From 8fde032ef17690a2354bd27e7c2f0288f677a541 Mon Sep 17 00:00:00 2001
From: oppiliappan <me@oppi.li>
Date: Wed, 15 Oct 2025 13:09:20 +0100
Subject: [PATCH] appview/pulls: fix regression in resubmitting fork based PRs

if the upstream was updated, fork based PRs would be unable to resubmit.
this is because the hidden tracking ref was not updated before
performing a comparison, it was performed *after*. the ordering of
events was incorrect.

additionaly, the RepoCompare call was being made against
pull.TargetBranch when it should have been against the hidden ref.

Signed-off-by: oppiliappan <me@oppi.li>
---
 appview/pulls/pulls.go | 53 +++++++++++++++++++++---------------------
 1 file changed, 27 insertions(+), 26 deletions(-)

diff --git a/appview/pulls/pulls.go b/appview/pulls/pulls.go
index dde7cb99..926cf35c 100644
--- a/appview/pulls/pulls.go
+++ b/appview/pulls/pulls.go
@@ -1695,32 +1695,6 @@ func (s *Pulls) resubmitFork(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// extract patch by performing compare
-	forkScheme := "http"
-	if !s.config.Core.Dev {
-		forkScheme = "https"
-	}
-	forkHost := fmt.Sprintf("%s://%s", forkScheme, forkRepo.Knot)
-	forkRepoId := fmt.Sprintf("%s/%s", forkRepo.Did, forkRepo.Name)
-	forkXrpcBytes, err := tangled.RepoCompare(r.Context(), &indigoxrpc.Client{Host: forkHost}, forkRepoId, pull.TargetBranch, pull.PullSource.Branch)
-	if err != nil {
-		if xrpcerr := xrpcclient.HandleXrpcErr(err); xrpcerr != nil {
-			log.Println("failed to call XRPC repo.compare for fork", xrpcerr)
-			s.pages.Notice(w, "resubmit-error", "Failed to create pull request. Try again later.")
-			return
-		}
-		log.Printf("failed to compare branches: %s", err)
-		s.pages.Notice(w, "resubmit-error", "Failed to create pull request. Try again later.")
-		return
-	}
-
-	var forkComparison types.RepoFormatPatchResponse
-	if err := json.Unmarshal(forkXrpcBytes, &forkComparison); err != nil {
-		log.Println("failed to decode XRPC compare response for fork", err)
-		s.pages.Notice(w, "resubmit-error", "Failed to create pull request. Try again later.")
-		return
-	}
-
 	// update the hidden tracking branch to latest
 	client, err := s.oauth.ServiceClient(
 		r,
@@ -1752,6 +1726,33 @@ func (s *Pulls) resubmitFork(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	hiddenRef := fmt.Sprintf("hidden/%s/%s", pull.PullSource.Branch, pull.TargetBranch)
+	// extract patch by performing compare
+	forkScheme := "http"
+	if !s.config.Core.Dev {
+		forkScheme = "https"
+	}
+	forkHost := fmt.Sprintf("%s://%s", forkScheme, forkRepo.Knot)
+	forkRepoId := fmt.Sprintf("%s/%s", forkRepo.Did, forkRepo.Name)
+	forkXrpcBytes, err := tangled.RepoCompare(r.Context(), &indigoxrpc.Client{Host: forkHost}, forkRepoId, hiddenRef, pull.PullSource.Branch)
+	if err != nil {
+		if xrpcerr := xrpcclient.HandleXrpcErr(err); xrpcerr != nil {
+			log.Println("failed to call XRPC repo.compare for fork", xrpcerr)
+			s.pages.Notice(w, "resubmit-error", "Failed to create pull request. Try again later.")
+			return
+		}
+		log.Printf("failed to compare branches: %s", err)
+		s.pages.Notice(w, "resubmit-error", "Failed to create pull request. Try again later.")
+		return
+	}
+
+	var forkComparison types.RepoFormatPatchResponse
+	if err := json.Unmarshal(forkXrpcBytes, &forkComparison); err != nil {
+		log.Println("failed to decode XRPC compare response for fork", err)
+		s.pages.Notice(w, "resubmit-error", "Failed to create pull request. Try again later.")
+		return
+	}
+
 	// Use the fork comparison we already made
 	comparison := forkComparison
 
-- 
2.51.2