active-compat-level (AJSON)

Synopsis: dh_assistant active-compat-level

Outputs information about which compat level the package is using.

For packages without valid debhelper compatibility information (whether missing, ambiguous, not supported or simply invalid), this command operates on a "best effort" basis and may abort when error instead of providing data.

The returned JSON dictionary contains the following key-value pairs:

active-compat-level

The compat level that debhelper will be using. This is the same as DH_COMPAT when present or else declared-compat-level. This can be null when no compat level can be detected.

declared-compat-level

The compat level that the package declared as its default compat level. This can be null if the package does not declare any compat level at all.

declared-compat-level-source

Defines how the compat level was declared. This is null (for the same reason as declared-compat-level) or one of:

supported-compat-levels (AJSON, CRFA)

Synopsis: dh_assistant supported-compat-levels

Outputs information about which compat levels, this build of debhelper knows about.

This command accepts no options or arguments.

which-build-system (AJSON)

Synopsis: dh_assistant which-build-system [build step] [build system options]

Output information about which build system would be used for a particular build step. The build step must be one of configure, build, test, install or clean and must be the first argument after which-build-system when provided. If omitted, it defaults to configure as it is the most reliable step to use auto-detection on in a clean source directory. Note that build steps do not always agree when using auto-detection - particularly if the configure step has not been run.

Additionally, the clean step can also provide "surprising" results for builds that rely on a separate build directory. In such cases, debhelper will return the first build system that uses a separate build directory rather than the one build system that configure would detect. This is generally a cosmetic issue as both build systems are all basically a glorified rm -fr builddir and more precise detection is functionally irrelevant as far as debhelper is concerned.

The option accepts all debhelper build system arguments - i.e., options you can pass to all of the dh_auto_* commands plus (for the install step) the --destdir option. These options affect the output and auto-detection in various ways. Passing -S or --buildsystem overrides the auto-detection (as it does for dh_auto_*) but it still provides introspection into the chosen build system.

Things that are useful to know about the output:

• The key build-system is the build system that would be used by debhelper for the given step (with the given options, debhelper compat level, environment variables and the given working directory). When -S and --buildsystem are omitted, this is the result of debhelper's auto-detection logic.

  The value is valid as a parameter for the --buildsystem option.

  The special value none is used to denote that no build system would be used. This value is not present in --list parameter for the dh_auto_* commands, but since debhelper/12.9 the value is accepted for the --buildsystem option.

  Note that auto-detection is subject to limitations in regards to third-party build systems. While debhelper does support auto-detecting some third-party build systems, they must be installed for the detection to work. If they are not installed, the detection logic silently skips that build system (often resulting in build-system being none in the output).

• The build-directory and buildpath values serve different but related purposes. The build-directory generally mirrors the --builddirectory option where as buildpath is the output directory that debhelper will use. Therefore the former will often be null when --builddirectory has not been passed while the latter will generally not be null (except when build-system is none).
• The dest-directory (--destdir) is undefined for all build steps except the install build step (will be output as null or absent). For the same reason, --destdir should only be passed for install build step.

  Note that if not specified, this value is currently null by default.

• The parallel value is subject to DEB_BUILD_OPTIONS. Notably, if that does not include the parallel keyword, then parallel field in the output will always be 1.
• Most fields in the output can be null. Particular if there is no build system is detected (or when --buildsystem=none). Additionally, many of the fields can be null even if there is a build system if the build system does not use/set/define that variable.

detect-hook-targets (AJSON)

Synopsis: dh_assistant detect-hook-targets

Detects possible override targets and hook targets that dh(1) might use (provided that the relevant command is in the sequence).

The detection is based on scanning the rules file for any target that might look like a hook target and can therefore list targets that are in fact not hook targets (or are but will never be triggered for other reasons).

The detection uses a similar logic for scanning the rules file and is therefore subject to makefile conditionals (i.e., the truth value of makefile conditionals can change whether a hook target is visible in the output of this command). In theory, you would have to setup up the environment to look like it would during a build for getting the most accurate output. Though, a lot of packages will not have conditional hook targets, so the "out of the box" behaviour will work well in most cases.

The output looks something like this:

    {
       "commands-not-in-path": [
          "dh_foo"
       ],
       "hook-targets": [
          {
             "command": "dh_strip_nondeterminism",
             "is-empty": true,
             "package-section-param": null,
             "filename": "debian/rules",
             "target-name": "override_dh_strip_nondeterminism"
          },
          {
             "command": "dh_foo",
             "is-empty": false,
             "package-section-param": "-a",
             "filename": "debian/rules",
             "target-name": "override_dh_foo-arch"
          }
       ]
    }

In more details:

commands-not-in-path

This attribute lists all the commands related to hook targets, which dh_assistant could not find in PATH. These are usually caused by either the command not being installed on the system where dh_assistant is run or by the command not existing at all.

If you are using this command to verify an hook target is present, please double check that the command is spelled correctly.

hook-targets

List over hook targets found along with additional information about them.

This command accepts no options or arguments.

detect-unknown-hook-targets (AJSON, LINT)

Synopsis: dh_assistant detect-unknown-hook-targets [--output-format=json] [command-options]

Detects unknown and possibly misspelled override targets and hook targets in debian/rules that will most likely not be used by dh(1).

This command differs from detect-hook-targets subtly in the scope. The detect-hook-targets will list all targets that looks like hook targets whether they are applicable or not. This command show all hook targets, for which a command cannot be found in any sequence. Accordingly, this command is better for linting purposes whereas detect-hook-targets is better if you want to know which hook targets are present. All the limitations listed in detect-hook-targets about scanning the rules file apply equally to this command.

This command will attempt will attempt to load any sequence add-on listed via build-dependencies and therefore these must be installed. Additional modules can be passed via --with like with dh(1) as needed.

This command will also need one of the following perl modules to be available: Text::Levenshtein, Text::LevenshteinXS, Text::Levenshtein::XS. The first one can be installed via apt install libtext-levenshtein-perl.

The text output is intended for human consumption and should be self-explanatory. Since it is not stable, it will not be documented. The JSON output looks something like this:

    {
       "unknown-hook-targets": [
          {
             "target-name": "execute_before_dh_instlal",
             "filename": "debian/rules",
             "candidates": [
                "execute_before_dh_install"
             ]
          }
       ]
    }

In more details:

unknown-hook-targets

List of all the unknown hook targets found along with additional information about them.

issues

If present, then it is a list of one or more reasons why this output is definitely incomplete. Each element in the list is an object with the following keys:

This command accepts the following options:

--output-format=FORMAT

Request a certain type of output format. Valid values are text or json.

The text format is intended for human consumption and may change between versions without any regard for machine consumption. If you want to use this command for machine consumption, please use the JSON format.

--no-linter-exit-code, --linter-exit-code

These options control whether the command should exit with the linter exit code (2) or not (0) when an unknown target is found. By default, it uses the linter exit code when an unknown target is found.

--with addon, --without addon

These options behave the same as the dh(1) options with the same name.

list-commands (RJSON)

Synopsis: dh_assistant list-commands [--output-format=json] [command-options]

Load all dh sequence add-ons and extract a full list of all commands that will be invoked across all sequences. The command makes no attempt to filter out commands that will not be run due to override targets or due to certain sequences not being run (by dh or at all).

As the command will attempt to load all plugins, they must be installed.

The text output is intended for human consumption and should be self-explanatory. Since it is not stable, it will not be documented. The JSON output looks something like this:

    {
       "commands": [
          {
             "command": "dh_auto_build"
          },
          {
             "command": "dh_auto_clean"
          },
          [... more commands listed here... ]
       ],
       "issues": [
            {
                "issue": "load-addon",
                "addon": "foo"
            }
       ]
    }

commands

The top level key containing the list of all commands. Each element in the list are an object and can have the following keys:

issues

If present, then it is a list of one or more reasons why this output is definitely incomplete. Each element in the list is an object with the following keys:

This command accepts the following options:

--output-format=FORMAT

Request a certain type of output format. Valid values are text or json.

The text format is intended for human consumption and may change between versions without any regard for machine consumption. If you want to use this command for machine consumption, please use the JSON format.

--with addon, --without addon

These options behave the same as the dh(1) options with the same name.

list-guessed-dh-config-files (AJSON)

Synopsis: dh_assistant list-guessed-dh-config-files [command-options]

Load all dh sequence add-ons, determine the full list of commands could be used by this source package and for each command used, then attempt to guess which "config files" these commands are interested in.

Note this command only guesses "per command config files". Standard global config files such as debian/control, debian/rules, and debian/compat are not included in this output.

As the command name implies, the resulting output is not a full list (and will never be). The dh_assistant tool have to derive this from optional metadata that commands can choose to provide and dh_assistant has no means to validate that this metadata is up to date.

As the command will attempt to load all plugins, they must be installed.

The text output is intended for human consumption and should be self-explanatory. Since it is not stable, it will not be documented. The JSON output looks something like this:

    {
       "config-files": [
          {
             "commands": [
                {
                   "command": "dh_autoreconf_clean"
                }
             ],
             "file-type": "pkgfile",
             "pkgfile": "autoreconf.before"
          },
          {
             "commands": [
                {
                   "command": "dh_installgsettings"
                }
             ],
             "file-type": "pkgfile",
             "pkgfile": "gsettings-override"
          },
          # [ ... more entries here ...]
       ],
       "issues": [
           {
                "issue": "load-addon",
                "addon": "foo"
           }
       ]
    }

config-files

The top level key containing the list of all config-files. Each element in the list are an object and can have the following keys:

issues

If present, then it is a list of one or more reasons why this output is definitely incomplete. Each element in the list is an object with the following keys:

This command accepts the following options:

--with addon, --without addon

These options behave the same as the dh(1) options with the same name.

log-installed-files (BLD)

Synopsis: dh_assistant log-installed-files -ppkg [--on-behalf-of-cmd=dh_foo] path ...

Mark one or more paths as installed for a given package. This is useful for telling dh_missing(1) that the paths have been installed manually.

The --on-behalf-of-cmd option can be used by third-party tools to have dh_assistant list them as the installer of the provided paths. The convention is to use the basename of the tool itself as its name (e.g. dh_install).

Please keep in mind that:

• No glob or substitution expansion is done by dh_assistant on the provided paths. If you want to use globs, have the shell perform the expansion first.
• Paths must be given as relative to the source root directory (e.g., debian/tmp/...)
• You can provide a directory. If you do, the directory and anything recursively below it will be considered as installed. Note that it is fine to provide the directory even if paths inside of it has been excluded as long as the directory is fully "covered".
• Do not worry about providing the same filename twice in different invocations to dh_assistant due to -arch / -indep overrides. While it will be recorded multiple internally, dh_missing(1) will deduplicate when it parses the records.

Note this command only marks paths as installed. It does not actually install them - the caller should ensure that the paths are in fact handled (or installed).

restore-file-on-clean (BLD)

Synopsis: dh_assistant restore-file-on-clean FILE ...

This command will take a backup of listed files and tell dh_clean(1) to restore them when it runs.

Note that generally you do not need to restore modified files on clean. Often you can get away with just removing them if they are regenerated anyway (which is the most common case for files being modified during builds). Use this command when something taints a file and the build does not cope with the file being removed.

The file is stored in debian/.debhelper. If you remove this directory manually without calling dh_clean(1) then your dh_assistant provided backup is gone permanently and the restore will never occur. At this point, only a version control system or another backup can restore the files.

The command has the following limitations:

No thread-safety - concurrency will corrupt the restore

The command relies on updating an internal index and concurrent writes will cause it to be corrupt.

While most dh_* commands does not use the underlying function, any of them could do so. Avoid running another dh_* command while dh_assistant processes this command (especially running multiple concurrent instances of dh_assistant restore-file-on-clean is asking for corruption!).

Files only, not directories nor symlinks to files

This command will only restore files; not directories or symlinks to files. It will reject any non-files.

Additionally, if the directory containing the file is removed, the restore will fail (as debhelper does not track the directory, it cannot restore it reliably). If this happens, you can do a mkdir to restore the directory and run dh_clean(1) again to get the files back. After that, consider what went wrong and whether you are using the correct tool(s).

Strict file names

All filenames must be relative to the package root (without using the ./ prefix). No hidden files (that is any file starting with a period .) and no version control directories (such as CVS). The checks are best effort.

These checks are here to ensure you do not accidentally trash important data that would help you undo mistakes.

Heavy duty

The command takes a full copy of all files you pass it. This is fine for a handful of small files, which is the intended use-case. If you find yourself passing 10+ files or very large files, you might be applying a sledgehammer where you needed a different tool.

supports (CFFA)

Synopsis: dh_assistant supports COMMAND

This command is a scripting aid to programmatically determine whether dh_assistant knows about a given subcommand. Pass the name of a subcommand and this command will exit successfully if the subcommand was known and unsuccessfully otherwise.