influxdata/influxdb · error · syn::Error

duplicate `flags`

Error message

duplicate `flags`

What it means

Compile-time error from the influxdb3_catalog_macros attribute parser: the `flags = <int>` key appears more than once in the macro invocation's attribute list. During `parse`, each recognized key is written into a slot Option, and a repeat assignment triggers this syn::Error at the duplicate key's span. It is a syntax-validation guard over macro input, not a runtime catalog error; resolve by specifying `flags` at most once.

Solutions

1. Keep one `flags = ...` and merge the intended values into a single expression
2. Delete the redundant flags entry

Example fix

// before
#[catalog(id = record_ids::X, shape = 0x1, flags = A, flags = B)]
// after
#[catalog(id = record_ids::X, shape = 0x1, flags = A | B)]

// Exactly one flags argument per attribute; merge values instead:
// bad:  flags = A, flags = B
// good: flags = A | B

When it happens

Trigger: Writing `#[catalog(id = ..., flags = FOO, flags = BAR)]` in the same attribute.

Common situations: Combining flags from two examples without merging values; generated attributes appending defaults when flags already exist.

Understand the failure class

Background: Conflicting config options: "cannot be used together" — configuration validation errors across open-source libraries — this error's family across 162 libraries.

Related errors

• duplicate `id`
• duplicate `shape`
• expected an argument name
• expected `name = value`; supported arguments are `id`…
• missing `id = record_ids::SOME_CONST`

AI-assisted analysis of influxdata/influxdb@06200ef96b (2026-09-19). Data as JSON: /api/errors/324f96ef5e6e9165. Report an issue: GitHub.

Appendix: source

Thrown at influxdb3_catalog_macros/src/lib.rs:115

                "shape" => {
                    let span = nv.value.span();
                    let Expr::Lit(syn::ExprLit {
                        lit: syn::Lit::Int(lit),
                        ..
                    }) = nv.value
                    else {
                        return Err(syn::Error::new(
                            span,
                            "`shape` must be an integer literal, e.g. `shape = 0xbba17476`",
                        ));
                    };
                    if shape.replace(lit).is_some() {
                        return Err(syn::Error::new(nv.path.span(), "duplicate `shape`"));
                    }
                }
                "flags" => {
                    if flags.replace(nv.value).is_some() {
                        return Err(syn::Error::new(nv.path.span(), "duplicate `flags`"));
                    }
                }
                other => {
                    return Err(syn::Error::new(
                        nv.path.span(),
                        format!(
                            "unknown argument `{other}`; supported arguments are `id`, `shape`, `flags`"
                        ),
                    ));
                }
            }
        }

        let id = id.ok_or_else(|| {
            syn::Error::new(
                proc_macro2::Span::call_site(),
                "missing `id = record_ids::SOME_CONST`",
            )

View on GitHub (pinned to 06200ef96b)