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UCM baseline name gets unexpected 4 digit extension



This technote explains a behavior in IBM Rational ClearCase where a UCM baseline does not get the exact name that is specified by the user.


When you make a new baseline in a stream that has foundations in multiple components, there can be naming conflicts.

ClearCase must generate a unique name for each baseline that is created, and will resolve any conflicts by generating and appending a four digit extension to the baseline name.

Note: ClearCase will make a best effort to reserve a basename for the top level baseline in a composite baseline hierarchy.

In some cases, it has been seen that the simple basename does not actually get used, but all baselines created get a four digit suffix.


Below is an explanation of why UCM Baseline names get unexpected 4 digit extensions:

CASE: Baseline name is supplied (MY_BASELINE) that is unique and does not yet exist. If the UCM stream contains more than one component, the config spec is used to determine what components should be scanned for changes. If a component is found to have changes and there are others to follow, the extension will be applied. This results from ClearCase not yet knowing if other components in the streams configuration require changes. If the Baseline is applied to the last possible Component in the config spec list, and is the only component that received the baseline, it will not receive a random 4 digit extension.

Resolving The Problem

This situation is avoidable if the project sets up a baseline name template with a convention that includes the component name in the baseline name.

Here is an example of setting the baseline name template to show the names that are generated:

  1. Update the baseline name template:

    cleartool> chproject -bln component,stream,date,time Enablement@\projects
    Changed baseline naming template for project "Enablement".

  2. Notice that the baseline names are specific to the component and do not contain the 4 digit extension, which is unique and unpredictable.

Review the following documentation for further details:
  • IBM Rational ClearCase Command Reference manual under the Modifying the baseline name template section of the chproject command (cleartool man chproject).

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Document Information

Modified date:
16 June 2018