMergeMessageCallback = a => a) {
     return Promise.resolve()
       .then(() => {
         if (!toBranch.isHead()) {
@@ -27,20 +26,16 @@ const RepoUtils = {
 
         return index.writeTree();
       })
-      .then((oid) => {
-        treeOid = oid;
-
-        return Promise.all([
-          repo.getHeadCommit(),
-          repo.getBranchCommit('MERGE_HEAD')
-        ]);
-      })
-      .then((commits) => {
-        const signature = repo.defaultSignature();
-        const message = MergeUtils.getMergeMessage(toBranch, fromBranch);
-
-        return repo.createCommit('HEAD', signature, signature, message, treeOid, commits);
-      })
+      .then((treeOid) => Promise.all([
+        treeOid,
+        processMergeMessageCallback(MergeUtils.getMergeMessage(toBranch, fromBranch)),
+        repo.defaultSignature(),
+        repo.getHeadCommit(),
+        repo.getBranchCommit('MERGE_HEAD')
+      ]))
+      .then(([treeOid, message, signature, ...commits]) =>
+        repo.createCommit('HEAD', signature, signature, message, treeOid, commits)
+      )
       .then((commitId) => {
         repo.stateCleanup();