Workflow If/Else: if only one of the branches has intermediate step, the next steps are skipped and run stops

[ClaireGz]

Summary

When an If/Else has a step that is shared by both branches (a merge / convergence node) — i.e. the merge node is the direct target of one branch and is reached downstream of the other branch — that merge node (and everything after it) is silently SKIPPED when the other branch is taken. The run then reports COMPLETED, so it looks successful while having done nothing past the branch.

See test example here:

Minimal reproduction (3 nodes)

Structure:

If/Else
  ├ (branch A)  → Update Record #1 → Update Record #M
  └ (branch B / else) ───────────────→ Update Record #M      (#M is shared by both)

Trigger so that branch A is taken.

Actual (run steps):

• If/Else → SUCCESS
• Update Record #1 (on branch A) → SUCCESS
• Update Record #M (shared merge) → SKIPPED
• Run status → COMPLETED

So the branch that was taken ran its first step, then the shared node was skipped even though branch A flows into it.

Expected: Update Record #M runs (it is reachable from the taken branch). The run should reflect that the merge node executed.

Workaround

A workaround that can be used is this. We add an intermediate fake step for "else" so it's not skipped by the "if"

Expectd behaviour

We should be able to have if / else with only a step for the if but not for the else (and other way around)

[sonarly]

🟠 Sonarly Analysis — High Severity

Workflow convergence marks the taken branch's shared step SKIPPED

When both If/Else branches converge on the same step, the executor marks that step as SKIPPED because it is the direct target of the non-selected branch. The workflow then completes successfully even though the selected branch and all downstream work were not executed.

Root Cause

Proximate cause: getNextStepIdsToExecute treats every first node of a non-selected If/Else branch as unconditionally skippable. For a selected branch A and non-selected branch B, it returns:

nextStepIdsToExecute: matchingBranch?.nextStepIds,
nextStepIdsToSkip: nonMatchingBranches.flatMap(
  (branch) => branch.nextStepIds,
),

[ref:packages/twenty-server/src/modules/workflow/workflow-executor/workspace-services/workflow-executor.workspace-service.ts:275-296]

The executor awaits skipAndFailSafelyStepsThenContinue before executing the selected branch:

if (isDefined(nextStepIdsToSkip)) {
  await this.skipAndFailSafelyStepsThenContinue(...);
}

if (isDefined(nextStepIdsToExecute)) {
  await this.executeFromSteps(...);
}

[ref:packages/twenty-server/src/modules/workflow/workflow-executor/workspace-services/workflow-executor.workspace-service.ts:214-238]

skipAndFailSafelyStepsThenContinue writes every supplied skip ID with status SKIPPED [ref:packages/twenty-server/src/modules/workflow/workflow-executor/workspace-services/workflow-executor.workspace-service.ts:535-564]. Therefore, for this graph:

IfElse
  branch A -> Update1 -> Merge
  branch B -> Merge

when branch A is selected, Merge is also the direct target of branch B and is included in nextStepIdsToSkip. It is persisted as SKIPPED before Update1 runs.

When the selected path later reaches Merge, shouldExecuteStep immediately returns false because stepHasBeenStarted considers any status other than NOT_STARTED to be started [ref:packages/twenty-server/src/modules/workflow/workflow-executor/utils/should-execute-step.util.ts:34-41]. The shared node therefore cannot be reactivated by the successful selected branch.

A second structural defect compounds the problem: If/Else branch edges are stored in settings.input.branches[].nextStepIds [ref:packages/twenty-shared/src/workflow/types/StepIfElseBranch.ts:1-5], but normal parent detection only examines parentStep.nextStepIds [ref:packages/twenty-server/src/modules/workflow/workflow-executor/utils/should-execute-step.util.ts:38-46] [ref:packages/twenty-server/src/modules/workflow/workflow-executor/utils/should-skip-step-execution.util.ts:25-39]. Thus the executor does not consistently model the If/Else node as a parent of branch roots or convergence nodes.

The green run status is a consequence of the incorrect SKIPPED state, not a separate action failure. workflowShouldKeepRunning only searches ordinary nextStepIds for NOT_STARTED executable children [ref:packages/twenty-server/src/modules/workflow/workflow-executor/utils/workflow-should-keep-running.util.ts:20-47]. After the shared node is incorrectly marked skipped, no running or pending steps remain and no executable child is detected, so computeWorkflowRunStatus ends the run as COMPLETED [ref:packages/twenty-server/src/modules/workflow/workflow-executor/workspace-services/workflow-executor.workspace-service.ts:342-361].

Triggering cause: the affected workflow version contains a valid convergence graph in which the same node is both the non-selected branch's direct target and a downstream target of the selected branch. The reported one-hop selected path exposes the defect immediately. No evidence is available to attribute the incident to a traffic spike, external dependency, configuration change, or deployment timing.

Git history shows the direct regression in 748e614f6c1c425d091d64647913cf5b14c37d54 (Workflow bug fixes (#17886)), which added propagation of non-selected If/Else branch roots as nextStepIdsToSkip and modified the workflow executor [ref:git show --stat 748e614]. The repository's earlier If/Else implementation was introduced by dff5e3cd7b6c0f0f0ff33cad1a743c771940dcad [ref:git show --stat dff5e3c].

Blame commit: dff5e3cd by abdulrahmancodes — feat: Add If/Else node (#16833)

Suggested Fix

Updated If/Else execution to preserve converging nodes. The executor now computes nodes reachable from the selected branch and excludes shared convergence nodes from the non-selected skip set. A workflow-specific child-edge helper is used by step execution, skip detection, workflow continuation, and status computation so branch-specific settings.input.branches[].nextStepIds are treated as real graph edges. The delayed workflow job path now supplies the workflow steps when recalculating branch transitions.

Added regression coverage for a selected branch converging with a skipped branch, branch-root execution, and pending branch continuation.

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