(kdesrc-build-logging)=
# kdesrc-build's build logging

(logging-overview)=
## Logging overview

Logging is a kdesrc-build feature whereby the output from every command
that kdesrc-build runs is saved to a file for examination later, if
necessary. This is done because it is often necessary to have the output
of these programs when there is a build failure, because there are so
many reasons why a build can fail in the first place.

(log-directory-layout)=
### Logging directory layout

The logs are always stored under the log directory. The destination of
the log directory is controlled by the [log-dir](#conf-log-dir) option,
which defaults to `${source-dir}/log` (where `${source-dir}` is the
value of the [source-dir](#conf-source-dir) option. The in rest of this
section, this value will be referred to as `${log-dir}`).

Under `${log-dir}`, is a set of directories, one for every time that
kdesrc-build was run. Each directory is named with the date, and the run
number. For instance, the second time that kdesrc-build is run on May
26, 2004, it would create a directory called `2004-05-26-02`, where the
2004-05-26 is for the date, and the -02 is the run number.

For your convenience, kdesrc-build will also create a link to the logs
for your latest run, called `latest`. So the logs for the most recent
kdesrc-build run should always be under `${log-dir}/latest`.

Now, each directory for a kdesrc-build run will itself contain a set of
directories, one for every KDE module that kdesrc-build tries to build.
Also, a file called `build-status` will be contained in the directory,
which will allow you to determine which modules built and which failed.

```{note}
If a module itself has a submodule (such as extragear/multimedia,
playground/utils, or KDE/kdelibs), then there would actually be a
matching layout in the log directory. For example, the logs for
KDE/kdelibs after the last kdesrc-build run would be found in
`${log-dir}/latest/KDE/kdelibs`, and not under
`${log-dir}/latest/kdelibs`.
```

In each module log directory, you will find a set of files for each
operation that kdesrc-build performs. If kdesrc-build updates a module,
you may see filenames such as `git-checkout-update.log` (for a module
checkout or when updating a module that has already been checked out).
If the `configure` command was run, then you would expect to see a
`configure.log` in that directory.

If an error occurred, you should be able to see an explanation of why in
one of the files. To help you determine which file contains the error,
kdesrc-build will create a link from the file containing the error (such
as `build-1.log` to a file called `error.log`).

The upshot to all of this is that to see why a module failed to build
after your last kdesrc-build, the file you should look at first is
`${log-dir}/latest/module-name/error.log`.

```{tip}
If the file `error.log` is empty (especially after an installation),
then perhaps there was no error. Some of the tools used by the KDE build
system will sometimes mistakenly report an error when there was none.

Also, some commands will evade kdesrc-build's output redirection and
bypass the log file in certain circumstances (normally when performing
the first Git checkout), and the error output in that case is not in the
log file but is instead at the Konsole or terminal where you ran
kdesrc-build.
```