aeclone

aegis -clone(1)                                                aegis -clone(1)



NAME
        aegis clone - make an exact copy of a change

SYNOPSIS
        aegis -CLone [ option...  ] change‐number [ change‐number ]
        aegis -CLone -Help
        aegis -CLone -VERSion

DESCRIPTION
        The aegis -CLone command is used to create exact replicas of changes.
        This is of most use when a change need to be applied to several
        parallel branches.

        One change number must be supplied.  This is the change to be
        replicated.  If any branch options are given (see below) the mandatory
        change number applies to the branch specified.  If no branch is
        specified, the change applies to the project (implicit or explicit).

        If the optional second change number is supplied, this is the change
        number to be created to hold the replica; if it is not supplied, the
        next available change number will be used.

        If the change to be replicated has been completed, the appropriate
        file revisions will be extracted from history; otherwise the files
        will be copied from the development directory of the change to be
        copied.  Be warned: if a file in the change which was cloned
        subsequently changes, those changes will not automagically be tracked.
        It is best if changes are cloned at a stable time, such as one of the
        states after develop end, or even after integrate pass.

   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.

WHITEOUT
        Aegis provides you with what is often called a “view path” which
        indicates to development tools (compilers, build systems, etc) look
        first in the development directory, then in the branch baseline, and
        so on up to the trunk baseline.

        The problem with view paths is that in order to remove files, you need
        some kind of "whiteout" to say “stop looking, it's been removed.”

        When you user the aerm(1) or aemv(1) commands, this means "add
        information to this change which will remove the file from the
        baseline when this change is integrated".  I.e. while the change is in
        the being developed state, the file is only "removed" in the
        development directory - it's still present in the baseline, and will
        be until the change is successfully integrated.

        When you use the aerm(1) or aemv(1) commands, Aegis will create a 1K
        file to act as the whiteout.  It's contents are rather ugly so that if
        you compile or include the "removed" file accidentally, you get a
        fatal error.  This will remind you to remove obsolete references.

        When the change in integrated, the removed file is not copied/linked
        from the baseline to the integration directory, and is not copied from
        the development directory.  At this time it is physically gone (no
        whiteout).  It is assumed that because of the error inducing whiteout
        all old references were found and fixed while the change was in the
        being developed state.

   File Manifests
        When generating list of files to be compiled or linked, it is
        important that the file manifest be generated from information known
        by Aegis, rather than from the file system.  This is for several
        reasons:

        (a) Aegis knows exactly what (source) files are where, whereas
            everything else is inferring Aegis' knowledge; and

        (b) looking in the file system is hard when the view path is longer
            that 2 directories (and Aegis' branching method can make it
            arbitrarily long); and

        (c) The whiteout files, and anything else left “lying around”, will
            confuse any method which interrogates the file system.

        The easiest way to use Aegis' file knowledge is with something like an
        awk(1) script processing the Aegis file lists.  For example, you can
        do this with make(1) as follows:
                # generate the file manifest
                manifest.make.inc: manifest.make.awk
                    ( aegis -l cf -ter ; aegis -l pf -ter ) | \
                    awk -f manifest.make.awk > manifest.make.inc
                # now include the file manifest
                include manifest.make.inc
        Note: this would be inefficient of you did it once per directory, but
        there is nothing stopping you writing numerous assignments into the
        manifest.make.inc file, all in one pass.

        It is possible to do the same thing with Aegis' report generator (see
        aer(1) for more information), but this is more involved than the
        awk(1) script.  However, with the information "straight from the
        horse's mouth" as it were, it can also be much smarter.

        This file manifest would become out‐of‐date without an interlock to
        Aegis' file operations commands.  By using the project‐file_command
        and change_file_command fields of the project config file (see
        aepconf(5) for more information), you can delete this file at
        strategic times.
                /* run when the change file manifest is altered */
                change_file_command = "rm -f manifest.make.inc";
                /* run when the project file manifest is altered */
                project_file_command = "rm -f manifest.make.inc";
        The new file manifest will thus be re‐built during the next aeb(1)
        command.

   Options and Preferences
        There is a -No‐WhiteOut option, which may be used to suppress whiteout
        files when you use the aerm(1) and aemv(1) commands.  There is a
        corresponding -WhiteOut option, which is usually the default.

        There is a whiteout_preference field in the user preferences file (see
        aeuconf(5) for more information) if you want to set this option more
        permanently.

   Whiteout File Templates
        The whiteout_template field of the project config file may be used to
        produce language‐specific error files.  If no whiteout template entry
        matches, a very ugly 1KB file will be produced - it should induce
        compiler errors for just about any language.

        If you want a more human‐readable error message, entries such as
                whiteout_template =
                [
                    {
                        pattern = [ "*.[ch]" ];
                        body = "#error This file has been removed.";
                    }
                ];
        can be very effective (this example assumes gcc(1) is being used).

        If it is essential that no whiteout file be produced, say for C source
        files, you could use a whiteout template such as
                whiteout_template =
                [
                    { pattern = [ "*.c" ]; }
                ];
        because an absent body sub‐field means generate no whiteout file at
        all.

        You may have more than one whiteout template entry, but note that the
        order of the entries is important.  The first entry which matches will
        be used.

   Notification
        The notification commands that would be run by the aecp(1), aedb(1),
        aenf(1), aent(1) and aerm(1) commands are run, as appropriate.  The
        project_file_command is also run, if set.  See aepconf(5) for more
        information.

Cloning and Merging
        When you use aeclone(1) to clone a change set, and then integrate one
        of the two change sets, you will observe that Aegis says that the
        files of the un‐integrated change are now out‐of‐date.

        If you run aem(1) to bring the out‐of‐date files back up‐to‐date,
        fmerge(1) and some (but not) all other merging tools, it signals just
        about everything as a conflict, even though both alternatives are
        identical.

        The problem is that two changes making identical edits to the same
        place in the same file are a logical conflict, even if not an actual
        conflict, and it takes a human to figure out the difference.  Think of
        a shopping list: the ensuite needs more soap, and so does the main
        bathroom.  The second "soap" on the merge of the two shopping lists
        isn't a duplicate, you really do need two boxes of soap.  Sometimes
        edits of source files are the same: sometimes the logical conflict is
        resolved by applying both identical edits, not just one.

        This is just the fmerge(1) command being more conservative than RCS's
        merge(1) command.

        The easiest way to deal with this common situation it to run an
                aecpu -unchanged
        command before you run the aem(1) merge command, and you will have
        less grief.  It's also worth remembering that Aegis stashes the
        original file with a ,B suffix (B for backup) so you can simply
                mv fubar,B fubar
        if you know that all of the conflicts are logical conflicts.

OPTIONS
        The following options are understood:

        -BRanch number
                This option may be used to specify a different branch for the
                origin file, rather than the baseline.  (See also -TRunk
                option.  Please Note: the -BRanch option does not take a
                project name, just the branch number suffix.

        -GrandParent
                This option may be used to specify the grandparent branch (one
                up from the current branch) for the origin file, rather than
                the baseline.  (The -grandparent option is the same as the
                “-branch ..” option.)

        -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.

        -WhiteOut
                This option may be used to request that deleted files be
                replaced by a “whiteout” file in the development directory.
                The idea is that compiling such a file will result in a fatal
                error, in order that all references may be found.  This is
                usually the default.

        -No_WhiteOut
                This option may be used to request that no “whiteout” file be
                placed in the development directory.

        -Output filename
                This option may be used to specify a filename which is to be
                written with the automatically determined change number.
                Useful for writing scripts.

        -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.

        -TRunk
                This option may be used to specify the project trunk for the
                origin file, rather than the baseline.  (See also -BRanch
                option, the -trunk option is the same as the “-branch -”
                option.)

        -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.

        See also aegis(1) for options common to all aegis commands.

        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.

ERRORS
        It is an error if the current user is not an administrator of the
        project.  (In some cases it is possible for developers of a project to
        create changes, see aepattr(5) for more information.)

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
        aenc(1) Create a new change.

        aeca(1) modify the attributes of a change

        aena(1) add a new administrator to a project

        aepa(1) modify the attributes of a project

COPYRIGHT
        aegis version 4.25.D510
        Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
        2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
        2011, 2012 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:   pmiller@opensource.org.au
        /\/\*             WWW:   http://miller.emu.id.au/pmiller/



Reference Manual                     Aegis                     aegis -clone(1)