nodegit · implausible · Apr 9, 2018 · Apr 9, 2018
diff --git a/generate/input/descriptor.json b/generate/input/descriptor.json
@@ -524,7 +524,27 @@
           }
         },
         "git_commit_create_buffer": {
-          "ignore": true
+          "args": {
+            "out": {
+              "isReturn": true,
+              "cppClassName": "GitBuf",
+              "jsClassName": "Buffer",
+              "shouldAlloc": true
+            },
+            "message_encoding": {
+              "isOptional": true
+            },
+            "parents": {
+              "cType": "const git_commit **",
+              "cppClassName": "Array",
+              "jsClassName": "Array",
+              "arrayElementCppClassName": "GitCommit"
+            }
+          },
+          "isAsync": true,
+          "return": {
+            "isErrorCode": true
+          }
         },
         "git_commit_create_from_callback": {
           "ignore": true

diff --git a/lib/repository.js b/lib/repository.js
@@ -537,7 +537,7 @@ Repository.prototype.createBlobFromBuffer = function(buffer) {
  * @param {Signature} author
  * @param {Signature} committer
  * @param {String} message
- * @param {Tree|Oid|String} Tree
+ * @param {Oid|String} Tree
  * @param {Array} parents
  * @return {Oid} The oid of the commit
  */
@@ -586,6 +586,43 @@ Repository.prototype.createCommit = function(
   }, callback);
 };
 
+/**
+ * Create a commit
+ *
+ * @async
+ * @param {Signature} author
+ * @param {Signature} committer
+ * @param {String} message
+ * @param {Oid|String} treeOid
+ * @param {Array} parents
+ * @return {String} The content of the commit object
+ *                  as a string
+ */
+Repository.prototype.createCommitBuffer = function(
+  author, committer, message, treeOid, parents) {
+
+  const repo = this;
+  const promises = (parents || [])
+    .reduce(function(acc, parent) {
+      acc.push(repo.getCommit(parent));
+      return acc;
+    }, [repo.getTree(treeOid)]);
+
+  return Promise.all(promises)
+    .then(function([tree, ...parentCommits]) {
+      return Commit.createBuffer(
+        repo,
+        author,
+        committer,
+        null /* use default message encoding */,
+        message,
+        tree,
+        parentCommits.length,
+        parentCommits
+      );
+    });
+};
+
 /**
  * Creates a new commit on HEAD from the list of passed in files
  *

diff --git a/test/tests/commit.js b/test/tests/commit.js
@@ -199,6 +199,78 @@ describe("Commit", function() {
     });
   });
 
+  it("can create a commit as a buffer", function() {
+    var test = this;
+    var fileName = "newfile.txt";
+    var fileContent = "hello world";
+
+    const expectedCommitContent =
+      "tree 11c8685af551550e73e5ab89fa554576bd92ef3f\n" +
+      "parent 32789a79e71fbc9e04d3eff7425e1771eb595150\n" +
+      "author Foo Bar <foo@bar.com> 123456789 +0100\n" +
+      "committer Foo A Bar <foo@bar.com> 987654321 +0130\n\n" +
+      "message";
+
+    var repo;
+    var index;
+    var treeOid;
+    var parent;
+
+    return NodeGit.Repository.open(reposPath)
+    .then(function(repoResult) {
+      repo = repoResult;
+      return fse.writeFile(path.join(repo.workdir(), fileName), fileContent);
+    })
+    .then(function() {
+      return repo.refreshIndex();
+    })
+    .then(function(indexResult) {
+      index = indexResult;
+    })
+    .then(function() {
+      return index.addByPath(fileName);
+    })
+    .then(function() {
+      return index.write();
+    })
+    .then(function() {
+      return index.writeTree();
+    })
+    .then(function(oidResult) {
+      treeOid = oidResult;
+      return NodeGit.Reference.nameToId(repo, "HEAD");
+    })
+    .then(function(head) {
+      return repo.getCommit(head);
+    })
+    .then(function(parentResult) {
+      parent = parentResult;
+      return Promise.all([
+        NodeGit.Signature.create("Foo Bar", "foo@bar.com", 123456789, 60),
+        NodeGit.Signature.create("Foo A Bar", "foo@bar.com", 987654321, 90)
+      ]);
+    })
+    .then(function(signatures) {
+      var author = signatures[0];
+      var committer = signatures[1];
+
+      return repo.createCommitBuffer(
+        author,
+        committer,
+        "message",
+        treeOid,
+        [parent]);
+    })
+    .then(function(commitContent) {
+      assert.equal(expectedCommitContent, commitContent);
+      return reinitialize(test);
+    }, function(reason) {
+      return reinitialize(test)
+        .then(function() {
+          return Promise.reject(reason);
+        });
+    });
+  });
 
   it("can amend commit", function(){
     var commitToAmendId = "315e77328ef596f3bc065d8ac6dd2c72c09de8a5";