fix(pr): prefer an open pull request over a merged one recorded by checkout

Signed-off-by: bircni <bircni@icloud.com>

internal/app/ref_test.go

@@ -6,6 +6,7 @@ package app
 import (
 	"context"
 	"net/http"
+	"strings"
 	"testing"
 
 	"gitea.dev/tea/internal/clierr"
@@ -59,10 +60,18 @@ func TestParseRefAcceptsNumbersQualifiedNumbersAndURLs(t *testing.T) {
 
 // refApplication returns an application authenticated against a server listing the open pull
 // requests #3 (feat/one in alice/project), #4 (feat/two), #17 (fix in bob/project) and two
-// pull requests from branch dup.
+// pull requests from branch dup. Viewing one pull request finds it open, except the merged #30.
 func refApplication(t *testing.T, gitResults map[string]string) (*application, string) {
 	t.Helper()
 	server := newAuthenticatedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if number, ok := strings.CutPrefix(r.URL.Path, "/api/v1/repos/alice/project/pulls/"); ok {
+			state := "open"
+			if number == "30" {
+				state = "closed"
+			}
+			_, _ = w.Write([]byte(`{"number":` + number + `,"state":"` + state + `","merged":true}`))
+			return
+		}
 		require.Equal(t, "/api/v1/repos/alice/project/pulls", r.URL.Path)
 		writeFirstPage(w, r, `[
 			{"number":3,"head":{"ref":"feat/one","repo":{"full_name":"alice/project"}}},
@@ -111,6 +120,8 @@ func TestPullSelectorDefaultsToTheCheckedOutBranch(t *testing.T) {
 	}{
 		{"recorded by pr checkout", branch("pr/17", map[string]string{"tea-pr": "17", "tea-base-remote": "origin", "remote": "pulls/bob/project", "merge": "refs/heads/fix"}), 17, ""},
 		{"head branch name kept by pr checkout", branch("fix", map[string]string{"tea-pr": "17", "tea-base-remote": "origin"}), 17, ""},
+		{"recorded but merged, the head branch has a newer one", branch("fix", map[string]string{"tea-pr": "30", "tea-base-remote": "origin"}), 17, ""},
+		{"recorded but merged, no open one", branch("gone", map[string]string{"tea-pr": "30", "tea-base-remote": "origin"}), 30, ""},
 		{"recorded for another repository", branch("pr/9", map[string]string{"tea-pr": "9", "tea-base-remote": "fork", "remote": "fork", "merge": "refs/heads/fix"}), 17, ""},
 		{"upstream branch and owner", branch("local", map[string]string{"remote": "origin", "merge": "refs/heads/feat/one"}), 3, ""},
 		{"upstream owner tells forks apart", branch("dup", map[string]string{"remote": "pulls/carol/project", "merge": "refs/heads/dup"}), 21, ""},