PhpStorm 8.0.2 Help

Change Signature

In this section:


The Change Signature refactoring combines several different modifications that can be applied to a function signature. You can use this refactoring for the following purposes:

  • To change the function name.
  • To add new parameters and remove the existing ones.
  • To assign default values to the parameters.
  • To reorder parameters.
  • To change parameter names.
  • To propagate new parameters through the function call hierarchy.

When changing a function signature, PhpStorm searches for all usages of the function and updates all the calls, implementations, and overridings of the function that can be safely modified to reflect the change.

Default value and propagation of new parameters

For each new parameter added to a function, you can specify its default value (or an expression) in the Default field.

You can also propagate the parameters you have introduced to the functions that call the function whose signature you are changing.

The refactoring result depends on whether you specify the default value and whether you use propagation.

Propagation. New parameters can be propagated to any function that calls the function whose signature you are changing. In such case, generally, the signatures of the calling functions change accordingly. These changes, however, also depend on the default values set for the new parameters.

Default value. Generally, this is the value to be added to the function calls.

If the new parameter is not propagated to a calling function, the calls within such function will also use this value.

If the propagation is used, this value won't matter for the function calls within the calling functions.


The following table shows 3 different ways of performing the same Change Signature refactoring.

In all the cases, the function result() is renamed to generate_result() and a new parameter input is added to this function.

The examples show how the function call, the calling function (show_result()) and other code fragments may be affected depending on the refactoring settings.

Before After

To change a function signature

  1. In the editor, place the cursor within the name of the function whose signature you want to change.
  2. Do one of the following:
    • Press Ctrl+F6.
    • Choose Refactor | Change Signature on the main menu.
    • Choose Refactor | Change Signature on the context menu.
  3. In the Change Signature dialog, make the necessary changes to the function signature and specify which other, related, changes are required.

    You can:

    • Change the function name. To do that, edit the text in the Name field.
    • Manage the function parameters using the table and the buttons in the Parameters area:
      • To add a new parameter, click add and specify the properties of the new parameter in the corresponding table row.

        When adding parameters, you may want to propagate these parameters to the functions that call the current function.

      • To remove a parameter, click any of the cells in the corresponding row and click delete.
      • To reorder the parameters, use the arrowUp and arrowDown buttons. For example, if you wanted to put a certain parameter first in the list, you would click any of the cells in the row corresponding to that parameter, and then click arrowUp the required number of times.
      • To change the name or the default value of a parameter, make the necessary updates in the table of parameters (in the fields Name and Default value respectively).
    • Propagate new method parameters (if any) along the hierarchy of the functions that call the current function.

      (There may be functions that call the function whose signature you are changing. These functions, in their turn, may be called by other functions, and so on. You can propagate the changes you are making to the parameters of the current function through the hierarchy of calling functions and also specify which calling functions should be affected and which shouldn't.)

      To propagate a new parameter:

      1. Click the Propagate Parameters button propagateParameters or press Alt+G.
      2. In the left-hand pane of the Select Methods to Propagate New Parameters dialog, expand the necessary nodes and select the check boxes next to the functions you want the new parameters to be propagated to.

        To help you select the necessary functions, the code for the calling function and the function being called is shown in the right-hand part of the dialog (in the Caller Method and Callee Method panes respectively).

        As you switch between the functions in the left-hand pane, the code in the right-hand pane changes accordingly.

      3. Click OK.
  4. To perform the refactoring right away, click Refactor.

    To see the expected changes and make the necessary adjustments prior to actually performing the refactoring, click Preview.

See Also

Last modified: 29 January 2015