config_spec

Rules for selecting versions of elements to appear in a view

APPLICABILITY

ClearCase (data structure)

SYNOPSIS

• Standard Rule:

  scope pattern version-selector [ optional-clause ]

• Create Branch Rule:

  mkbranch branch-type-name [ -override ]
  ...
  [ end mkbranch [ branch-type-name ] ]

• Time Rule:

  time date-time
  ...
  [ end time [ date-time ] ]

• File-Inclusion Rule:

  include config-spec-pname

• Load Rule (for snapshot views):

  load pname ...

DESCRIPTION

A view's config spec (configuration specification) contains an ordered set of rules for selecting versions of ClearCase elements. The view's associated view_server process populates a view with versions by evaluating the config spec rules.

In a dynamic view, version selection is dynamic. Each time a reference is made to a file or directory element-either by ClearCase software or by standard programs-the view_server uses the config spec to select a particular version of the element. (In practice, a variety of caching techniques and optimizations reduce the computational requirements.)

In a snapshot view, users invoke an update operation to select versions from the VOB.

Config Spec Storage / Default Config Spec

Each view is created with a copy of the systemwide default config spec, ccase-home-dir\default_config_spec:

Modifying this file changes the config spec that newly created views receive, but does not affect any existing view.

An individual view's config spec is stored in its view storage directory, in two forms:

• Source format - The user-visible version, config_spec, contains only the series of config spec rules.
• Compiled format - A modified version, .compiled_spec, includes ClearCase accounting information. This version is created and used by the view_server process.

Do not modify either of these files directly; instead, use the commands listed below. Different views' config specs are independent: they may contain the same set of rules, but changing one view's config spec never affects any other view.

Commands for Maintaining Config Specs

ClearCase commands for manipulating config specs:

You can edit a config spec on the Config Spec tab in the Properties of View Browser or during view creation with the View Creation Wizard.

HOW A CONFIG SPEC SELECTS VERSIONS

The set of elements considered for version selection is different for the two kinds of views:

• In a dynamic view, all elements in VOBs mounted on the current host are considered for version selection.
• In a snapshot view:
  • If you are updating a loaded element, the behavior is the same as in a dynamic view and the selected version is loaded into the view.
  • If you are not updating and the element is loaded, the selection from the last update is used.
  • If the element isn't loaded at all, the behavior is the same as in a dynamic view.

For each element, the following procedure determines which version, if any, is in the view.

1. The view's associated view_server process tries to find a version of the element that matches the first rule in the config spec:
   • If such a version exists, that version is in the view.
   • If multiple versions match the rule, an error occurs, and no version of the element is in the view. ClearCase commands that access the element print errors like this one:

     cleartool: Error: Trouble looking up element "ht.c" in directory ".".

   Standard commands that access the element print errors like this one:

   The request could not be performed because of an I/O device error.

   • If no version matches the first rule, the search continues.
2. If no matching version was found for the first rule, the view_server tries to find a version that matches the second rule.
3. The view_server continues in this way until it finds a match or until it reaches the last rule.

Order Is Important

Because the rules in a config spec are processed in order, varying the order may affect version selection. For example, suppose this rule appears near the beginning of a config spec:

element * \main\LATEST

Any subsequent rules in the config spec will never be used, because the rule will always provide a match; every element has a most-recent version on its main branch.

NOTE: The order in which the load rules for a snapshot view are specified is not important.

CHECKEDOUT Rule for Snapshot Views

The config spec for a snapshot view must contain element * CHECKEDOUT as the first element rule.

Failure to Select Any Version

If no version of an element matches any rule in the config spec:

• In a dynamic view:
  • The element's data is not accessible through the view. The standard dir command and other standard programs print a not found error when attempting to access the element.
  • The ClearCase ls command lists the element with a [no version selected] annotation. You can specify the element in commands that access the VOB database only, such as describe, lsvtree, and mklabel.
• In a snapshot view, the element will not be loaded.

View-Private Files

A view's config spec has no effect on the private objects in a view, such as view-private files, links, directories; or, in the case of a dynamic view, derived objects. View-private objects are always accessible.

Exception: (Dynamic views only) If a config spec lacks a CHECKEDOUT rule, the view-private file that is a file element's checked-out version is not visible. See Special Version Selectors below.

OVERALL SYNTAX GUIDELINES

Each config spec rule must be contained within a single physical text line; you cannot use a caret (^) or other line continuation character to continue a rule onto the next line. Multiple rules can be placed on a single line, separated by semicolon (;) characters.

Lines that begin with a number sign (#) are comments.

Extra white space (SPACE, TAB, vertical-tab, and form-feed) characters are ignored, except within the version selector. If a version selector includes white space, enclose it in single quotes.

If a load rule specifies a file or directory name that includes one or more SPACE characters, you must enclose the entire pathname in either single-quotes (`) or double quotes (").

In general, VOBs, views, and the ClearCase tools that access them are case-sensitive. Therefore, config spec rules must use case-correct pathnames.

You can use slashes ( / ) or backslashes ( \ ) as pathname separators in pathname patterns and version selectors unless you are sharing the config spec between UNIX and Windows hosts. In that case, you must use slashes. (See SHARING CONFIG SPECS BETWEEN UNIX AND WINDOWS HOSTS.)

SHARING CONFIG SPECS BETWEEN UNIX AND WINDOWS HOSTS

Windows and UNIX ClearCase clients can share config specs, which are portable between the two operating systems. That is, clients on both systems, using views whose storage directories reside on either kind of host, can set and edit the same set of config specs. However, Windows and UNIX network regions often use different VOB-tags to register the same VOBs. Only single-component VOB-tag names, like \src2vob, are permitted on Windows clients; multiple-component VOB-tags, like /vobs/src/proj1, are common on UNIX. When the VOB-tags diverge between regions, config spec element rules that use full pathnames (which include VOB-tags) are resolvable (at config spec compile time) only by hosts in the applicable network region. This implies a general restriction regarding shared config specs: a given config spec must be compiled only by hosts on one operating system or the other-the operating system for which full pathnames in element rules make sense. That is, a config spec with full pathnames can be shared across network regions, even when VOB-tags disagree, but it must be compiled in the right place.

This restriction does not apply if any of the following are true:

• The config spec's element rules use relative pathnames only, which do not include VOB-tags.
• Shared VOBs are registered with identical, single-component VOB-tags in both Windows and UNIX network regions. (The VOB-tags \r3vob and /r3vob are logically identical, differing only in their leading slash characters.)
• The config spec does not include any load rules or element rules.

Config Spec Compilation

An in-use config spec exists in both text file and compiled formats (both of which are visible in the view's storage directory). A config spec in its compiled form is portable. The restriction is that full VOB pathnames in element rules must be resolvable at compile time. A config spec is compiled if a client executes either of these cleartool commands: edcs or setcs -current. Therefore, if a client on the "wrong" operating system recompiles a config spec with one of these commands, the config spec becomes unusable by any client using that view. If this happens, simply recompile the config spec on the "right" operating system.

A sample element rule that could be problematic:

element /vob_p2/src/*    /main/rel2/LATEST

If the VOB is registered with VOB-tag \vob_p2 on a Windows network region, but with VOB-tag /vobs/vob_p2 on a UNIX network region, only Windows ClearCase clients can compile the config spec.

Pathname Separators

When writing config specs to be shared by Windows and UNIX ClearCase clients, use the slash (/), not the backslash (\), as the pathname separator in pathname patterns and version selectors. ClearCase on Windows can parse either separator in pathnames; ClearCase on UNIX recognizes / only.

STANDARD RULES

A standard version-selection rule takes this form:

scope pattern version-selector [ optional-clause ]

The following subsections describe these components.

Scope

The scope specifies that the rule applies to all elements, or restricts the rule to a particular type of element.

element

The rule applies to all elements.

element -file

The rule applies to file elements only. This includes any element created with a mkelem command that omits -eltype directory (or a user-defined element type derived from directory).

element -directory

The rule applies to directory elements only. This includes any element created with mkdir or mkelem -eltype directory (or a user-defined element type derived from directory).

element -eltype element-type

The rule applies only to elements of the specified element type (predefined or user-defined). This mechanism is not hierarchical: if element type aaa is a supertype of element type bbb, the scope element -eltype aaa does not include elements whose type is bbb. To specify multiple element types, you must use multiple rules:

element -eltype aaa * RLS_1.2
element -eltype bbb * RLS_1.2

Selecting Versions of VOB Symbolic Links. There is no VOB symbolic link scope. A VOB symbolic link is cataloged (listed) in one or more versions of a directory element. The link appears in a view if both of these conditions are true:

• One of those directory versions is selected by the view's config spec.
• The config spec includes any element rule, even a -none rule.

Pattern

A pathname pattern, which can include any ClearCase wildcard (see the wildcards_ccase reference page for a complete list). For example:

*

Matches all element pathnames; does not match recursively.

*.c

Matches all element pathnames with a .c extension.

src\util.c

Matches any element named util.c that resides in any directory named src.

\vob6\include\util.h

Matches one particular element.

src\...\util.c

Matches any element named util.c that resides anywhere within the subtree of a directory named src (including in src itself).

src\...\*.c

Matches all elements with a .c extension located in or below any directory named src.

src\...

Matches the entire directory tree (file elements and directory elements) starting at any directory named src.

NOTE: In non-config-spec contexts, the ... pattern matches directory names only.

Restrictions:

• A view-extended pathname pattern is not valid.
• A relative pathname pattern must start below the VOB-tag (VOB mount point, VOB root directory). For example, if the VOB-tag is \src3, src3\include\utility.h is not a valid pattern.
• A full pathname pattern must specify a location at or beneath a valid VOB-tag. For example, if the VOB-tag is \src3, then \src3\... and \src3\include\... are both valid.

  The setcs or edcs command fails if it encounters an invalid location in any config spec rule:

cleartool: Error: No registered VOB tag in path: "..."

• VOB symbolic links are not valid in pathname patterns.
• Patterns can be specified using either backslashes (\) or slashes (/).

Version Selector

You can use a version label, version-ID, or any other standard ClearCase version selector. See the version_selector reference page for a complete list. Some examples follow:

\main\4

Version 4 on an element's main branch.

REL2

The version to which version label REL2 has been attached. An error occurs if more than one version of an element has this label.

...\mybranch\LATEST

The most recent version on a branch named mybranch; this branch can occur anywhere in the element's version tree.

\main\REL2

The version on the main branch to which version label REL2 has been attached.

{created_since(yesterday)}

The version that has been created since yesterday. An error occurs if more than one version satisfies this query. Because all queries are evaluated at run time, the value yesterday is always interpreted relative to the day that the query is executed.

{QA_Level>3}

The version to which attribute QA_Level has been attached with a value greater than 3. An error occurs if more than one version satisfies this query.

...\mybranch\{QA_Level>3}

The most recent version on a branch named mybranch satisfying the attribute query.

Standard version selectors cannot select checked-out versions in a config spec rule. (They can in other ClearCase contexts, such as the find command.) Instead, you must use the special version selector, CHECKEDOUT, described below.

Special Version Selectors. The following special version selectors are valid only in a config spec rule, not in any other ClearCase version-selection context:

CHECKEDOUT

Matches the checked-out version of an element, if this view has a pending checkout. It doesn't matter where (on which branch of the element) the checkout occurred; there is no possibility of ambiguity, because only one version of an element can be checked out to a particular view.

This special version selector actually matches the checked-out version object in the VOB database, which is created by the checkout command.

For file elements, standard commands access the view-private file created by checkout at the same pathname as the element.

-config do-pname [ -select do-leaf-pattern ] [ -ci ]

This special version selector replicates the configuration of versions used in a particular clearmake build. It selects versions listed in one or more configuration records associated with a particular derived object: the same set of versions that would be listed by a catcr -flat command. See the catcr reference page for explanations of the specifications that follow the -config keyword.

When you set or edit a config spec, the view_server resolves the do-pname with respect to the view's preexisting config spec, not on the basis of any preceding rules in the config spec being evaluated.

If the configuration records list several versions of the same element, the most recent version is selected to appear in the view. In such cases, a warning message is displayed when the config spec is set.

-none

Generates an ENOENT (No such file or directory) error when a standard UNIX operating system program references the element. For dynamic views:

-error

Like -none, except that the annotation generated by the cleartool ls command is error on reference.

Optional Clause

Some config spec rules can include an additional clause, which modifies the rule's meaning.

-time date-time

Modifies the meaning of the special version label LATEST: the rule selects from a branch the last version that was created before a particular time. The date-time argument is specified in one of the standard ClearCase formats:

date.time | date | time | now
where:

Specify time in 24-hour format, relative to the local time zone. If you omit the time, the default value is 00:00:00. If you omit date, the default is today. If you omit the century, year, or a specific date, the most recent one is used. Specify UTC if you want ClearCase to resolve the time to the same moment in time regardless of time zone. Use the plus (+) or minus (-) operator to specify a positive or negative offset to the UTC time. If you specify UTC without hour or minute offsets, Greenwich Mean Time (GMT) is used. (Dates before January 1, 1970 Universal Coordinated Time (UTC) are invalid.)

The creation times of the versions on the branch are looked up in their create version event records. (No error occurs if you use a -time clause in a rule that does not involve the version label LATEST; the clause has no effect.)

The -time clause in a particular rule overrides any general time rule currently in effect. (See TIME RULES.)

Restriction: -time must precede any other optional clauses.

Examples:

The date/time specification is evaluated when you set or edit the config spec, and whenever the view_server process is started (for example, with startview or setview (dynamic views only)). Thus, the meaning of a relative specification, such as today, may change over time. However, the date/time is not evaluated at run time. Therefore if you last performed one of the commands listed above four days ago, the meaning of a relative specification, such as today, has the value of the date four days ago, not the value of the date today.

-nocheckout

Disables checkouts of elements selected by the rule.

-mkbranch branch-type-name

Implements ClearCase auto-make-branch facility. When a version selected by this rule is checked out:

(This is a slight oversimplification. See Multiple-Level Auto-Make-Branch.) A mkelem command invokes the auto-make-branch facility if the config spec includes a \main\LATEST rule with a -mkbranch clause.

Restrictions: You cannot use -mkbranch in combination with -none or -error.

Multiple-Level Auto-Make-Branch

A config spec can include a cascade of auto-make-branch rules, causing checkout to create multiple branching levels at once. checkout keeps performing auto-make-branch until version 0 on the newly created branch is not selected by a rule with a -mkbranch clause; then, it checks out that version. For example:

If you check out an element in a view that currently selects the version labeled MYLABEL:

1. A branch of type br1 is created at the MYLABEL version (Rule (4)).
2. Rule (3) now selects the newly created version ...\br1\0, so a branch of type br2 is created at that version.
3. Version ...\br1\br2\0 is checked out. The checked-out version has the same contents as the MYLABEL version, and is selected by Rule (1). When you edit and check in a new version, ...\br1\br2\1, the view will select it with Rule (2).

CREATE BRANCH RULES

A create branch rule takes the following form:

mkbranch branch-type-name [ -override ]
<config spec lines>
[ end mkbranch [ branch-type-name ] ]

This rule is similar to the -mkbranch clause; use it when you want to add a -mkbranch clause to many lines in a complex config spec.

mkbranch branch-type-name [ -override ]

Attaches an implicit -mkbranch branch-type-name clause to all element rules between mkbranch and end mkbranch (or the end of the file) that do not have a -mkbranch clause or include the CHECKEDOUT version selector.

Specifying -override will override any explicit -mkbranch clauses or mkbranch rules within the scope and replace them with -mkbranch branch-type-name. Use -override if you do not want multilevel branch creation.

end mkbranch [ branch-type-name ]

Ends the mkbranch branch-type-name rule. If end mkbranch is omitted, the rule is ended at the end of the config spec. The branch-type-name argument is optional, but if you include it, it must match the branch type specified with the mkbranch rule.

mkbranch and end mkbranch rules may be nested. For example:

element * .../branch2/LATEST
mkbranch branch2

element * .../branch1/LATEST
mkbranch branch1

element * /main/LATEST

end mkbranch branch1
end mkbranch branch2

Checking out foo.c creates foo.c@@/main/branch1/branch2/CHECKEDOUT. This is a multiple-level mkbranch.

TIME RULES

A time rule takes this form:

time date-time
[ end time [ date-time ] ]

It is analogous to the optional -time clause. A time rule modifies the meaning of the special version label LATEST in subsequent rules, with the following exceptions:

• An optional -time clause in a particular rule overrides any general time rule currently in effect.
• A subsequent time rule cancels and replaces an earlier one.

Use end time to limit the effect of a time rule to a certain range. The date-time argument is optional with end time, but if you include it, it must match the date-time argument specified with the time rule.

Time rules may be nested.

The date-time specification is evaluated when you set or edit the config spec, and whenever the view_server process is started (for example, with startview or setview (dynamic views only)). Thus, the meaning of a relative specification, such as today, may change over time. However, the date-time is not evaluated at run time. So if you last performed one of the commands listed above four days ago, the meaning of a relative specification, such as today, has the value of the date four days ago, not the value of the date today.

FILE-INCLUSION RULES

A file-inclusion rule takes this form:

include config-spec-pname

The argument specifies a text file containing one or more config spec rules (possibly other include rules). Include files are reread on each execution of setcs and edcs. A file-inclusion rule must be the last rule in a line. For example,

include config-spec-pname

and

time date-time; include config-spec-pname

are both valid.

LOAD RULES

Load rules define which elements are loaded (copied) into a snapshot view (by contrast, element rules define which version of an element is selected). A load rule takes this form:

load pname ...

The argument specifies one or more file or directory elements. Naming a directory element implies the directory and all elements below the directory. Naming a file element specifies that element only.

More than one load rule can appear in a config spec; you must have at least one to see any files in a snapshot view. (Load rules in the config spec of a dynamic view are ignored.)

Load rules can be positioned anywhere in a config spec, and their order is irrelevant.

An element can be selected by more than one load rule without causing an error.

VOB links (both symbolic links and hard links) are followed, and the link target is copied into the snapshot view at the location in which the link appeared.

EXAMPLES

• Include a standard set of rules to be used by every user on a particular project.

include \proj\cspecs\v1_bugfix_rules

• Modify the meaning of "most recent" to mean "as of 7 P.M. on July 10."

time 10-Jul.19:00
    element \atria\lib\* ...\new\LATEST
    element * \main\LATEST
end time

• Select version 3 on the main branch of a particular header file.

element \proj1\include\utility.h \main\3

• Select the most recent version on the main branch for all elements with a .c file-name extension.

element *.c \main\LATEST

• Select the most recent version on the bugfix branch.

element * ...\bugfix\LATEST

• Select versions of elements from a particular development branch, or with a related label.

  element * CHECKEDOUT element * ...\maint\LATEST	(If no checked-out version, select latest version on the 'maint' branch, which may or may not be a direct subbranch of main)
  element * BL2.6	(Else, select version labeled 'BL2.6' from any branch)
  element * \main\LATEST

• Select versions of C language source files (.c file extension) based on the value of an attribute. A config spec such as this may be used by a developer to select versions of files for which he is responsible.

  element * CHECKEDOUT
  element -file *.c \main\{RESPONSIBLE=="jpb"}	(For any '.c' file, select latest version on main branch for which 'jpb' is responsible)
  element -file \project\utils\...\*.c \main\BL2.6	(Else, select version labeled BL2.6 on main branch from \project\utils directory, or any of its subdirectories)
  element * \main\LATEST

• Use the -mkbranch qualifier to create a new BL3 branch automatically. Create the branch off the version labeled BL2.6, or the latest version on the main branch if no version is labeled BL2.6.

  element * CHECKEDOUT element * ...\bl3_bugs\LATEST	(If no version is checked out, select latest version on 'bl3_bugs' branch)
  element -file * BL2.6 -mkbranch bl3_bugs	(Else, select version labeled 'BL2.6' and create 'bl3_bugs' branch on checkout)
  element -file * \main\LATEST -mkbranch bl3_bugs	(Else, select latest version on main branch and create new branch on checkout)

• Same as above, but use a mkbranch rule.

element * CHECKEDOUT
element * ...\bl3_bugs\LATEST
mkbranch bl3_bugs
element -file * BL2.6
element -file * \main\LATEST
end mkbranch bl3_bugs

• Select the version labeled REL3 for all elements, preventing any checkouts to this view:

element * REL3 -nocheckout

• Select the most recent version on the bug_fix_v1.1.1 branch, making sure that this branch is a subbranch of bug_fix_v1.1, which is itself a subbranch of bug_fix_v1.

element * CHECKEDOUT
element * bug_fix_v1.1.1\LATEST
element * ...\bug_fix_v1.1\LATEST -mkbranch bug_fix_v1.1.1
element * ...\bug_fix_v1\LATEST -mkbranch bug_fix_v1.1
element * \main\LATEST -mkbranch bug_fix_v1

When a user checks out an element for which none of these branches yet exists, a cascade of
auto-make-branch activity takes place:

Z:\myvob> cleartool checkout -nc .

Created branch "bug_fix_v1" from "." version "\main\0".
Created branch "bug_fix_v1.1" from "." version "\main\bug_fix_v1\0".
Created branch "bug_fix_v1.1.1" from "." version "\main\bug_fix_v1\bug_fix_v1.1\0".
Checked out "." from version "\main\bug_fix_v1\bug_fix_v1.1\bug_fix_v1.1.1\0".

• Modify the previous config spec to create branch bug_fix_v2 off an existing branch rather than creating multiple subbranches.

element * CHECKEDOUT
mkbranch bug_fix_v2 -override
element * bug_fix_v1.1.1\LATEST
element * ...\bug_fix_v1.1\LATEST -mkbranch bug_fix_v1.1.1
element * ...\bug_fix_v1\LATEST -mkbranch bug_fix_v1.1
element * \main\LATEST -mkbranch bug_fix_v1
end mkbranch bug_fix_v2

• For a snapshot view, select the most recent version on the main branch. Use load rules to select in the applets VOB all elements below the \cmdlg directory and one specific element in the \testdlg directory.

element * CHECKEDOUT
element *... \main\LATEST
load \applets\cmdlg
load \applets\testdlg\opendlg.h

FILES

ccase-home-dir\default_config_spec
view-storage-directory\config_spec
view-storage-directory\.compiled_spec

SEE ALSO

catcs, checkout, checkin, edcs, ls, mkbranch, setcs, setview, version_selector, view, view_server