Next: , Up: The Usual Suspects


The Working Copy Administrative Area

You've already seen the basics of working copy structure in An Overview of CVS; in this section, we'll go into a bit more detail. Most of the details concern the files in the CVS/ administrative subdirectories. You already know about Entries, Root, and Repository, but the CVS/ subdirectory can also contain other files, depending on the circumstances. I'll describe those other files here, partly so they don't surprise you when you encounter them, and partly so you can fix them if they ever cause trouble.

CVS/Entries.Log

Sometimes, a file named CVS/Entries.Log will mysteriously appear. The sole purpose of this file is to temporarily cache minor changes to CVS/Entries, until some operation significant enough to be worth rewriting the entire Entries file comes along. CVS has no ability to edit the Entries file in place; it must read the entire file in and write it back out to make any change. To avoid this effort, CVS sometimes records small changes in Entries.Log, until the next time it needs to rewrite Entries.

The format of Entries.Log is like Entries, except for an extra letter at the beginning of each line. A means that the line is to be added to the main Entries file, and R means it is to be removed.

For the most part, you can ignore Entries.Log; it's rare that a human has to understand the information it contains. However, if you're reading over an Entries file to debug some problem in a working copy, you should also examine Entries.Log.

CVS/Entries.Backup

The CVS/Entries.Backup file is where CVS actually writes out a new Entries file, before renaming it to Entries (similar to the way it writes to temporary RCS files in the repository and then moves them to their proper name when they're complete). Because it becomes Entries when it's complete, you'll rarely see an Entries.Backup file; if you do see one, it probably means CVS got interrupted in the middle of some operation.

CVS/Entries.Static

If the CVS/Entries.Static file exists, it means that the entire directory has not been fetched from the repository. (When CVS knows a working directory is in an incomplete state, it will not bring additional files into that directory.)

The Entries.Static file is present during checkouts and updates and removed immediately when the operation is complete. If you see Entries.Static, it means that CVS was interrupted, and its presence prevents CVS from creating any new files in the working copy. (Often, running cvs update -d solves the problem and removes Entries.Static.)

The absence of Entries.Static does not necessarily imply that the working copy contains all of the project's files. Whenever a new directory is created in the project's repository, and someone updates their working copy without passing the -d flag to update, the new directory will not be created in the working copy. Locally, CVS is unaware that there is a new directory in the repository, so it goes ahead and removes the Entries.Static file when the update is complete, even though the new directory is not present in the working copy.

CVS/Tag

If the CVS/Tag file is present, it names a tag associated, in some sense, with the directory. I say "in some sense" because, as you know, CVS does not actually keep any revision history for directories and, strictly speaking, cannot attach tags to them. Tags are attached to regular files only or, more accurately, to particular revisions in regular files.

However, if every file in a directory is on a particular tag, CVS likes to think of the entire directory as being on the tag, too. For example, if you were to check out a working copy on a particular branch:

     floss$ cvs co -r Bugfix_Branch_1

and then add a file inside it, you'd want the new file's initial revision to be on that branch, too. For similar reasons, CVS also needs to know if the directory has a nonbranch sticky tag or date set on it.

Tag files contain one line. The first character on the line is a single-letter code telling what kind of tag it is, and the rest of the line is the tag's name. Currently, CVS uses only these three single-letter codes:

(If you see some other single-letter code, it just means that CVS has added a new tag type since this chapter was written.)

You should not remove the Tag file manually; instead, use cvs update -A.

Rarities

There are a few other files you may occasionally find in a CVS/ subdirectory:

These files are usually not the cause of problems, so I'm just listing them (see CVS Reference for their full descriptions).

Portability And Future Extension

As features are added to CVS, new files (not listed here) may appear in working copy administrative areas. As new files are added, they'll probably be documented in the Cederqvist manual, in the node Working Directory Storage. You can also start looking in src/cvs.h in the source distribution, if you prefer to learn from code.

Finally, note that all CVS/* files – present and future – use whatever line-ending convention is appropriate for the working copy's local system (for example, LF for Unix or CRLF for Windows). This means that if you transport a working copy from one kind of machine to the other, CVS won't be able to handle it (but then, you'd have other problems, because the revision-controlled files themselves would have the wrong line-end conventions for their new location).

Karl Fogel wrote this book. Buy a printed copy via his homepage at red-bean.com

copyright  ©  May 24 2019 sean dreilinger url: https://durak.org/sean/pubs/software/cvsbook/The-Working-Copy-Administrative-Area.html