About contributors

Before you perform a compare or merge operation, choose a range of files, called contributors, that will participate in the operation. Contributors are a group of related files (usually different versions or variants of the same XML document) whose changes you want to examine or merge.

The method that you use to select the contributors depends on how you run Rational® ClearCase® XML Diff Merge.

This topic describes the types of contributors and how XML Diff Merge uses them.

Base version

In a compare or merge operation, Rational ClearCase XML Diff Merge uses a base version (sometimes called the base contributor) to provide a common frame of reference for differences among the other contributor versions. That is, each contributor is compared, by itself, to the base version. Thus, each difference is a one-to-one comparison between a contributor and the base version.

When you use the command line or standalone XML Diff Merge to start a compare or merge operation, you must include a base version among the range of contributors. Frequently, the base version is a common ancestor version of all the contributors.

Tip: In the Open Contributors window, the file that you list first is treated as the base version.

By contrast, when you start a compare or merge operation using the ClearCase type manager, you do not explicitly select a base version; it is determined for you from the range of contributors that you select.

To-version

In an automatic merge, you can specify a merge policy that accepts changes only from a specific version to be included in the merge output. This is called the to-version. When you run Rational ClearCase XML Diff Merge through the ClearCase type manager, the to-version is the version selected by your view.

Tip: If you do not specify a to-version on the command line, the file that you list last in the Open Contributors window is treated as the to-version.

In ClearCase documentation, the term from-version sometimes refers to any contributor except the to-version. The term has no significance in XML Diff Merge except when the tool is started by using ClearCase functions.


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