Detect conflicts with 3way merge (#18536) (#18537)

Backport #18536

Unforunately git apply --3way reports conflicts differently than standard patches
resulting in conflicts being missed.

Adjust the conflict detection code to account for this different error reporting.

Fix #18514

Signed-off-by: Andrew Thornton <art27@cantab.net>

diff --git a/services/pull/patch.go b/services/pull/patch.go
index 0eba3f86ed5af0be241c8396f3b741ff2172a0f9..ee10c97392f2428dc0e50dac5ac39b7886c6bd41 100644 (file)
--- a/services/pull/patch.go
+++ b/services/pull/patch.go
@@ -339,8 +339,10 @@ func checkConflicts(pr *models.PullRequest, gitRepo *git.Repository, tmpBasePath
        if prConfig.IgnoreWhitespaceConflicts {
                args = append(args, "--ignore-whitespace")
        }
+       is3way := false
        if git.CheckGitVersionAtLeast("2.32.0") == nil {
                args = append(args, "--3way")
+               is3way = true
        }
        args = append(args, patchPath)
        pr.ConflictedFiles = make([]string, 0, 5)
@@ -379,6 +381,9 @@ func checkConflicts(pr *models.PullRequest, gitRepo *git.Repository, tmpBasePath
 
                                const prefix = "error: patch failed:"
                                const errorPrefix = "error: "
+                               const threewayFailed = "Failed to perform three-way merge..."
+                               const appliedPatchPrefix = "Applied patch to '"
+                               const withConflicts = "' with conflicts."
 
                                conflictMap := map[string]bool{}
 
@@ -390,6 +395,8 @@ func checkConflicts(pr *models.PullRequest, gitRepo *git.Repository, tmpBasePath
                                                conflict = true
                                                filepath := strings.TrimSpace(strings.Split(line[len(prefix):], ":")[0])
                                                conflictMap[filepath] = true
+                                       } else if is3way && line == threewayFailed {
+                                               conflict = true
                                        } else if strings.HasPrefix(line, errorPrefix) {
                                                conflict = true
                                                for _, suffix := range patchErrorSuffices {
@@ -401,6 +408,12 @@ func checkConflicts(pr *models.PullRequest, gitRepo *git.Repository, tmpBasePath
                                                                break
                                                        }
                                                }
+                                       } else if is3way && strings.HasPrefix(line, appliedPatchPrefix) && strings.HasSuffix(line, withConflicts) {
+                                               conflict = true
+                                               filepath := strings.TrimPrefix(strings.TrimSuffix(line, withConflicts), appliedPatchPrefix)
+                                               if filepath != "" {
+                                                       conflictMap[filepath] = true
+                                               }
                                        }
                                        // only list 10 conflicted files
                                        if len(conflictMap) >= 10 {