Hide amend parent handling in signing helper

Author: kausters

GitUpKit/Core/GCCommitSigning.m

@@ -238,6 +238,7 @@ static BOOL _LooksLikeInlineSSHKey(NSString* key) {
   git_signature* signature = NULL;
   git_commit* newCommit = NULL;
   NSData* cleanedMessage = nil;
+  const char* cleanedMessageBytes = NULL;
 #if !TARGET_OS_IPHONE
   git_buf commitBuffer = {0};
   NSData* commitData = nil;
@@ -249,13 +250,14 @@ static BOOL _LooksLikeInlineSSHKey(NSString* key) {
   CALL_LIBGIT2_FUNCTION_GOTO(cleanup, git_signature_default, &signature, repository.private);
   authorSignature = author ?: signature;
   cleanedMessage = GCCleanedUpCommitMessage(message);
+  cleanedMessageBytes = (const char*)cleanedMessage.bytes;
 #if !TARGET_OS_IPHONE
   if (!_ShouldSSHSignCommit(repository, &shouldSign, error)) {
     goto cleanup;
   }
 
   if (shouldSign) {
-    CALL_LIBGIT2_FUNCTION_GOTO(cleanup, git_commit_create_buffer, &commitBuffer, repository.private, authorSignature, signature, NULL, cleanedMessage.bytes, tree, count, parents);
+    CALL_LIBGIT2_FUNCTION_GOTO(cleanup, git_commit_create_buffer, &commitBuffer, repository.private, authorSignature, signature, NULL, cleanedMessageBytes, tree, count, parents);
     commitData = [[NSData alloc] initWithBytes:commitBuffer.ptr length:commitBuffer.size];
     sshSignature = _SSHSignatureForCommitBuffer(repository, commitData, error);
     if (!sshSignature) {
@@ -264,7 +266,7 @@ static BOOL _LooksLikeInlineSSHKey(NSString* key) {
     CALL_LIBGIT2_FUNCTION_GOTO(cleanup, git_commit_create_with_signature, &oid, repository.private, commitBuffer.ptr, sshSignature.UTF8String, "gpgsig");
   } else {
 #endif
-    CALL_LIBGIT2_FUNCTION_GOTO(cleanup, git_commit_create, &oid, repository.private, NULL, authorSignature, signature, NULL, cleanedMessage.bytes, tree, count, parents);
+    CALL_LIBGIT2_FUNCTION_GOTO(cleanup, git_commit_create, &oid, repository.private, NULL, authorSignature, signature, NULL, cleanedMessageBytes, tree, count, parents);
 #if !TARGET_OS_IPHONE
   }
 #endif
@@ -280,3 +282,40 @@ static BOOL _LooksLikeInlineSSHKey(NSString* key) {
   git_signature_free(signature);
   return commit;
 }
+
+GCCommit* GCCreateCommitFromCommitWithIndexAndOptionalSignature(GCRepository* repository, git_commit* amendedCommit, git_index* index, NSString* message, NSError** error) {
+  GCCommit* commit = nil;
+  git_tree* tree = NULL;
+  git_commit** parentCommits = NULL;
+  unsigned int parentCount = 0;
+  const git_commit** parents = NULL;
+
+  git_oid oid;
+  CALL_LIBGIT2_FUNCTION_GOTO(cleanup, git_index_write_tree_to, &oid, index, repository.private);
+  CALL_LIBGIT2_FUNCTION_GOTO(cleanup, git_tree_lookup, &tree, repository.private, &oid);
+
+  parentCount = git_commit_parentcount(amendedCommit);
+  if (parentCount) {
+    parentCommits = (git_commit**)calloc(parentCount, sizeof(git_commit*));
+    if (!parentCommits) {
+      GC_SET_GENERIC_ERROR(@"Unable to allocate commit parent list");
+      goto cleanup;
+    }
+    for (unsigned int i = 0; i < parentCount; ++i) {
+      CALL_LIBGIT2_FUNCTION_GOTO(cleanup, git_commit_parent, &parentCommits[i], amendedCommit, i);
+    }
+  }
+  parents = (const git_commit**)parentCommits;
+
+  commit = GCCreateCommitFromTreeWithOptionalSignature(repository, tree, parents, parentCount, git_commit_author(amendedCommit), message, error);
+
+cleanup:
+  if (parentCommits) {
+    for (unsigned int i = 0; i < parentCount; ++i) {
+      git_commit_free(parentCommits[i]);
+    }
+    free(parentCommits);
+  }
+  git_tree_free(tree);
+  return commit;
+}

GitUpKit/Core/GCPrivate.h

@@ -119,6 +119,7 @@ extern BOOL GCGitOIDFromSHA1(NSString* sha1, git_oid* oid, NSError** error);
 extern BOOL GCGitOIDFromSHA1Prefix(NSString* prefix, git_oid* oid, NSError** error);
 extern NSData* GCCleanedUpCommitMessage(NSString* message);
 extern GCCommit* GCCreateCommitFromTreeWithOptionalSignature(GCRepository* repository, git_tree* tree, const git_commit** parents, NSUInteger count, const git_signature* author, NSString* message, NSError** error);
+extern GCCommit* GCCreateCommitFromCommitWithIndexAndOptionalSignature(GCRepository* repository, git_commit* commit, git_index* index, NSString* message, NSError** error);
 extern NSString* GCUserFromSignature(const git_signature* signature);
 extern const void* GCOIDCopyCallBack(CFAllocatorRef allocator, const void* value);
 extern Boolean GCOIDEqualCallBack(const void* value1, const void* value2);

GitUpKit/Core/GCRepository+HEAD.m

@@ -130,7 +130,6 @@ - (GCCommit*)createCommitFromHEADAndOtherParent:(GCCommit*)parent withMessage:(N
     goto cleanup;
   }
 
-  // The signing helper creates a commit object from an explicit libgit2 parent list; this array covers both normal and merge commits.
   parents[0] = headCommit;
   parents[1] = parent.private;
   commit = _CreateCommitFromIndex(self, index, parents, (headCommit ? (parent ? 2 : 1) : 0), NULL, message, error);
@@ -168,9 +167,6 @@ - (GCCommit*)createCommitByAmendingHEADWithMessage:(NSString*)message error:(NSE
   git_reference* headReference = NULL;
   git_commit* headCommit = NULL;
   git_index* index = NULL;
-  git_tree* tree = NULL;
-  git_commit** parentCommits = NULL;
-  unsigned int parentCount = 0;
   NSString* reflogMessage;
 
   CALL_LIBGIT2_FUNCTION_GOTO(cleanup, git_repository_head, &headReference, self.private);  // Returns a direct reference or GIT_EUNBORNBRANCH
@@ -182,22 +178,7 @@ - (GCCommit*)createCommitByAmendingHEADWithMessage:(NSString*)message error:(NSE
     goto cleanup;
   }
 
-  git_oid oid;
-  CALL_LIBGIT2_FUNCTION_GOTO(cleanup, git_index_write_tree_to, &oid, index, self.private);
-  CALL_LIBGIT2_FUNCTION_GOTO(cleanup, git_tree_lookup, &tree, self.private, &oid);
-  parentCount = git_commit_parentcount(headCommit);
-  if (parentCount) {
-    parentCommits = (git_commit**)calloc(parentCount, sizeof(git_commit*));
-    if (!parentCommits) {
-      GC_SET_GENERIC_ERROR(@"Unable to allocate commit parent list");
-      goto cleanup;
-    }
-    for (unsigned int i = 0; i < parentCount; ++i) {
-      CALL_LIBGIT2_FUNCTION_GOTO(cleanup, git_commit_parent, &parentCommits[i], headCommit, i);
-    }
-  }
-  // Amending preserves HEAD's original parents while creating a new commit object, so keep these parent commits alive through signing.
-  commit = GCCreateCommitFromTreeWithOptionalSignature(self, tree, (const git_commit**)parentCommits, parentCount, git_commit_author(headCommit), message, error);
+  commit = GCCreateCommitFromCommitWithIndexAndOptionalSignature(self, headCommit, index, message, error);
   if (commit == nil) {
     goto cleanup;
   }
@@ -213,13 +194,6 @@ - (GCCommit*)createCommitByAmendingHEADWithMessage:(NSString*)message error:(NSE
   success = YES;
 
 cleanup:
-  if (parentCommits) {
-    for (unsigned int i = 0, count = headCommit ? git_commit_parentcount(headCommit) : 0; i < count; ++i) {
-      git_commit_free(parentCommits[i]);
-    }
-    free(parentCommits);
-  }
-  git_tree_free(tree);
   git_index_free(index);
   git_commit_free(headCommit);
   git_reference_free(headReference);