error while creating a new delegation period record: %w

Error message

error while creating a new delegation period record: %w

What it means

Companion to the BeforeDelegationCreated panic in uniond export: after each delegation is re-created, AfterDelegationModified is replayed to write the new delegation-period record. The comment again notes the stock hook always returns nil, so the panic guards only against a distribution keeper whose hook implementation returns an error during export.

Source

Thrown at uniond/app/export.go:158

		return false
	})

	// reinitialize all delegations
	for _, del := range dels {
		valAddr, err := sdk.ValAddressFromBech32(del.ValidatorAddress)
		if err != nil {
			panic(err)
		}
		delAddr := sdk.MustAccAddressFromBech32(del.DelegatorAddress)

		if err := app.DistrKeeper.Hooks().BeforeDelegationCreated(ctx, delAddr, valAddr); err != nil {
			// never called as BeforeDelegationCreated always returns nil
			panic(fmt.Errorf("error while incrementing period: %w", err))
		}

		if err := app.DistrKeeper.Hooks().AfterDelegationModified(ctx, delAddr, valAddr); err != nil {
			// never called as AfterDelegationModified always returns nil
			panic(fmt.Errorf("error while creating a new delegation period record: %w", err))
		}
	}

	// reset context height
	ctx = ctx.WithBlockHeight(height)

	/* Handle staking state. */

	// iterate through redelegations, reset creation height
	err = app.StakingKeeper.IterateRedelegations(ctx, func(_ int64, red stakingtypes.Redelegation) (stop bool) {
		for i := range red.Entries {
			red.Entries[i].CreationHeight = 0
		}
		err = app.StakingKeeper.SetRedelegation(ctx, red)
		if err != nil {
			panic(err)
		}
		return false

View on GitHub (pinned to 031785bb6d)

Solutions

Reproduce with the stock uniond binary — if it does not panic, the cause is your build's hook overrides
Audit everything wrapped around app.DistrKeeper.Hooks() for error returns
Pin/align the vendored cosmos-sdk version
In forks, keep these hooks returning nil during export or replace the panics with explicit error handling

Defensive patterns

Strategy: validation

Validate before calling

# Confirm the distr hooks your build will replay are the stock nil-returning ones
grep -rn "AfterDelegationModified" $(go env GOMODCACHE)/github.com/cosmos/cosmos-sdk@*/x/distribution/keeper/hooks.go | head

Prevention

Do not wrap DistrKeeper hooks with middleware that can error
Re-run export in CI after any SDK upgrade to catch changed hook contracts
Keep forks' export.go in sync with upstream simapp assumptions
Document any hook that can return an error so operators know export will panic

When it happens

Trigger: uniond export with a custom DistrKeeper/hooks wrapper whose AfterDelegationModified returns a non-nil error, or SDK behavior drift after a version bump. On an unmodified build with the vendored SDK this path does not execute.

Common situations: Forked hook middleware that validates delegations; SDK upgrades altering hook contracts; test setups injecting erroring hooks.

Related errors

AI-assisted analysis of unionlabs/union@031785bb6d (2026-08-16). Data as JSON: /api/errors/cd43a22d4fbdd4d5. Report an issue: GitHub.