CVS check out i get four options. What do they mean? - branch

When I am checking out an application i get four options HEAD, Branches, Versions and Dates what do they mean? What is the difference between each of them?

A code repository is a tree of versions, each of which represents the state of the code at some particular point. It's possible to create a new branch of the tree from any point. Thus…
HEAD is the tip of the main trunk of the tree.
A branch is some other route through the tree of versions (e.g., to support a particular set of releases or develop a feature). If you ask to check out a branch, you typically get the tip of that branch.
A version represents an exact state of the code. In CVS, versions are per-file. (Other source control systems have global versioning.)
A date-based checkout represents getting the state of the code at a particular moment. This can be very useful for tracking down bugs.
The other thing that you'll see is a tagged version. That's where a name is given to a particular state of the tree (e.g., to represent an exact release).

Please take a look at Open Source Development with CVS, especially the Branches chapter. That explains how CVS works and what the head revision is and what branches are.

Related

What exactly does "Shelve base revisions of files under distributed version control systems" do in IntelliJ?

This is the official description of the docs
If this option is enabled, the base revision of files will be saved to
a shelf that will be used during a 3-way merge if applying a shelf
leads to conflicts. If it is disabled, IntelliJ IDEA will look for the
base revision in the project history, which may take a while;
moreover, the revision that the conflicting shelf was based on may be
missing (for example, if the history was changed as a result of the
rebase operation).
What does this setting do in more simple terms and does it have implications on merge conflicts as well without using shelves explicitly?
The reason for this question is mainly an issue we are frequently facing during merge conflicts, where old changes keep re-appearing out of nowhere that delete lines of code which are still being used.
One of the patch files in the .idea/shelf directory contains these exact changes which makes me assume it is related to what we are witnessing.
Uncommitted_changes_before_Checkout_at_28_12_2021_10_30_[Default_Changelist]

Intellij create scope from files differing in two branches

An Intellij Scope can be used to restrict the files analysed during "Inspect Code".
Question: Is there a way to define a scope from the files that differ between two commits or between a commit (or branch) and the current working directory?
This would simplify finding problems freshly introduced in a feature branch and would be particularly helpful for old code bases where running the inspections over the whole project generates too many unrelated findings.
Note that the Scope "uncommitted files" does not help a code review with several commits on a feature branch.
There is a feature request for it, please feel free to vote:
https://youtrack.jetbrains.com/issue/IDEA-145053/Run-inspections-for-the-scope-of-selected-commits

How to Group Plug-ins into Features

We are struggeling hard with how to use features the correct way.
Let’s say we have the plug-in org.acme.module which depends on org.thirdparty.specific and org.acme.core.
And we have the plug-in org.acme.other which depends on org.acme.core.
We want to create an application from these, which includes a target file and a product file. We have the following options:
One feature per module:
org.acme.core.feature
org.acme.core
org.acme.module.feature
org.acme.module
org.acme.other.feature
org.acme.other
org.thirdparty.specific.feature
org.thirdparty.specific
This makes the target and product files gigantic, and the dependencies are very hard to manage manually.
One feature per dependency group:
org.acme.module.feature
org.acme.core
org.acme.module
org.thirdparty.specific
org.acme.other.feature
org.acme.core
org.acme.other
This approach makes the dependencies very easy to manage, and the target and product files are easy to read and maintain. However it does not work at all. The moment org.acme.core changes, you need to change ALL the features. Furthermore, the application has no say in what to package, so it can’t even decide to update org.acme.core (because of a bugfix or something).
Platform Feature:
org.acme.platform.feature
org.acme.core
org.acme.other
org.thirdparty.specific (but could be its own feature)
org.acme.module.feature
org.acme.module
This is the approach used for Hello World applications and Eclipse add-ons - and it only works for those. Since all modules' target platforms would point to org.acme.platform.feature, every time anything changes for any platform plug-in, you'd have to update org.acme.platform.feature accordingly.
We actually tried that approach with only about 50 platform plug-ins. It's not feasible to have a developer change the feature for every bugfix. (And while Tycho supports version "0.0.0", Eclipse does not, so it's another bag of problems to use that. Also, we need reproducibility, so having PDE choose versions willy-nilly is out of the question.)
Again it all comes down to "I can't use org.acme.platform.feature and override org.acme.core's version for two weeks until the new feature gets released.
The entire problem is made even more difficult since sometimes more than one configuration of plug-ins are possible (let's say for different database providers), and then there are high level modules using other child modules to work correctly, which has to be managed somehow.
Is there something we are missing? How do other companies manage these problems?
The Eclipse guys seem to use the “one feature per module” approach. Not surprisingly, since it’s the only one that works. But they don’t use target platforms nor product files.
The key to a successful grouping is when to use "includes" in features and when to just use dependencies. The difference is that "includes" are really included, i.e. p2 will install included bundles and/or included features all the time. That's the reason why you need to update a bundle in every feature if it's included. If you don't update it, you will end up with multiple versions in the install.
Also, in the old day one had to specify dependencies in features. These days, p2 will mostly figure out dependencies from the bundles. Thus, I would actually stop specifying dependencies in features but just includes. Think of features as a way to specify what gets aggregated.
Another key point to grouping is - less is more. If you have as many features as bundles chances a pretty high that you have a granularity issue. Instead, think about what would a user install separately. There is no need to have four features for things that a user would never install alone. Features should not be understood as a way of grouping development/project structures - that's where folders in SCM or different SCM repos are ok. Think of features as deployment structures.
With that approach, I would recommend a structure similar to the following example.
my.product.base
base feature containing the bare minimum of the product
could be org.acme.core plus a few minimum
my.product.base.dependencies
features with 3rd party libraries for my.product.base
my.addon.xyz
feature bundling an add-on
separate features for things that can be installed separately
my.addon.xyz.dependencies
3rd party libraries for add-on dependencies
Now in the product definition I would list just my.product.base. There is no need to also list the dependencies features. p2 will fetch and install the dependencies automatically. However, if you want to bind your product to specific versions of the dependencies and don't want p2 to select any matching one, then you must include the my.product.base.dependencies feature.
In the target definition I would include a "my.product.sdk" feature. That feature is an aggregation feature of all other features. It makes target platform management easier. I typically create an sdk feature with everything.
Another feature that is also very often seen is a "master" feature. This is an "everything" feature that maybe used for creating a p2 repository during the build. The resulting p2 repository is then used for assembling products.
For a more real world example see here:
http://git.eclipse.org/c/gyrex/gyrex-server.git/tree/releng/features
Features and Continuous Delivery
There was a comment regarding frequent updates to feature.xml. A feature.xml only needs to be modified when there is a change in structure. No updates need to happen when the bundle version is modified. You should reference bundles in features with version 0.0.0. That makes Tycho to fill in the proper version at build time. Thus, all you need to do is commit a change to any bundle and then kick off a rebuild. Tycho also takes care of updating the feature qualifier based on the qualifiers of the contained bundles. Thus, the new feature qualifier will be different than in a previous build.

Does Ivy have different resolution behavior depending on status attribute?

My colleague pointed out a flaw in maintaining our artifacts (still somewhat new to Ivy):
The release builds are marked as “integration” which means it is rechecking for new versions on each build slowing down the build even when it has cached the dependencies.
That did not make much sense to me, since, I think, Ivy still needs to check what is in repo before making a decision about the version to deliver. So, I decided to research that a bit to understand exactly what are the effects of marking libraries with different status values.
I cannot find much in the documentation, though, or on the net. What am I missing?
Could someone please shed some light on this?
Thank you
The status is just a string, that can be defined for ivy. They don't affect the resolving of artifacts per se. It has no effect on the default retrieval. It's just a marker for an artifact.
Status:
Status of a revision A module's status indicates how stable a module
revision can be considered. It can be used to consolidate the status
of all the dependencies of a module, to prevent the use of an
integration revision of a dependency in the release of your module.
Three statuses are defined by default in Ivy:
integration: revisions builded by a continuous build, a nightly
build, and so on, fall in this category
milestone: revisions delivered to the public but not actually
finished fall in this category
release: a revision fully tested and labelled fall in this
category
You need to declare the dependency as changing or the resolver definition to achieve what your co-worker mentioned:
Changes in artifacts Some people, especially those coming from maven 2
land, like to use one special revision to handle often updated
modules. In maven 2 this is called a SNAPSHOT version, and some argue
that it helps save disk space to keep only one version for the high
number of intermediary builds you can make whilst developing.
Ivy supports this kind of approach with the notion of "changing
revision". A changing revision is just that: a revision for which Ivy
should consider that the artifacts may change over time. To handle
this, you can either specify a dependency as changing on the
dependency tag, or use the changingPattern and changingMatcher
attributes on your resolvers to indicate which revision or group of
revisions should be considered as changing.
Once Ivy knows that a revision is changing, it will follow this
principle to avoid checking your repository too often: if the module
metadata has not changed, it will considered the whole module
(including artifacts) as not changed. Even if the module descriptor
file has changed, it will check the publication data of the module to
see if this is a new publication of the same revision or not. Then if
the publication date has changed, it will check the artifacts' last
modified timestamps, and download them accordingly.
So if you want to use changing revisions, use the publish task to
publish your modules, it will take care of updating the publication
date, and everything will work fine. And remember to set
checkModified=true" on your resolver too!

Best approach to perform a CMMI Physical Configuration Audit?

The organization I currently work for an organization that is moving into the whole CMMI world of documenting everything. I was assigned (along with one other individual) the title of Configuration Manager. Congratulations to me right.
Part of the duties is to perform on a regular basis (they are still defining regular basis, it will either by quarterly or monthly) a physical configuration audit. This is basically a check of source code versions deployed in production to what we believe to be the source code versions in production.
Our project is a relatively small web application with written in Java. The file types we work with are java, jsp, xml, property files, and sql packages.
The problem I have (and have expressed but seem to be going ignored) is how am I supposed to physical log on to the production server and verify file versions and even if I could it would take a ridiculous amount of time?
The file versions are not even currently in the file(i.e. in a comment or something). It was suggested that we place visible version numbers on each screen that is visible to the users also. I thought this ridiculous also, since the screens themselves represent only a small fraction of the code we maintain.
The tools we currently use are Netbeans for our IDE and Serena Dimensions as our versioning tool.
I am specifically looking for ideas on how to perform this audit in a hopefully more automated way, that will be both accurate and not time consuming.
My idea is currently to add a comment to the top of each file that contains the version number of that file, a script that runs when a production build is created to create an XML file or something similar containing the file name and version file of each file in the build. Then when I need to do an audit I go to the production server grab the the xml file with the info, and compare it programmatically to what we believe to be in production, and output a report.
Any better ideas. I know this has to have been done already, and seems crazy to me that I have not found any other resources.
You could compute a SHA1 hash of the source files on the production server, and compare that hash value to the versions stored in source control. If you can find the same hash in source control, then you know what version is in production. If you can't find the same hash in source control, then there are untracked modifications in production and your new job title is justified. :)
The typical trap organizations fall into with the CMMI is trying to overdo everything. If I could suggest anything, it'd be start small & only do what you need. So consider any problems that you may have had in the CM area peviously.
The CMMI describes WHAT an organisation should do, but leaves the HOW up to you. The CMMI specification, chapter 2 is well worth a read - it describes the required, expected, and informative components of the specification - basically the goals are required, the practices are expected, and everything else is informative. This means there is only a small part of the specification which a CMMI appraiser can directly demand - the goals. At the practice level, it is permissable to have either the practices as described, or acceptable alternatives to them.
In the case of configuration audits, goal SG3 is "Integrity of baselines is established and maintained". SP3.2 says "Perform configuration audits to maintain integrity of the configuration baselines." There is nothing stated here about how often these are done, or how long they may take.
In my previous organisation, FCA/PCA was usually only done as part of the product release process, and we used ClearCase as the versioning tool, with labels applied across the codebase to define baselines. We didn't have version numbers in all the source files, nor did we have version numbers on all the products screens - the CM activity was doing the right thing & was backed up by audits, and this was never an issue in any CMMI appraisal.
We could use the deltas between labels to look at what files had changed, perform diffs to see the actual code changes. An important part of the process is being able to link those changes back to either a requirement/bug report/whatever the reason was which initiated the change.
Our auditing did use scripts to automate the process, but these were in-house developed scripts are specific to ClearCase - basically they would list all the files, their versions in the CM system, and the baseline/config item to which they belonged.
can't you use your source control for this? if you deploy a version and tag your sourcecontrol with that deployment, you can then verify against the source control system