Wrapper Subflows
Wrapper Subflows
If you notice extra Run Subflow actions in your migrated PAD flow, this is expected. Subflows prefixed with "w" are Wrapper Subflows β Blueprint generates them to handle argument passing, which PAD does not support natively in subflow calls.
Why Wrapper Subflows Exist
Power Automate Desktop's Run Subflow action has no mechanism for passing arguments directly. When the source process requires argument passing between subflows, Blueprint creates wrapper subflows to handle it, ensuring the migrated flow behaves the same way as the original.
Wrapper subflows are only created when a subflow call passes more than five arguments. Calls with five or fewer arguments are handled inline β no wrapper is created.
What a Wrapper Subflow Does
A wrapper subflow runs immediately before the subflow it wraps. It performs three functions in sequence:
- Variable Initialization β Initializes internal variables from the source RPA tool. Variables with no default value are set to NULL.
- Argument Assignment β Assigns input and output argument values for the subflow call.
- Subflow Execution β Calls the target subflow as its final step.
If multiple calls share the exact same arguments, the same wrapper is reused rather than duplicated.
Naming Conventions
All wrapper subflow names begin with "w", followed by a prefix derived from the calling flow's name and then the called subflow's name.
Scenario | Prefix logic |
|---|---|
Main is the caller | No additional prefix β just "w" |
Called subflow name has multiple words separated by special characters | "w" + first 2β3 letters of each word |
Called subflow name is a single camelCase word | "w" + first 2β3 uppercase letters |
Called subflow name has one uppercase letter or is all lowercase | "w" + first 2β3 letters of the flow name |
Flow name starts with a special character or number | "w" + underscore added as prefix |
Examples:
Caller subflow | Called subflow | Wrapper name |
|---|---|---|
Subflow_A | Subflow_B | wSA_SubflowB |
subflow_a | subflow_b | wSA_SubflowB |
subflowa | subflowb | wSUB_subflowb |
Main | _5550 Subflow | w__5550 Subflow |
_5550_Main_Process | Extract_Data | wMP__Extract_Data |
β If the same caller subflow calls the same target subflow multiple times with different arguments, Blueprint creates a separate wrapper for each variation, distinguished by a numeric suffix β e.g., wSA_SubflowB, w1SA_SubflowB, w2SA_SubflowB.