plandex-ai/plandex · error

Error marshalling branches:

Error message

Error marshalling branches: 

What it means

ListBranchesHandler calls json.Marshal on the []*db.Branch slice and returns HTTP 500 'Error marshalling branches: <err>' if serialization fails. json.Marshal only errors on unsupported types (e.g. unexported fields with custom MarshalJSON returning an error, channels, funcs, or invalid UTF-8/cyclic data). In practice this is nearly always a bug in the Branch type's serialization, not in the request.

Source

Thrown at app/server/handlers/branches.go:71

			return err
		}

		branches = res

		return nil
	})

	if err != nil {
		log.Printf("Error getting branches: %v\n", err)
		http.Error(w, "Error getting branches: "+err.Error(), http.StatusInternalServerError)
		return
	}

	jsonBytes, err := json.Marshal(branches)

	if err != nil {
		log.Printf("Error marshalling branches: %v\n", err)
		http.Error(w, "Error marshalling branches: "+err.Error(), http.StatusInternalServerError)
		return
	}

	log.Println("Successfully retrieved branches")

	w.Write(jsonBytes)
}

func CreateBranchHandler(w http.ResponseWriter, r *http.Request) {
	log.Println("Received request for CreateBranchHandler")

	auth := Authenticate(w, r, true)
	if auth == nil {
		return
	}

	vars := mux.Vars(r)
	planId := vars["planId"]

View on GitHub (pinned to e2d772072e)

Solutions

1. Read the wrapped marshal error in the server log to identify the offending field
2. Inspect db.Branch for recently added fields with custom MarshalJSON or unsupported types
3. Fix the MarshalJSON implementation or mark the field with `json:"-"` to skip it

Example fix

// before
type Branch struct {
    Meta chan string `json:"meta"` // unsupported type
}
// after
type Branch struct {
    Meta chan string `json:"-"` // excluded from JSON
}

// server-side: this is a serialization bug; log full error and fail fast in tests
testBranches := []*db.Branch{{...}}
if _, err := json.Marshal(testBranches); err != nil {
    t.Fatalf("Branch type not JSON-serializable: %v", err)
}

When it happens

Trigger: The branches slice retrieved from ListPlanBranches contains a field whose MarshalJSON fails or an unsupported type (channel/func/cyclic reference) added to db.Branch; extremely rare in normal operation.

Common situations: A developer recently added a field to db.Branch (e.g. a custom struct or time-like type) with a broken MarshalJSON implementation; embedding a non-serializable type after a schema change.

Understand the failure class

Background: json.Marshal / "failed to marshal" errors in Go: why "unsupported type" happens and how to fix it — this error's family across 22 libraries.

Related errors

• Error marshalling response:
• Error marshalling invites:
• Error marshalling response
• Error marshalling contexts:
• Error marshalling response:

AI-assisted analysis of plandex-ai/plandex@e2d772072e (2026-09-05). Data as JSON: /api/errors/8ace9090b98ae025. Report an issue: GitHub.