Show conflicts to parent branch

github.go

@@ -26,16 +26,21 @@ type GitHubWriteService interface {
 }
 
 type GitHubClient struct {
-	endpoint string
-	token    string
-	http     *http.Client
+	endpoint      string
+	token         string
+	http          *http.Client
+	conflicts     conflictFileLoader
+	conflictMu    sync.Mutex
+	conflictCache map[string]conflictFileResult
 }
 
 func NewGitHubClient(endpoint, token string) *GitHubClient {
 	return &GitHubClient{
-		endpoint: endpoint,
-		token:    token,
-		http:     &http.Client{Timeout: 20 * time.Second},
+		endpoint:      endpoint,
+		token:         token,
+		http:          &http.Client{Timeout: 20 * time.Second},
+		conflicts:     analyzeConflictFiles,
+		conflictCache: make(map[string]conflictFileResult),
 	}
 }
 
@@ -272,6 +277,7 @@ func nullableCursor(cursor string) any {
 const detailsQuery = `
 query PullRequestDetails($owner: String!, $name: String!, $number: Int!) {
   repository(owner: $owner, name: $name) {
+    url
     viewerPermission
     defaultBranchRef { name }
     rulesets(first: 100, includeParents: true, targets: [BRANCH]) {
@@ -288,6 +294,7 @@ query PullRequestDetails($owner: String!, $name: String!, $number: Int!) {
       baseRefName headRefName headRefOid
       viewerCanUpdate viewerCanReact viewerCanSubscribe viewerCanEnableAutoMerge
       baseRef {
+        target { ... on Commit { oid } }
         branchProtectionRule {
           requiresApprovingReviews requiredApprovingReviewCount
           requiresStatusChecks requiresConversationResolution
@@ -586,6 +593,7 @@ type githubPullRequestDetails struct {
 	Author                                                                        *githubActor
 	ViewerCanUpdate, ViewerCanReact, ViewerCanSubscribe, ViewerCanEnableAutoMerge bool
 	BaseRef                                                                       *struct {
+		Target               *struct{ OID string }
 		BranchProtectionRule *struct {
 			RequiresApprovingReviews, RequiresStatusChecks           bool
 			RequiresConversationResolution, RequiresCodeOwnerReviews bool
@@ -885,6 +893,7 @@ func (c *GitHubClient) allCheckAnnotations(
 func (c *GitHubClient) GetPullRequest(ctx context.Context, owner, name string, number int) (PRDetails, error) {
 	var data struct {
 		Repository *struct {
+			URL              string
 			ViewerPermission string `json:"viewerPermission"`
 			DefaultBranchRef *struct{ Name string }
 			Rulesets         struct{ Nodes []githubRuleset }
@@ -909,6 +918,8 @@ func (c *GitHubClient) GetPullRequest(ctx context.Context, owner, name string, n
 		reviewErr         error
 		timelineErr       error
 		checkErr          error
+		conflictFiles     []string
+		conflictFileErr   error
 		wait              sync.WaitGroup
 	)
 	wait.Add(4)
@@ -936,6 +947,19 @@ func (c *GitHubClient) GetPullRequest(ctx context.Context, owner, name string, n
 			checkNodes, checkErr = c.allCheckContexts(ctx, rollup.Contexts, rollup.ID)
 		}()
 	}
+	if node.Mergeable == "CONFLICTING" && c.conflicts != nil {
+		wait.Add(1)
+		go func() {
+			defer wait.Done()
+			baseOID := ""
+			if node.BaseRef != nil && node.BaseRef.Target != nil {
+				baseOID = node.BaseRef.Target.OID
+			}
+			conflictFiles, conflictFileErr = c.loadConflictFiles(
+				ctx, data.Repository.URL, number, node.BaseRefName, baseOID, node.HeadRefOID,
+			)
+		}()
+	}
 	wait.Wait()
 	for _, err := range []error{threadErr, conversationErr, reviewErr, timelineErr, checkErr} {
 		if err != nil {
@@ -951,7 +975,8 @@ func (c *GitHubClient) GetPullRequest(ctx context.Context, owner, name string, n
 		},
 		Body: node.Body, CreatedAt: node.CreatedAt, BaseRef: node.BaseRefName, HeadRef: node.HeadRefName,
 		HeadOID: node.HeadRefOID, Mergeable: node.Mergeable, MergeState: node.MergeStateStatus,
-		Additions: node.Additions, Deletions: node.Deletions, ChangedFiles: node.ChangedFiles,
+		ConflictFiles: conflictFiles,
+		Additions:     node.Additions, Deletions: node.Deletions, ChangedFiles: node.ChangedFiles,
 		CommitCount: node.Commits.TotalCount, CommentCount: node.Comments.TotalCount,
 		CheckState: "NONE", ReviewDecision: node.ReviewDecision,
 		Permissions: ViewerPermissions{
@@ -960,6 +985,9 @@ func (c *GitHubClient) GetPullRequest(ctx context.Context, owner, name string, n
 			CanSubscribe: node.ViewerCanSubscribe, CanEnableMerge: node.ViewerCanEnableAutoMerge,
 		},
 	}
+	if conflictFileErr != nil {
+		details.ConflictFileError = conflictFileErr.Error()
+	}
 	if node.BaseRef != nil && node.BaseRef.BranchProtectionRule != nil {
 		rule := node.BaseRef.BranchProtectionRule
 		details.Requirements = MergeRequirements{