C.4.2 Verifying log messages

Once you have entered a log message, you can evaluate that message to check for specific content, such as a bug ID. Use the verifymsg file to specify a program that is used to verify the log message. This program could be a simple script that checks that the entered message contains the required fields.

The verifymsg file is often most useful together with the rcsinfo file, which can be used to specify a log message template.

Each line in the verifymsg file consists of a regular expression and a command-line template. The template must include a program name, and can include any number of arguments. The full path to the current log message template file is appended to the template.

One thing that should be noted is that the ‘ALL’ keyword is not supported. If more than one matching line is found, the first one is used. This can be useful for specifying a default verification script in a directory, and then overriding it in a subdirectory.

If the repository name does not match any of the regular expressions in this file, the ‘DEFAULT’ line is used, if it is specified.

If the verification script exits with a non-zero exit status, the commit is aborted.

In the default configuration, CVS allows the verification script to change the log message. This is controlled via the RereadLogAfterVerify CVSROOT/config option.

When ‘RereadLogAfterVerify=always’ or ‘RereadLogAfterVerify=stat’, the log message will either always be reread after the verification script is run or reread only if the log message file status has changed.

See config, for more on CVSROOT/config options.

It is NOT a good idea for a verifymsg script to interact directly with the user in the various client/server methods. For the pserver method, there is no protocol support for communicating between verifymsg and the client on the remote end. For the ext and server methods, it is possible for CVS to become confused by the characters going along the same channel as the CVS protocol messages. See Remote repositories, for more information on client/server setups. In addition, at the time the verifymsg script runs, the CVS server has locks in place in the repository. If control is returned to the user here then other users may be stuck waiting for access to the repository.

This option can be useful if you find yourself using an rcstemplate that needs to be modified to remove empty elements or to fill in default values. It can also be useful if the rcstemplate has changed in the repository and the CVS/Template was not updated, but is able to be adapted to the new format by the verification script that is run by verifymsg.

An example of an update might be to change all occurrences of ’BugId:’ to be ’DefectId:’ (which can be useful if the rcstemplate has recently been changed and there are still checked-out user trees with cached copies in the CVS/Template file of the older version).

Another example of an update might be to delete a line that contains ’BugID: none’ from the log message after validation of that value as being allowed is made.

The following is a little silly example of a verifymsg file, together with the corresponding rcsinfo file, the log message template and an verification script. We begin with the log message template. We want to always record a bug-id number on the first line of the log message. The rest of log message is free text. The following template is found in the file /usr/cvssupport/tc.template.

BugId:

The script /usr/cvssupport/bugid.verify is used to evaluate the log message.

#!/bin/sh
#
#       bugid.verify filename
#
#  Verify that the log message contains a valid bugid
#  on the first line.
#
if sed 1q < $1 | grep '^BugId:[ ]*[0-9][0-9]*$' > /dev/null; then
    exit 0
elif sed 1q < $1 | grep '^BugId:[ ]*none$' > /dev/null; then
    # It is okay to allow commits with 'BugId: none',
    # but do not put that text into the real log message.
    grep -v '^BugId:[ ]*none$' > $1.rewrite
    mv $1.rewrite $1
    exit 0
else
    echo "No BugId found."
    exit 1
fi

The verifymsg file contains this line:

^tc     /usr/cvssupport/bugid.verify

The rcsinfo file contains this line:

^tc     /usr/cvssupport/tc.template

The config file contains this line:

RereadLogAfterVerify=always