aegis -Develop_Begin(1)

NAME
aegis -Develop_Begin - begin development of a change

SYNOPSIS
aegis -Develop_Begin change-number [ option... ]
aegis -Develop_Begin -List [ option... ]
aegis -Develop_Begin -Help

DESCRIPTION
The aegis -Develop_Begin command is used to commence development of a change.

The development directory for the change will be created automatically; below the directory specified in the default_development_directory field of aeuconf(5), or if not set below the directory specified in the default_development_directory field of aepattr(5), or if not set below the current user's home directory. It is rare to need to know the exact pathname of the development directory, as the aecd(1) command can take you there at any time.

Successful execution of this command will move the specified change from the awaiting development state to the being developed state.

  Notification
The develop_begin_command in the project configuration file (see aepconf(5) for more information) will be run, if specified. This is run after the aegis locks are released, so additional aegis commands may be run from here, if used with care. The symbolic links (see below) have not yet been created.

  Development Directory Location
Please Note: Aegis also consults the underlying file system, to determine its notion of maximum file size. Where the file system's maximum file size is less than maximum_filename_length, the filesystem wins. This can happen, for example, when you are using the Linux UMSDOS file system, or when you have an NFS mounted an ancient V7 filesystem. Setting maximum_filename_length to 255 in these cases does not alter the fact that the underlying file systems limits are far smaller (12 and 14, respectively).

If your development directories (or your whole project) is on filesystems with filename limitations, or a portion of the heterogeneous builds take place in such an environment, it helps to tell Aegis what they are (using the project config file's fields) so that you don't run into the situation where the project builds on the more permissive environments, but fails with mysterious errors in the more limited environments.

If your development directories are routinely on a Linux UMSDOS filesystem, you would probably be better off setting dos_filename_required = true, and also changing the development_directory_template field. Heterogeneous development with various Windows environments may also require this.

ADMINISTRATOR OVERRIDE
It is possible for project administrators to use the -User option to force a developer to start developing a change. Some sites prefer to work this way. Note that developers still have the ability to use the aedbu(1) command.

Warning: capricious use of this command will rapidly alienate developers. The defaulting rules, particularly for the change number, depend on aegis and the developer agreeing on what the developer is currently working on.

The forced_develop_begin_notify_command project attribute (see aepattr(5) for more information) will be run when an administrator uses the -User option, in an attempt to minimize the surprises for developers. A suitable command is
    forced_develop_begin_notify_command =
        "$datadir/db_forced.sh $p $c $developer";
This command will send e-mail to the developer, informing her that the change has been assigned to her.

SYMBOLIC LINKS
Many dependency maintenance tools, and indeed some compilers, have little or no support for include file search paths, and thus for the concept of the two-level directory hierarchy employed by Aegis. (It becomes multi-level when Aegis' branching functionality is used.) To allow these tools to be used, Aegis provides the ability to maintain a set of symbolic links between the development directory of a change and the baseline of a project, so it appears to these tools that all of the project's files are present in the development directory.

  Project Configuration
The development_directory_style field of the project configuration file controls the appearance of the development directory. See aepconf(5) for more information.

By using a setting such as
    development_directory_style =
    {
        source_file_symlink = true;
        during_build_only = true;
    };
the user never sees the symbolic links, because they are added purely for the benefit of the dependency maintenance tool during the execution of the aeb(1) command.

By using a setting such as
    development_directory_style =
    {
        source_file_symlink = true;
    };
(the other will default to false) the symbolic links will be created at develop begin time (see aedb(1) for more information) and also maintained by each aeb(1) invocation. Note that the symbolic links are only maintained at these times, so project integrations during the course of editing change sourec files may leave the symbolic links in an inconsistent state until the next build.

When files are copied from the baseline into a change, using the aecp(1) command, the symbolic link pointing into the baseline, if any, will be removed before the file is copied.

Note: Using this functionality in either form has implications for how the rules file of the dependency maintenance tool is written. Rules must remove their targets before creating them (usually with an rm -f command) if you use any of the link sub-fields (both hard links and symbolic links). This is to avoid attempting to write the result on the symbolic link, which will point at a read-only file in the project baseline. This is similar to the same requirement for using the link_integration_directory field of the project configuration file.

  User Configuration
There is a symbolic_link_preference field in the user configuration file (see aeuconf(5) for more information). This controls whether aeb(1) will verify the symbolic links before the build (default) or whether it will assume they are up-to-date. (This field is only relevant if development_directory__style.source_file_symlink is true.)

For medium-to-large projects, verifying the symbolic links can take as long as the build itself. Assuming the symbolic links are up-to-date can be a large time-saving for these projects. It may be advisable to review your choice of DMT in such a situation.

The aedb(1) command does not consult this preference. Thus, in most situations, the symbolic links will be up-to-date when the build is performed. The only Aegis function which may result in the symbolic links becoming out-of-date is the integration of another change, as this may alter the presence or absence of files in the baseline. In this situation, the default aeb(1) action is to ignore the user preference and the verify symbolic links.

There are two command line options which modify aeb(1) behavior further: the -Verify-Symbolic-Links option says to verify the symbolic links; and the -Assume-Symbolic-Links option says to assume the symbolic links are up-to-date. In each case the option over-rides the default and the user preference.

It is possible to obtain behaviour similar to Tom Lord'a Arch by using a setting such as:
    development_directory_style =
    {
        source_file_link = true;
        source_file_symlink = true;
    };

It is possible to obtain behaviour similar to CVS by using a setting such as:
    development_directory_style =
    {
        source_file_copy = true;
    };
There are many more possible configurations of the development_directory_style, usually with helpful build side-effects. See aepconf(1) and the Depenedency Maintenance Tool chapter of the User Guide for more information.

The symbolic link command line options and preferences apply equally to hard links and file copies (the names have historical origins).

OPTIONS
The following options are understood:

-Change number
    This option may be used to specify a particular change within a project. See aegis(1) for a complete description of this option.

-DIRectory path
    This option may be used to specify which directory is to be used. It is an error if the current user does not have appropriate permissions to create the directory path given. This must be an absolute path.

    Caution: If you are using an automounter do not use `pwd` to make an absolute path, it usually gives the wrong answer.

-Help
    This option may be used to obtain more information about how to use the aegis program.

-List
    This option may be used to obtain a list of suitable subjects for this command. The list may be more general than expected.

-Project name
    This option may be used to select the project of interest. When no -Project option is specified, the AEGIS_PROJECT environment variable is consulted. If that does not exist, the user's $HOME/.aegisrc file is examined for a default project field (see aeuconf(5) for more information). If that does not exist, when the user is only working on changes within a single project, the project name defaults to that project. Otherwise, it is an error.

-REAson text
    This option may be used to attach a comment to the change history generated by this command. You will need to use quotes to insulate the spaces from the shell.

-TERse
    This option may be used to cause listings to produce the bare minimum of information. It is usually useful for shell scripts.

-User name
    This option is used to specify the user who is to develop the change. This option may only be used by a project administrator.

-Verbose
    This option may be used to cause aegis to produce more output. By default aegis only produces output on errors. When used with the -List option this option causes column headings to be added.

-Wait
    This option may be used to require Aegis commands to wait for access locks, if they cannot be obtained immediately. Defaults to the user's lock_wait_preference if not specified, see aeuconf(5) for more information.

-No_Wait
    This option may be used to require Aegis commands to emit a fatal error if access locks cannot be obtained immediately. Defaults to the user's lock_wait_preference if not specified, see aeuconf(5) for more information.

All options may be abbreviated; the abbreviation is documented as the upper case letters, all lower case letters and underscores (_) are optional. You must use consecutive sequences of optional letters.

All options are case insensitive, you may type them in upper case or lower case or a combination of both, case is not important.

For example: the arguments "-project, "-PROJ" and "-p" are all interpreted to mean the -Project option. The argument "-prj" will not be understood, because consecutive optional characters were not supplied.

Options and other command line arguments may be mixed arbitrarily on the command line, after the function selectors.

The GNU long option names are understood. Since all option names for aegis are long, this means ignoring the extra leading '-'. The "--option=value" convention is also understood.

RECOMMENDED ALIAS
The recommended alias for this command is
csh%	alias aedb 'aegis -db \!* -v'
sh$	aedb(){aegis -db "$@" -v}

ERRORS
It is an error if the change does not exist.
It is an error if the change is not in the awaiting development state.
It is an error if the current user is not a developer of the specified project.

EXIT STATUS
The aegis command will exit with a status of 1 on any error. The aegis command will only exit with a status of 0 if there are no errors.

ENVIRONMENT VARIABLES
See aegis(1) for a list of environment variables which may affect this command. See aepconf(5) for the project configuration file's project_specific field for how to set environment variables for all commands executed by Aegis.

SEE ALSO

aeb(1)
    build a change

aecd(1)
    change directory

aecp(1)
    copy files into a change

aed(1)
    find differences between a change and the baseline

aedbu(1)
    undo the effects of aedb

aede(1)
    complete development of a change

aemv(1)
    rename a file as part of a change

aenc(1)
    add a new change to a project

aend(1)
    add a new developer to a project

aenf(1)
    add new files to a change

aent(1)
    add a new test to a change

aepa(1)
    modify the attributes of a project

aerm(1)
    add files to be deleted to a change

aet(1)
    run tests

aepattr(5)
    project attributes file format

aeuconf(5)
    user configuration file format

COPYRIGHT
aegis version 4.24.D001
Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 20 Peter Miller

The aegis program comes with ABSOLUTELY NO WARRANTY; for details use the 'aegis -VERSion License' command. This is free software and you are welcome to redistribute it under certain conditions; for details use the 'aegis -VERSion License' command.

AUTHOR
Peter Miller | E-Mail: | millerp@canb.auug.org.au
/\/\* | WWW: | http://www.canb.auug.org.au/~millerp/