Integrating incremental analysis with version management

Abstract

In an interactive software development environment, incremental algorithms are used to restore consistency to structured, annotated documents after they have been modified. Versioning expresses the relationship of a document's content to its modification history. We present a means of integrating these formerly separate concerns; the analyses and transformations used both for updates and for consistency restoration are implemented using a fine-grained model of object versioning.

We treat software artifacts as graph-structured documents. Both the contents and annotations on the document can be of diverse media. We describe extensions to conventional incremental algorithms for analyzing such documents, and explain how the ability to name and access different versions of the document simultaneously simplifies these algorithms. Our design maximizes component preservation to avoid losing auxiliary information important to the user.

Making the primary distribution of update information spatial rather than temporal supports object-oriented change modeling as well as implementations customized for specific media. All clients—presentation services, analyzers, code generators, and external tools—use a single uniform interface to history information. The time to access any version of an atomic component is linear in the number of subsequent changes to that component; the time to explore structured components is O(lg(¦nodes ¦) * ¦changed set ¦). We discuss an implementation of these concepts in a working environment.

This research was supported in part by Advanced Research Projects Agency grant MDA972-92-J-1028, and by NSF grant CDA-8722788. The content of this paper does not necessarily reflect the position or the policy of the U. S. Government.