Add setting to disable the git apply step in test patch

custom/conf/app.example.ini

@@ -1036,6 +1036,9 @@ ROUTER = console
 ;;
 ;; Add co-authored-by and co-committed-by trailers if committer does not match author
 ;ADD_CO_COMMITTER_TRAILERS = true
+;;
+;; In addition to testing patches using the three-way merge method, re-test conflicting patches with git apply
+;TEST_CONFLICTING_PATCHES_WITH_GIT_APPLY = false
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

docs/content/doc/advanced/config-cheat-sheet.en-us.md

@@ -134,6 +134,7 @@ In addition there is _`StaticRootPath`_ which can be set as a built-in at build
 - `DEFAULT_MERGE_MESSAGE_OFFICIAL_APPROVERS_ONLY`: **true**: In default merge messages only include approvers who are officially allowed to review.
 - `POPULATE_SQUASH_COMMENT_WITH_COMMIT_MESSAGES`: **false**: In default squash-merge messages include the commit message of all commits comprising the pull request.
 - `ADD_CO_COMMITTER_TRAILERS`: **true**: Add co-authored-by and co-committed-by trailers to merge commit messages if committer does not match author.
+- `TEST_CONFLICTING_PATCHES_WITH_GIT_APPLY`: **false**: PR patches are tested using a three-way merge method to discover if there are conflicts. If this setting is set to **true**, conflicting patches will be retested using `git apply` - This was the previous behaviour in 1.18 (and earlier) but is somewhat inefficient. Please report if you find that this setting is required.
 
 ### Repository - Issue (`repository.issue`)
 

modules/setting/repository.go

@@ -82,6 +82,7 @@ var (
  DefaultMergeMessageOfficialApproversOnly bool
  PopulateSquashCommentWithCommitMessages bool
  AddCoCommitterTrailers bool
+ TestConflictingPatchesWithGitApply bool
  } `ini:"repository.pull-request"`
 
  // Issue Setting
@@ -204,6 +205,7 @@ var (
  DefaultMergeMessageOfficialApproversOnly bool
  PopulateSquashCommentWithCommitMessages bool
  AddCoCommitterTrailers bool
+ TestConflictingPatchesWithGitApply bool
  }{
  WorkInProgressPrefixes: []string{"WIP:", "[WIP]"},
  // Same as GitHub. See

services/pull/patch.go

@@ -23,6 +23,7 @@ import (
  "code.gitea.io/gitea/modules/log"
  "code.gitea.io/gitea/modules/process"
  repo_module "code.gitea.io/gitea/modules/repository"
+ "code.gitea.io/gitea/modules/setting"
  "code.gitea.io/gitea/modules/util"
 
  "github.com/gobwas/glob"
@@ -287,13 +288,15 @@ func checkConflicts(ctx context.Context, pr *issues_model.PullRequest, gitRepo *
 
  // 2. AttemptThreeWayMerge first - this is much quicker than plain patch to base
  description := fmt.Sprintf("PR[%d] %s/%s#%d", pr.ID, pr.BaseRepo.OwnerName, pr.BaseRepo.Name, pr.Index)
- conflict, _, err := AttemptThreeWayMerge(ctx,
+ conflict, conflictFiles, err := AttemptThreeWayMerge(ctx,
  tmpBasePath, gitRepo, pr.MergeBase, "base", "tracking", description)
  if err != nil {
  return false, err
  }
 
  if !conflict {
+ // No conflicts detected so we need to check if the patch is empty...
+ // a. Write the newly merged tree and check the new tree-hash
  var treeHash string
  treeHash, _, err = git.NewCommand(ctx, "write-tree").RunStdString(&git.RunOpts{Dir: tmpBasePath})
  if err != nil {
@@ -305,6 +308,8 @@ func checkConflicts(ctx context.Context, pr *issues_model.PullRequest, gitRepo *
  if err != nil {
  return false, err
  }
+
+ // b. compare the new tree-hash with the base tree hash
  if treeHash == baseTree.ID.String() {
  log.Debug("PullRequest[%d]: Patch is empty - ignoring", pr.ID)
  pr.Status = issues_model.PullRequestStatusEmpty
@@ -313,9 +318,17 @@ func checkConflicts(ctx context.Context, pr *issues_model.PullRequest, gitRepo *
  return false, nil
  }
 
- // 3. OK read-tree has failed so we need to try a different thing - this might actually succeed where the above fails due to whitespace handling.
+ // 3. OK the three-way merge method has detected conflicts
+ // 3a. Are still testing with GitApply? If not set the conflict status and move on
+ if !setting.Repository.PullRequest.TestConflictingPatchesWithGitApply {
+ pr.Status = issues_model.PullRequestStatusConflict
+ pr.ConflictedFiles = conflictFiles
+
+ log.Trace("Found %d files conflicted: %v", len(pr.ConflictedFiles), pr.ConflictedFiles)
+ return true, nil
+ }
 
- // 3a. Create a plain patch from head to base
+ // 3b. Create a plain patch from head to base
  tmpPatchFile, err := os.CreateTemp("", "patch")
  if err != nil {
  log.Error("Unable to create temporary patch file! Error: %v", err)
@@ -338,7 +351,7 @@ func checkConflicts(ctx context.Context, pr *issues_model.PullRequest, gitRepo *
  patchPath := tmpPatchFile.Name()
  tmpPatchFile.Close()
 
- // 3b. if the size of that patch is 0 - there can be no conflicts!
+ // 3c. if the size of that patch is 0 - there can be no conflicts!
  if stat.Size() == 0 {
  log.Debug("PullRequest[%d]: Patch is empty - ignoring", pr.ID)
  pr.Status = issues_model.PullRequestStatusEmpty