withastro/astro · error · AstroError

PluginContentImportsError

PluginContentImportsError

Error message

Unexpected error processing content collection data.

What it means

A catch-all in vite-plugin-content-imports: while stringifying collection data for a generated module, something threw a value that is not an Error instance (for example a string thrown from a custom loader or a getter). Because there is no stack to preserve, Astro wraps it in PluginContentImportsError.

Solutions

Run astro build with verbose logging to identify the entry being processed when it throws.
Audit custom loader/transform code for throw statements raising strings or plain objects; always throw new Error(...).
Apply the serialization fixes for UnsupportedConfigTransformError — this error shares the same root cause.
If no custom code is involved, report an Astro issue with the data shape that triggered it.

Example fix

// before (in a custom loader)
if (!row.id) throw 'row missing id';

// after
if (!row.id) throw new Error(`row missing id in ${row}`);

Defensive patterns

Strategy: try-catch

Validate before calling

// Enforce Error-typed throws in your loader code
function assertValid(value, msg) {
  if (!value) throw new Error(msg); // never throw a bare string
}

Try / catch

try {
  await build();
} catch (e) {
  if (e instanceof Error && e.name === 'PluginContentImportsError') {
    // re-run with verbose logging to find the entry, then audit custom loader throws
  }
  throw e;
}

Prevention

Always throw new Error(...) with a message; never throw strings or plain objects.
Keep transform output serializable (see UnsupportedConfigTransformError).
Isolate third-party loaders when this appears to identify which one threw.

When it happens

Trigger: Custom loaders or transforms that throw non-Error values (throw 'bad data'); exotic objects whose getters throw plain strings during serialization.

Common situations: Almost always co-occurs with UnsupportedConfigTransformError; third-party loader bugs; defensive throw statements in shared code that raise strings.

Related errors

AI-assisted analysis of withastro/astro@e294953aa8 (2026-08-18). Data as JSON: /api/errors/cd45f556ea772dd3. Report an issue: GitHub.

Appendix: source

Thrown at packages/astro/src/content/vite-plugin-content-imports.ts:441

				return `new URL(${JSON.stringify(value.href)})`;
			}

			// For Astro assets, add a proxy to track references
			if (typeof value === 'object' && 'ASTRO_ASSET' in value) {
				const { ASTRO_ASSET, ...asset } = value;
				asset.fsPath = ASTRO_ASSET;
				return getProxyCode(asset, isSSR);
			}
		});
	} catch (e) {
		if (e instanceof Error) {
			throw new AstroError({
				...AstroErrorData.UnsupportedConfigTransformError,
				message: AstroErrorData.UnsupportedConfigTransformError.message(e.message),
				stack: e.stack,
			});
		} else {
			throw new AstroError({
				name: 'PluginContentImportsError',
				message: 'Unexpected error processing content collection data.',
			});
		}
	}
}

View on GitHub (pinned to e294953aa8)