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Rules for selecting versions of elements to appear in a view
A view's config spec (configuration specification) contains an ordered set of rules for selecting versions of elements. The view's associated view_server process populates a view with versions by evaluating the config spec rules. For more information about view_server , see the IBM Rational ClearCase Administrator's Guide .
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.
UCM config specs are different from those for base ClearCase and base ClearCase LT in that their rules are generated, not user-specified; read UCM config specs before reading any other section of this reference page.
Each view is created with a copy of the default config spec, default_config_spec :
element * CHECKEDOUT |
For any element, select the checked out version, if any) |
element * /main/LATEST |
Otherwise, select most recent version on the main branch |
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:
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 manipulating config specs:
catcs |
Lists a view's config spec |
setcs |
Makes a specified file a view's config spec |
edcs |
Revises the current config spec of a view |
update –add_loadrules |
Adds load rules to the config spec of a snapshot view while updating the view |
The set of elements considered for version selection is different for the two kinds of views:
For each element, the following procedure determines which version, if any, is in the view.
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.
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 always provides a match; every element has a most recent version on its main branch.
The config spec for a snapshot view must contain element * CHECKEDOUT as the first element rule.
If no version of an element matches any rule in the config spec:
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.
Each config spec rule must be contained within a single physical text line; you cannot use a backslash (UNIX and Linux), a caret (Windows), or any 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 path name in either single-quotes (‘) or double quotes (“).
In general, VOBs, views, and the ClearCase and ClearCase LT tools that access them are case-sensitive. Therefore, config spec rules must use case-correct path names.
You can use slashes (/) or backslashes (/) as path name separators in path name patterns and version selectors unless you are sharing the config spec between UNIX or Linux and Windows hosts. In that case, you must use slashes. (See Sharing config specs between UNIX or Linux and Windows hosts .)
Windows and UNIX or Linux 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 or Linux 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 and Linux. When the VOB tags diverge between regions, config spec element rules that use full path names (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 path names in element rules make sense. That is, a config spec with full path names 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:
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 path names 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, 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 or Linux network region, only Windows clients can compile the config spec.
When writing config specs to be shared by Windows and UNIX or Linux clients, use the slash (/), not the backslash (/), as the path name separator in path name patterns and version selectors. ClearCase and ClearCase LT on Windows can parse either separator in path names; ClearCase and ClearCase LT on UNIX and Linux recognize the slash only.
A standard version-selection rule takes this form:
The following subsections describe these components.
The scope specifies that the rule applies to all elements, or restricts the rule to a particular type of element.
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 is displayed in a view if both of these conditions are true:
A path name pattern, which can include any ClearCase or ClearCase LT wildcard (see the wildcards_ccase reference page for a complete list). For example:
Restrictions:
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: "..."
You can use a version label, version ID, or any other standard version selector. See the version_selector reference page for a complete list. Some examples follow:
Standard version selectors cannot select checked-out versions in a config spec rule. (They can in other contexts, such as the find command.) Instead, you must use the special version selector, CHECKEDOUT , described below.
The following special version selectors are valid only in a config spec rule, not in any other version-selection context:
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 path name as the element.
When you set or edit a config spec, the view_server resolves the do-pname with respect to the view's pre-existing 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.
Some config spec rules can include an additional clause, which modifies the rule's meaning.
date . time | date | time | now where:
date |
:= |
day-of-week | long-date |
time |
:= |
h [h ]: m [m ][: s [s ]] [UTC [ [ + | - ]h [h ][: m [m ] ] ] ] |
day-of-week |
:= |
today |yesterday |Sunday | ... |Saturday |Sun | ... |Sat |
long-date |
:= |
d [d ]– month [– [yy ]yy ] |
month |
:= |
January |... |December |Jan |... |Dec |
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 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 .)
Examples:
/main/LATEST –time 10–Jul.19:00 |
Most recent version on main branch, as of 7 P.M. on July 10. |
.../bugfix/LATEST –time yesterday |
Most recent version on a branch named bugfix (which can be at any branching level), as of the beginning of yesterday (12 A.M.). |
/main/bugfix/LATEST –time Wed.12:00 |
Most recent version on subbranch bugfix of the main branch, as of noon on the most recent Wednesday. |
–time 5–Dec.13:00 |
December 5, at 1 P.M. |
–time 11:23:00 |
Today, at 11:23 A.M. |
–time 12–jun–99 |
June 12, 1999, at 00:00 A.M. |
–time now |
Today, at this moment. |
–time 9-Aug.10:00UTC |
August 9, at 10 A.M. GMT. |
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 runtime. 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.
(This is a slight oversimplification. See the section 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.
Restriction: You cannot use –mkbranch in combination with –none or –error .
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:
1 |
element * CHECKEDOUT |
2 |
element * .../br2/LATEST |
3 |
element * .../br1/LATEST -mkbranch br2 |
4 |
element * MYLABEL -mkbranch br1 |
5 |
element * /main/LATEST |
1 |
element * CHECKEDOUT |
2 |
element * .../br2/LATEST |
3 |
element * .../br1/LATEST -mkbranch br2 |
4 |
element * MYLABEL -mkbranch br1 |
5 |
element * /main/LATEST |
If you check out an element in a view that currently selects the version labeled MYLABEL :
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.
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.
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 .
A time rule takes this form:
time date-time [ end time [ date-time ] ]
It is analogous to the –time clause. A time rule modifies the meaning of the special version label LATEST in subsequent rules, with the following exceptions:
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.
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.
Time rules may be nested. They may not include any query language constructs.
A file-inclusion rule takes this form:
include config-spec-pname
The argument specifies a text file that contains one or more config spec rules (possibly other include rules). Include files are re-read 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 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. Wildcarding is not supported; you must explicitly specify all elements to be loaded.
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.
In the context of loading a snapshot view, symbolic links can be characterized as VOB links, which point to objects inside the VOB, and non-VOB links, which point outside the VOB. Links are treated as follows:
UCM config specs are unlike config specs for base ClearCase and base ClearCase LT in that they are generated by mkstream and regenerated from time to time by chstream and rebase . You may edit UCM config specs only as follows:
Only custom rules that are correctly delimited are preserved when a UCM config spec is regenerated.
Add custom element-selection rules only between the custom element delimiters, as follows:
#UCMCustomElemBegin - DO NOT REMOVE - ADD CUSTOM ELEMENT RULES
AFTER THIS LINE rule
.
.
.
#UCMCustomElemEnd - DO NOT REMOVE - END CUSTOM ELEMENT RULES
The typical use for custom element selection is to add an include rule that enables the UCM view to see the contents of base ClearCase or base ClearCase LT VOBs. See File-inclusion rules .
Add custom load rules after the custom load delimiter, as follows:
#UCMCustomLoadBegin - DO NOT REMOVE - ADD CUSTOM LOAD RULES AFTER THIS LINE
rule
.
.
.
For more information, see Load rules .
include /proj/cspecs/v1_bugfix_rules
time 10-Jul.19:00
element /atria/lib/* .../new/LATEST
element * /main/LATEST
end time
element /usr/project/include/utility.h /main/3
element *.c /main/LATEST
element * .../bugfix/LATEST
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 |
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 |
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 |
element * CHECKEDOUT
element * .../bl3_bugs/LATEST
mkbranch bl3_bugs
element -file * BL2.6
element -file * /main/LATEST
end mkbranch bl3_bugs
element * REL3 –nocheckout
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".
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
element * CHECKEDOUT
element *... /main/LATEST
load /applets/cmdlg
load /applets/testdlg/opendlg.h
catcr , catcs , checkout , checkin , chstream , clearmake , cleartool , csh(1) , describe , edcs , find , ls , lsvtree , mkbranch , mkdir , mkelem , mklabel , mkstream , rebase , setcs , setview , startview , update , version_selector , wildcards_ccase , IBM Rational ClearCase Administrator's Guide