linera-io/linera-protocol · error

Invalid protocol flag

Error message

Invalid protocol flag

What it means

When assembling a ResourceControlPolicy, the CLI parses each --flags string into the ProtocolFlag enum (strum EnumString) and collects the results into a BTreeSet. The expect panics when any flag string does not match a ProtocolFlag variant. In the current linera-execution the enum only defines the hidden variant _Reserved, so effectively every user-supplied flag value fails.

Source

Thrown at linera-service/src/cli/main.rs:729

                                            .map(|ids| {
                                                ids.into_iter().map(|s| s.parse()).collect::<Result<
                                                    BTreeSet<_>,
                                                    _,
                                                >>(
                                                )
                                            })
                                            .transpose()
                                            .expect("Invalid application ID")
                                            .unwrap_or(existing_policy.free_application_ids),
                                        flags: flags
                                            .map(|values| {
                                                values
                                                    .into_iter()
                                                    .map(|s| s.parse())
                                                    .collect::<Result<BTreeSet<_>, _>>()
                                            })
                                            .transpose()
                                            .expect("Invalid protocol flag")
                                            .unwrap_or(existing_policy.flags),
                                    };
                                    info!("{policy}");
                                    if committee.policy() == &policy {
                                        return Ok(ClientOutcome::Committed(None));
                                    }
                                }
                                _ => unreachable!(),
                            }
                            let new_committee = Committee::new(validators, policy)?;
                            chain_client
                                .stage_new_committee(new_committee)
                                .await
                                .map(|outcome| outcome.map(Some))
                        }
                    })
                    .await
                    .context("Failed to stage committee")?;

View on GitHub (pinned to 6c226ddcb3)

Solutions

1. Omit --flags entirely — the field is reserved for future protocol flags and has no user-facing values today
2. If a value must be supplied for testing, only the exact variant name '_Reserved' parses on current versions
3. Check the ProtocolFlag variants for your linera-execution version (linera-execution/src/policy.rs) before scripting flags
4. Remove the flag from templates/CI scripts that were written against a different toolchain

Example fix

# before
linera ... --flags experimental

# after
linera ...   # omit --flags; no protocol flags are accepted yet

# Only accept flag values known to the installed version (currently none / _Reserved).
if [ -n "$FLAGS" ] && [ "$FLAGS" != '_Reserved' ]; then echo "unsupported --flags value" >&2; exit 1; fi

When it happens

Trigger: Passing --flags with any value (e.g. 'foo', 'fast', '0') on a command that builds a policy: none of them map to a defined ProtocolFlag variant, so .parse() returns Err and the expect aborts.

Common situations: Assuming --flags accepts arbitrary feature toggles or future protocol names; carrying over flag values from other blockchains' CLIs; scripting genesis/config generation with a placeholder flag.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

• Invalid application ID
• expected whitespace after 'query' keyword
• expected an operation name after 'query', e.g. 'query MyQuer
• The input has not matched: {input}
• empty

AI-assisted analysis of linera-io/linera-protocol@6c226ddcb3 (2026-08-22). Data as JSON: /api/errors/547848aff38ea690. Report an issue: GitHub.