Fossil  Check-Out Workflows

Because Fossil separates the concept of “check-out directory” from “repository DB file,” it gives you the freedom to choose from several working styles. Contrast Git, where the two concepts are normally intermingled in a single working directory, which strongly encourages the “update in place” working style.

Multiple-Checkout Workflow

With Fossil, it is routine to have multiple check-outs from the same repository:

    fossil clone /path/to/repo.fossil

    mkdir -p ~/src/my-project/trunk
    cd ~/src/my-project/trunk
    fossil open /path/to/repo.fossil    # implicitly opens “trunk”

    mkdir ../release
    cd ../release
    fossil open /path/to/repo.fossil release

    mkdir ../my-other-branch
    cd ../my-other-branch
    fossil open /path/to/repo.fossil my-other-branch

    mkdir ../scratch
    cd ../scratch
    fossil open /path/to/repo.fossil abcd1234

    mkdir ../test
    cd ../test
    fossil open /path/to/repo.fossil 2019-04-01

Now you have five separate check-out directories: one each for:

  • trunk
  • the latest tagged public release
  • an alternate branch you’re working on
  • a “scratch” directory for experiments you don’t want to do in the other check-out directories; and
  • a “test” directory where you’re currently running a long-running test to evaluate a user bug report against the version as of last April Fool’s Day.

Each check-out operates independently of the others.

This multiple-checkouts working style is especially useful when Fossil stores source code in programming languages where there is a “build” step that transforms source files into files you actually run or distribute. Contrast a switch-in-place workflow, where you have to rebuild all outputs from the source files that differ between those versions whenever you switch versions. In the above model, you switch versions with a “cd” command instead, so that you only have to rebuild outputs from files you yourself change.

This style is also useful when a check-out directory may be tied up with some long-running process, as with the “test” example above, where you might need to run an hours-long brute-force replication script to tickle a Heisenbug, forcing it to show itself. While that runs, you can open a new terminal tab, “cd ../trunk”, and get back to work.

Single-Checkout Workflows

Nevertheless, it is possible to work in a more typical Git sort of style, switching between versions in a single check-out directory.

The Idiomatic Fossil Way

The most idiomatic way is as follows:

    fossil clone /path/to/repo.fossil
    mkdir work-dir
    cd work-dir
    fossil open /path/to/repo.fossil on trunk...

    fossil update my-other-branch on your other branch in the same directory...

Basically, you replace the cd commands in the multiple checkouts workflow above with fossil up commands.

Opening a Repository by URI

In Fossil 2.12, we added a feature to simplify the single-worktree use case:

    mkdir work-dir
    cd work-dir
    fossil open

Now you have “trunk” open in work-dir, with the repo file stored as repo.fossil in that same directory.

Users of Git may be surprised that it doesn’t create a directory for you and that you cd into it before the clone-and-open step, not after. This is because we’re overloading the “open” command, which already had the behavior of opening into the current working directory. Changing it to behave like git clone would therefore make the behavior surprising to Fossil users. (See our discussions if you want the full details.)

Git-Like Clone-and-Open

In Fossil 2.14, we added a more Git-like alternative:

    fossil clone
    cd fossil

This results in a fossil.fossil repo DB file and a fossil/ working directory.

Note that our clone URI behavior does not commingle the repo and check-out, solving our major problem with the Git design.

If you want the repo to be named something else, adjust the URL:

    fossil clone

That gets you fsl.fossil checked out into fsl/.

For sites where the repo isn’t served from a subdirectory like this, you might need another form of the URL. For example, you might have your repo served from and want it cloned as my-project:

    fossil clone

The /repo addition is the key: whatever comes after is used as the repository name. See the docs for more details.