(Base) ClearCase lock main branch for checkins - clearcase

I would like to lock the main branch of a component so that others can't check in any changes that break existing functionality or API compatibility. I've done a cleartool lock <element>##/main for all files in the component, but this also prevents checkout operations.
I've argued that checking out in a branch is still allowed, but I work in an environment with pretty primitive SCM practices, where an unnatural fear of branching exists. Is it possible to just lock the branch for checkins and still allow checkouts?
The only thing I can think about is setting a ClearCase trigger. Are there any better options out there?

As discussed in this thread, locking folders and elements is not ideal.
In order to enforce a policy without having to deploy it for every client, setting a trigger remains the best option.
That thread suggests (for checkout, but the same idea can apply to checkin)
place a trigger on the directory to stop the checkout.
By default when you place an "element" trigger on a directory it is applied to it's current elements and future directory elements via its attachment list and inheritance list.
cleartool mktrtype -ele -preop checkout -exec /path/to/script NO_CHECKOUT
cleartool mktrigger NO_CHECKOUT /path/to/dir_name
In your case, the /path/to/script (a path that should be accessible by all clients) needs to check if the current branch is /main (using the trigger environment variables, like CLEARCASE_BRTYPE).

Related

Clearcase equivalent to hg shelve

Is there a ClearCase equivalent to hg shelve (or git stash for those of the other persuasion)? The closest I can think of is doing uncheckouts and saving keep files, but that means I'd have to hunt down the keep files afterwards, re-checkout the files and merge. I realize that ClearCase and Mercurial/Git have different philosophies behind them, but I'd be interested if there is any work in making ClearCase more "usable".
I listed a few for other version control tools, but none for ClearCase.
I explained, for ClearCase UCM, that a shelve command isn't easy to implement.
Instead of just saving the .keep files, you could save patches (unix diff between a .keep and its original version), since a patch can be re-applied later.
The other approach is to modify the config spec (easier when in a non-UCM view) in order to checking the currently modified versions in a new branch (see this config spec)
You can then decide to merge that branch later.
The philosophy is quite different.
In Clearcase, if you need to work on another branch/release, you usually have to use another Clearcase view. If you have Clearcase/UCM, it is even more true as you would use another view attached to another UCM stream. You would not be able to use the same view, whereas in Git, you would be able to stick to the same clone and perform a git stash, git checkout in order to start working on another release.
Now let's assume you need to work on another feature, for the same release. Under Clearcase/UCM, you would be able to create a new activity (cleartool mkact) and work on this new activity, using the same view. All the changes made will then be associated with this new activity. You will also be able to switch back to the previous activity using the command cleartool setact. The tricky part is if you need to deliver the activities separately. This will not necessarily possible as you might need to deliver both at the same time depending on the content of the changeset. This doc about determining dependent UCM activities is quite useful. If you need to move some changeset between activities, you can use the command cleartool chactivity with -fcset and -tcset options.
As a summary, with Clearcase UCM, if it is for different release, switch views and streams. If it is for the same release, play around with the UCM activities, knowing that it is less flexible than git stash.

Clearcase equivalent of git no fast forward merge

What is the Clearcase equivalent of git's no fast forward (--no-ff) switch? Or how can I achieve the same functionality?
BACKGROUND
The situation is we are running multiple release branches and we need to be able to pull a feature or defect fix from the release branch if required. Currently (and I'm not the one managing Clearcase) all defect work is checked directly into the release branch, so backing out changes is time-consuming and potentially error-prone.
When using git with --no-ff, I can back out a feature or defect very quickly with minimal chance of causing an issue.
In ClearCase, you would instead cancel an activity (if you are using ClearCase UCM), or cancelling merges for a set of files with negative merges.
But there is no notion of "fast-forward": there is no HEAD to move, only versions (file by file) to merge. So if you know the merged versions, you can create new versions which cancel them (that is what the negative merge does).
There is no ff but there is also no HEAD in clearcase in the sense of git. The workflow is different. You always check in your code to a new checkin (or commit in git terminology). So it is like you are always doing a merge commit

Changing event record information in Clearcase

At our work, we are forced to use Clearcase UCM as our central repository (specifically for labelling/baselining, builds and code reviews), but our team wants to use Git as our real SCM system.
What we want to achieve is essentially a scraping service that takes the commits as they are pushed to our central Git repo, and push them on to a Clearcase VOB that is read-only as far as the development team is concerned, including important information such as the comment and the user name (exact date/time matching is not important, but getting the user correct is).
Our centralized Git server has been configured (using the excellent scm-manager) to accept Windows domain users and passwords, and our Clearcase servers use Windows domain accounts, but I am unsure how a scraper service would "impersonate" the correct user so this information is duplicated correctly in Clearcase.
I thought the chevent command might hold some promise, but that only gives access to the comment.
Is there any way to amend the details of a Clearcase event record once it is in the database, in particular the user-name? Or is there a better way to do this?
Again, we don't need a bi-directional bridge - all access to the Clearcase VOB as far as code commits is concerned would be through the scraper.
ClearCase is a file-by-file SCM, not a revision-based SCM.
(See "What are the basic ClearCase concepts every developer should know?" for a more detailed comparison between ClearCase and git)
That means, for each git commit, you need to:
clearfsimport into ClearCase any file included in the git commit.
Create a specific UCM activty for that import.
As a ClearCase admin, cleartool protect -chown on the activity: see "Why is the owner of the clearcase activity 'nobody'" (as well as a protect -chgrp, if the CLEARCASE_PRIMARY_GROUP environment variable wasn't correctly set at the time of the import).
Note that cleartool protect affects the entire "element" (file or directory), not just one version, so you cannot record the user id that way: the next import would overwrite that id with the id of the new committer whom content is imported.
Plus, you cannot changed the initial creator (see "Changing the name of the original creator of an element")
That means you should record that information (author and creator git id) in attribute:
see cleartool mkattr.
If I did want to accurately reflect the Git user as the "creator" of the new version of the file does that mean I would need a way to run clearfsimport as that user - impersonate them?
Yes: for each commit, you would need to clearfsimport "as" (runas in Windows, as mentioned in this thread) that use, in order for ClearCase to properly set the creator (if this is a new element) or the version author (if this is an update of an existing version).
The reason I didn't mention that possibility in the first place is that I don't have access to the credentials of another user, for me to switch to for each clearfsimport.
Other import tools (CVS, PCVS, RCS, SCCS, SSafe) simply:
ignore that creator/author information entirely.
add attributes of their own for tool-specific information (like the promotion group 'PVCS_GROUP', or RCS_REVISION.
Each time, you will find the limitation similar to:
clearexport_sccs ignores information in SCCS files that is not related to version-tree structure; this includes flags, ID keywords, user lists, and Modification Request numbers
most of our other systems that need the Clearcase history use the creator to reflect who made that change
That means your other systems can rely on the user ID version, except if it is the one used for the import (in which case they would consult the special attribute recording that data from the import)

Reverting a users changes in ClearCase

We use ClearCase as control version system.
In our system sometimes we make releases without some developers commits because of time limit.
For example I made some changes in six classes but another user did changes in all or some of them also. And I have to commit code without his changes. So I scan my files with previous versions so that I can revert his changes. But it's a slow and boring process.
Is there another way to do that? Maybe an extension or a script?
The only way to automate that process is through:
subtractive merge or negative merge (as described in this IBM article):
cleartool merge -to filename -delete -ver \main\branch\version_number
cset.pl, which can take all the checkins of an UCM activity and cancel them.
See "Clearcase: how to rollback all changes on specific branch?".
But this is for UCM (which might not be your case)
In both cases, the idea is to create a new version which cancels the version of your other developer.

Why dependency is triggered even if an activity is made as an obsolete?

In UCM project we are trying to deliver activity to default stream.
It is displaying that activity is having dependency with another activity.
As the dependent activity has no useful info we obsoleted it. But still it doesn't allow us to proceed and it force us to deliver that ?
Why dependency is being triggered even if the activity is obsolete?
The activity will be associated with your deliver (without choice) if:
there is a common file with other activities (file dependency)
you previously did a deliver to another stream (in which case it automatically link all the remaining activities together)
If the activity is small enough, the best course of action remains to deliver everything, and to cancel what you don't need.
If there is really no common file, one option mentioned in this old 2003 thread would be to try and change the owner (only by a ClearCase admin) of the activity.
See cleartool project:
cleartool protect -chown aNewOwner activity:anActivity#\aPvob
(you might have to "cleartool unlock activity:anActivity#\aPvob" first if it was "lock -obsolete")
#Samselvaprabu I have seen this happen before, this smells of hyperlinks. Can not be 100% sure if your problem is exactly same, but they have worked for me in the past:
checkvob -ucm activity:#\PVOB
which might point you to a bad hyperlink
checkvob -fix
Use ucmutil to do a similar job
Please be careful, there are always risks associated with messing with hyperlinks, so read the manuals and/or technotes before you actually run a checkvob -fix or something intrusive.

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