Feature: Plan edge case scenarios
  As a QA engineer
  I want to verify that plan operations handle edge cases correctly
  So that concurrent execution, resource conflicts, validation chains, and rollbacks are robust

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  # Section 1: Concurrent plan execution edge cases
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  Scenario: Concurrent strategize start attempts on same plan
    Given I have a plan lifecycle service
    And I have a plan in strategize phase with queued state
    When I start strategize on the plan
    And I try to start strategize on the same plan again
    Then the second strategize start should raise a plan not ready error

  Scenario: Concurrent execute start attempts on same plan
    Given I have a plan lifecycle service
    And I have a plan in execute phase with queued state
    When I start execute on the plan
    And I try to start execute on the same plan again
    Then the second execute start should raise a plan not ready error

  Scenario: Concurrent apply start attempts on same plan
    Given I have a plan lifecycle service
    And I have a plan in apply phase with queued state
    When I start apply on the plan
    And I try to start apply on the same plan again
    Then the second apply start should raise a plan not ready error

  Scenario: Concurrent complete and fail on same strategize phase
    Given I have a plan lifecycle service
    And I have a plan in strategize phase with processing state
    When I complete strategize on the plan
    And I try to fail strategize with error "Late failure"
    Then the plan should be in complete state
    And the plan error message should still be "Late failure"

  Scenario: Two plans created from same action simultaneously
    Given I have a plan lifecycle service
    And I have an available action "local/concurrent-action"
    When I use the action to create plan for project "proj-a"
    And I use the action to create plan for project "proj-b"
    Then two distinct plans should exist
    And each plan should have a unique plan id

  Scenario: Concurrent phase transitions on different plans
    Given I have a plan lifecycle service
    And I have two plans at different lifecycle stages
    When I transition plan A from strategize to execute
    And I transition plan B from execute to apply
    Then plan A should be in execute phase
    And plan B should be in apply phase

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  # Section 2: Resource conflict scenarios
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  Scenario: Apply changes when target file is read-only
    Given I have a temporary test directory for edge case plan service
    And I have a Unit of Work instance for edge case plan testing
    And I have an edge case PlanService instance
    And I have a saved project with current plan for edge cases
    And the plan has a pending MODIFY change for a read-only file
    When I try to apply the edge case changes
    Then a PlanError should be raised mentioning file apply failure

  Scenario: Apply changes with overlapping file paths in a single plan
    Given I have a temporary test directory for edge case plan service
    And I have a Unit of Work instance for edge case plan testing
    And I have an edge case PlanService instance
    And I have a saved project with current plan for edge cases
    And the plan has a CREATE change and a MODIFY change for the same file
    When I apply the edge case changes
    Then the file should contain the final modified content
    And 2 changes should be marked as applied

  Scenario: Apply CREATE change with None content
    Given I have a temporary test directory for edge case plan service
    And I have a Unit of Work instance for edge case plan testing
    And I have an edge case PlanService instance
    And I have a saved project with current plan for edge cases
    And the plan has a CREATE change with None content
    When I apply the edge case changes
    Then the created file should be empty
    And 1 changes should be marked as applied

  Scenario: Apply MOVE change with missing source file
    Given I have a temporary test directory for edge case plan service
    And I have a Unit of Work instance for edge case plan testing
    And I have an edge case PlanService instance
    And I have a saved project with current plan for edge cases
    And the plan has a MOVE change where source does not exist
    When I apply the edge case changes
    Then the destination file should not exist
    And 1 changes should be marked as applied

  Scenario: Apply DELETE change for already-deleted file
    Given I have a temporary test directory for edge case plan service
    And I have a Unit of Work instance for edge case plan testing
    And I have an edge case PlanService instance
    And I have a saved project with current plan for edge cases
    And the plan has a DELETE change for an already-deleted file
    When I apply the edge case changes
    Then 1 changes should be marked as applied

  Scenario: Apply changes with file path containing spaces
    Given I have a temporary test directory for edge case plan service
    And I have a Unit of Work instance for edge case plan testing
    And I have an edge case PlanService instance
    And I have a saved project with current plan for edge cases
    And the plan has a CREATE change with a file path containing spaces
    When I apply the edge case changes
    Then the file with spaces in path should exist with correct content

  Scenario: Apply changes with deeply nested directory creation
    Given I have a temporary test directory for edge case plan service
    And I have a Unit of Work instance for edge case plan testing
    And I have an edge case PlanService instance
    And I have a saved project with current plan for edge cases
    And the plan has a CREATE change in a deeply nested directory
    When I apply the edge case changes
    Then the deeply nested file should exist

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  # Section 2b: Path traversal rejection (H4)
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  Scenario: Apply CREATE change with relative path traversal is rejected
    Given I have a temporary test directory for edge case plan service
    And I have a Unit of Work instance for edge case plan testing
    And I have an edge case PlanService instance
    And I have a saved project with current plan for edge cases
    And the plan has a CREATE change with a path traversal in file_path
    When I try to apply the edge case changes
    Then a PlanError should be raised mentioning path traversal

  Scenario: Apply MODIFY change with absolute path outside project is rejected
    Given I have a temporary test directory for edge case plan service
    And I have a Unit of Work instance for edge case plan testing
    And I have an edge case PlanService instance
    And I have a saved project with current plan for edge cases
    And the plan has a MODIFY change with an absolute path outside the project
    When I try to apply the edge case changes
    Then a PlanError should be raised mentioning path traversal

  Scenario: Apply DELETE change with path traversal is rejected
    Given I have a temporary test directory for edge case plan service
    And I have a Unit of Work instance for edge case plan testing
    And I have an edge case PlanService instance
    And I have a saved project with current plan for edge cases
    And the plan has a DELETE change with a path traversal in file_path
    When I try to apply the edge case changes
    Then a PlanError should be raised mentioning path traversal

  Scenario: Apply MOVE change with path traversal in new_path is rejected
    Given I have a temporary test directory for edge case plan service
    And I have a Unit of Work instance for edge case plan testing
    And I have an edge case PlanService instance
    And I have a saved project with current plan for edge cases
    And the plan has a MOVE change with a path traversal in new_path
    When I try to apply the edge case changes
    Then a PlanError should be raised mentioning path traversal

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  # Section 3: Validation failure chains
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  Scenario: Action use with multiple simultaneous argument validation failures
    Given I have a plan lifecycle service
    And I have an available action with multiple typed arguments
    When I try to use the action with wrong types and missing required args
    Then a validation error should list multiple argument errors

  Scenario: Action use with unknown arguments alongside missing required
    Given I have a plan lifecycle service
    And I have an available action with one required argument "count" of type "int"
    When I try to use the action with unknown argument "bogus" and no required args
    Then a validation error should mention both missing and unknown arguments

  Scenario: Plan model rejects empty description
    When I try to create an edge case plan with empty description
    Then an Edge Case Pydantic validation error should be raised

  Scenario: Plan model rejects invalid phase value
    When I try to create an edge case plan with invalid phase value
    Then an Edge Case Pydantic validation error should be raised

  Scenario: NamespacedName rejects invalid characters in namespace
    When I try to parse a namespaced name with special characters "inv@lid/action"
    Then an Edge Case Pydantic validation error should be raised

  Scenario: NamespacedName rejects invalid characters in name
    When I try to parse a namespaced name with special chars in name "local/my action!"
    Then an Edge Case Pydantic validation error should be raised

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  # Section 4: Rollback edge cases
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  Scenario: Partial apply failure leaves earlier changes applied on disk
    Given I have a temporary test directory for edge case plan service
    And I have a Unit of Work instance for edge case plan testing
    And I have an edge case PlanService instance
    And I have a saved project with current plan for edge cases
    And the plan has a valid CREATE change followed by a failing MODIFY change
    When I try to apply the edge case changes
    Then a PlanError should be raised mentioning file apply failure
    And the first file should exist on disk despite the error
    And the second file should remain unchanged on disk

  Scenario: Fail strategize after start does not reset to queued
    Given I have a plan lifecycle service
    And I have a plan in strategize phase with processing state
    When strategize fails with error "Provider timeout"
    Then the lifecycle plan processing state should be "errored"
    And the plan cannot be restarted from errored state

  Scenario: Fail execute preserves the error message
    Given I have a plan lifecycle service
    And I have a plan in execute phase with processing state
    When execute fails with error "Code generation failed"
    Then the lifecycle plan processing state should be "errored"
    And the lifecycle plan error message should be "Code generation failed"

  Scenario: Fail apply after partial processing
    Given I have a plan lifecycle service
    And I have a plan in apply phase with processing state
    When apply fails with error "Disk full during write"
    Then the lifecycle plan processing state should be "errored"
    And the lifecycle plan error message should be "Disk full during write"
    And the plan should be terminal

  Scenario: Cancel plan clears processing but does not revert to previous phase
    Given I have a plan lifecycle service
    And I have a plan in execute phase with processing state
    When I cancel the plan with reason "User abort"
    Then the lifecycle plan processing state should be "cancelled"
    And the plan phase should remain "execute"

  Scenario: Re-execute after errored strategize is rejected
    Given I have a plan lifecycle service
    And I have a plan in strategize phase with processing state
    When strategize fails with error "Timed out"
    And I try to execute the errored plan
    Then a plan not ready error should be raised for the errored plan

  Scenario: Cannot complete strategize after it has been failed
    Given I have a plan lifecycle service
    And I have a plan in strategize phase with processing state
    When strategize fails with error "Network error"
    And I try to complete strategize after failure
    Then a plan error should be raised because plan is not processing