Extract State Machine

State Machine Extractor

Overview

Identifies implicit and explicit state machines in code — status fields, enum-based states, transition methods, guard conditions, and actions. Produces structured state diagram data for visualization.

Detection Patterns

Enum-Based States

# Status/State enums
Grep: "enum.*(Status|State)" --glob "**/*.php"

# Backed enum cases
Grep: "case [A-Z]" --glob "**/*.php" -A 0
# Read full enum to get all cases

# Enum with methods (transition logic)
Grep: "function (canTransitionTo|allowedTransitions|next)" --glob "**/*.php"

Status Fields

# Status properties
Grep: "private.*\\$status|readonly.*Status|private.*Status \\$" --glob "**/*.php"

# Status setters/changers
Grep: "function (setStatus|changeStatus|updateStatus|transitionTo)" --glob "**/*.php"

# Status constants (legacy pattern)
Grep: "const STATUS_|const STATE_" --glob "**/*.php"

Transition Methods

# Named transition methods (domain verbs)
Grep: "function (activate|deactivate|approve|reject|cancel|complete|suspend|resume|archive|publish|draft|submit|confirm|expire|close|open|block|unblock|verify|process|ship|deliver|refund|pay)" --glob "**/Domain/**/*.php"

# Status check before transition (guard)
Grep: "if.*status.*!==|if.*status.*===|match.*status" --glob "**/*.php"

# Transition with event recording
Grep: "->(recordEvent|raise|apply).*new.*Event" --glob "**/*.php"

Switch/Match State Logic

# Match expression on status
Grep: "match.*\\(.*status|match.*\\(.*state|match.*\\(.*->getStatus" --glob "**/*.php"

# Switch on status
Grep: "switch.*\\(.*status|switch.*\\(.*state" --glob "**/*.php"

# State-dependent behavior
Grep: "case.*Status::|case.*State::" --glob "**/*.php"

Symfony Workflow Component

# Workflow configuration
Glob: "config/packages/workflow.yaml"
Glob: "config/packages/workflow.php"

# Workflow service usage
Grep: "WorkflowInterface|Workflow::" --glob "**/*.php"
Grep: "->can\\(|->apply\\(|->getMarking" --glob "**/*.php"

Analysis Process

Step 1: Find State Holders

For each entity/aggregate with a status field:

1. Read the enum/status definition — get all possible states
2. Find transition methods — methods that change the status
3. Extract guards — conditions checked before transition
4. Extract actions — what happens during/after transition
5. Find events — events raised on transition

Step 2: Build Transition Table

For each transition method found:

Read the method body:
1. What is the source state? (guard/precondition)
2. What is the target state? (assignment/return)
3. What conditions must be met? (if/match checks)
4. What side effects occur? (events, notifications)

Step 3: Validate Completeness

• Can every state be reached from the initial state?
• Are there dead-end states (no outgoing transitions)?
• Are there unreachable states?
• Are all transitions guarded?

Output Format

## State Machines

### Summary

| Entity | States | Transitions | Has Guards | Events |
|--------|--------|-------------|-----------|--------|
| Order | 6 | 8 | Yes | 5 |
| Payment | 4 | 5 | Yes | 3 |
| User | 3 | 4 | Partial | 2 |

### Order State Machine

#### States

| State | Description | Terminal |
|-------|-------------|---------|
| `draft` | Order created but not submitted | No |
| `pending` | Submitted, awaiting payment | No |
| `confirmed` | Payment received | No |
| `shipped` | Items dispatched | No |
| `delivered` | Items received by customer | Yes |
| `cancelled` | Order cancelled | Yes |

#### Transitions

| # | From | To | Method | Guard | Action |
|---|------|----|--------|-------|--------|
| 1 | draft | pending | submit() | Has items | Validate totals |
| 2 | pending | confirmed | confirm() | Payment OK | Record payment |
| 3 | confirmed | shipped | ship() | Items packed | Send tracking |
| 4 | shipped | delivered | deliver() | Tracking confirms | Close order |
| 5 | draft | cancelled | cancel() | - | Release items |
| 6 | pending | cancelled | cancel() | - | Refund if paid |
| 7 | confirmed | cancelled | cancel() | Not shipped | Refund payment |

#### State Diagram Data (Mermaid-ready)

stateDiagram-v2 [] --> draft draft --> pending : submit() draft --> cancelled : cancel() pending --> confirmed : confirm() pending --> cancelled : cancel() confirmed --> shipped : ship() confirmed --> cancelled : cancel() shipped --> delivered : deliver() delivered --> [] cancelled --> [*]

#### Guards Detail

| Transition | Guard Condition | Error on Failure |
|-----------|-----------------|-----------------|
| submit() | Order has at least 1 item | "Cannot submit empty order" |
| confirm() | Payment amount matches total | "Payment mismatch" |
| ship() | All items available in warehouse | "Items not available" |
| cancel() | Status is not shipped/delivered | "Cannot cancel shipped order" |

#### Events Raised

| Transition | Event | Listeners |
|-----------|-------|-----------|
| submit() | OrderSubmitted | InventoryReserve, NotifyAdmin |
| confirm() | OrderConfirmed | SendConfirmation, StartPacking |
| ship() | OrderShipped | SendTracking, NotifyCustomer |
| deliver() | OrderDelivered | RequestReview, CloseTicket |
| cancel() | OrderCancelled | ReleaseInventory, RefundPayment |

State Machine Quality Indicators

Common Anti-Patterns

Integration

This skill is used by:

• business-logic-analyst — documents state machines in domain
• diagram-designer — generates state diagrams from extracted data
• explain-business-process — references state transitions in workflows