oxc-project/oxc · error · OxcDiagnostic

Expected to return a value in render function.

Error message

Expected to return a value in render function.

What it means

Emitted by run of the vue require-render-return rule when a component's render function has at least one code path that does not return a value (checked via definitely_returns_in_all_codepaths). It is a control-flow guard: render must always return a VNode or rendering silently fails.

Source

Thrown at crates/oxc_linter/src/rules/vue/require_render_return.rs:14

use oxc_ast::AstKind;
use oxc_diagnostics::OxcDiagnostic;
use oxc_macros::declare_oxc_lint;
use oxc_span::{GetSpan, Span};

use crate::{
    AstNode,
    context::LintContext,
    rule::Rule,
    utils::{definitely_returns_in_all_codepaths, is_vue_component_options_object},
};

fn require_render_return_diagnostic(span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn("Expected to return a value in render function.")
        .with_help("All code paths inside a render function must return a value.")
        .with_label(span)
}

#[derive(Debug, Default, Clone)]
pub struct RequireRenderReturn;

declare_oxc_lint!(
    /// ### What it does
    ///
    /// Enforce that a `render` function always returns a value.
    ///
    /// ### Why is this bad?
    ///
    /// A Vue component's `render` function must produce a VNode tree. If a
    /// code path falls through without returning, Vue receives `undefined`
    /// and silently renders nothing.
    ///

View on GitHub (pinned to e1e7af627c)

Solutions

1. Ensure every branch of the render function returns a VNode, including else branches and early returns
2. Add a final fallback return statement, e.g. return h('div')

When it happens

Trigger: Thrown at crates/oxc_linter/src/rules/vue/require_render_return.rs:14 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of oxc-project/oxc@e1e7af627c (2026-08-20). Data as JSON: /api/errors/f1669e6c14658c82. Report an issue: GitHub.