What is struct-compare?

Struct Compare is a plugin for IDA Pro, a tool reverse engineers use to inspect and analyze compiled programs. This plugin adds a side by side comparison view for two structure or union type definitions inside IDA's Local Types database, so a user can see how two versions of a data structure differ. To use it, a person picks two structures, either by selecting both in the Local Types window or sending one at a time to a comparison window. The plugin opens two synced panes next to each other, with rows aligned by the byte offset of each field, so matching, differing, and unique members line up visually. Differences are shown with color: pink means a field exists on both sides but is different, green means a field only exists on one side, and no color means the field is identical on both. Beyond just viewing differences, the plugin lets a user merge fields from one structure into the other, with a preview of the generated C declaration before anything is written to the database. Merges go through IDA's own type parsing, so they can be undone. Fields can also be renamed, deleted, or retyped directly inside the comparison panes using the same keyboard shortcuts IDA normally uses in its own type editor, but only while a compare pane is active. If the underlying types change elsewhere, or the user performs an undo or redo, open comparison windows refresh automatically. Installing it means placing the plugin folder in IDA's plugins directory, or installing through IDA's HCLI package manager. It requires IDA Pro version 9.2 or later, running with its normal graphical interface rather than headless. The project is written in Python and is aimed at reverse engineers who work with IDA Pro's type system on a regular basis. It is released under the MIT license.