NAME

       Lintian::Tags - Manipulate and output Lintian tags

SYNOPSIS

           my $tags = Lintian::Tags->new;
           my $proc = Lintian::Processable::Package->new ('/path/to/file');
           $tags->file_start ($proc);
           $tags->file_overrides ('/path/to/an/overrides-file');
           $tags->tag ('lintian-tag', 'extra tag information');
           tag ('other-lintian-tag', 'with some extra data');
           tag ('third-lintian-tag'); # with no extra).
           my %overrides = $tags->overrides ($proc);
           my %stats = $tags->statistics;
           if ($tags->displayed ('lintian-tag')) {
               # do something if that tag would be displayed...
           }

DESCRIPTION

       This module stores metadata about Lintian tags, stores configuration about which tags
       should be displayed, handles displaying tags if appropriate, and stores cumulative
       statistics about what tags have been seen.  It also accepts override information and
       determines whether a tag has been overridden, keeping override statistics.  Finally, it
       supports answering metadata questions about Lintian tags, such as what references Lintian
       has for that tag.

       Each Lintian::Tags object has its own tag list, file list, and associated statistics.
       Separate Lintian::Tags objects can be maintained and used independently.  However, as a
       convenience for Lintian's most typical use case and for backward compatibility, the first
       created Lintian::Tags object is maintained as a global default.  The tag() method can be
       called as a global function instead of a method, in which case it will act on that global
       default Lintian::Tags object.

CLASS METHODS

       new()
           Creates a new Lintian::Tags object, initializes all of its internal statistics and
           configuration to the defaults, and returns the newly created object.

       tag(TAG, [EXTRA, ...])
           Issue the Lintian tag TAG, possibly suppressing it or not displaying it based on
           configuration.  EXTRA, if present, is additional information to display with the tag.
           It can be given as a list of strings, in which case they're joined by a single space
           before display.

           This method can be called either as a class method (which is exported by the
           Lintian::Tags module) or as an instance method.  If called as a class method, it uses
           the first-constructed Lintian::Tags object as its underlying object.

           This method throws an exception if it is called without file_start() being called
           first or if an attempt is made to issue an unknown tag.

INSTANCE METHODS

   Configuration
       display(OPERATION, RELATION, SEVERITY, CERTAINTY)
           Configure which tags are displayed by severity and certainty.  OPERATION is "+" to
           display the indicated tags, "-" to not display the indicated tags, or "=" to not
           display any tags except the indicated ones.  RELATION is one of "<", "<=", "=", ">=",
           or ">".  The OPERATION will be applied to all pairs of severity and certainty that
           match the given RELATION on the SEVERITY and CERTAINTY arguments.  If either of those
           arguments are undefined, the action applies to any value for that variable.  For
           example:

               $tags->display('=', '>=', 'important');

           turns off display of all tags and then enables display of any tag (with any certainty)
           of severity important or higher.

               $tags->display('+', '>', 'normal', 'possible');

           adds to the current configuration display of all tags with a severity higher than
           normal and a certainty higher than possible (so important/certain and
           serious/certain).

               $tags->display('-', '=', 'minor', 'possible');

           turns off display of tags of severity minor and certainty possible.

           This method throws an exception on errors, such as an unknown severity or certainty or
           an impossible constraint (like "> serious").

       show_experimental(BOOL)
           If BOOL is true, configure experimental tags to be shown.  If BOOL is false, configure
           experimental tags to not be shown.

       show_overrides(BOOL)
           If BOOL is true, configure overridden tags to be shown.  If BOOL is false, configure
           overridden tags to not be shown.

       sources([SOURCE [, ...]])
           Limits the displayed tags to only those from the listed sources.  One or more sources
           may be given.  If no sources are given, resets the Lintian::Tags object to display
           tags from any source.  Tag sources are the names of references from the Ref metadata
           for the tags.

       profile(PROFILE)
           Use the PROFILE (Lintian::Profile) to determine which tags are suppressed, the
           severity of the tags and which tags are non-overridable.

   File Metadata
       file_start(PROC)
           Adds a new file from a processable, initializes the data structures used for
           statistics and overrides, and makes it the default file for which tags will be issued.
           Also call Lintian::Output::print_end_pkg() to end the previous file, if any, and
           Lintian::Output::print_start_pkg() to start the new file.

           This method throws an exception if the file being added was already added earlier.

       file_overrides(OVERRIDE-FILE)
           Read OVERRIDE-FILE and add the overrides found there which match the metadata of the
           current file (package and type).  The overrides are added to the overrides hash in the
           info hash entry for the current file.

           file_start() must be called before this method.  This method throws an exception if
           there is no current file and calls fail() if the override file cannot be opened.

       load_overrides
           Loads overrides for the current file.  This is basically a short-hand for finding the
           overrides file in the lab and calling files_overrides on it if it is present.

       file_end()
           Ends processing of a file.

           This does two things.  First it emits "unused-override" tags for all unused overrides.
           Secondly, it calls Lintian::Output::print_end_pkg to mark the end of the package.

           Note that this method is called by file_start if it detects another entry is already
           active.

   Statistics
       overrides(PROC)
           Returns a reference to the overrides hash for the given processable.  The keys of this
           hash are the tags for which are overrides.  The value for each key is another hash,
           whose keys are the extra data matched by that override and whose values are the counts
           of tags that matched that override.  Overrides matching any tag by that name are
           stored with the empty string as metadata, so:

               my $overrides = $tags->overrides('/some/file');
               print "$overrides->{'some-tag'}{''}\n";

           will print out the number of tags that matched a general override for the tag some-
           tag, regardless of what extra data was associated with it.

       statistics([PROC])
           Returns a reference to the statistics hash for the given processable or, if PROC is
           omitted, a reference to the full statistics hash for all files.  In the latter case,
           the returned hash reference has as keys the file names and as values the per-file
           statistics.

           The per-file statistics has a set of hashes of keys to times seen in tags: tag names
           (the "tags" key), severities (the "severity" key), certainties (the "certainty" key),
           and tag codes (the "types" key).  It also has an "overrides" key which has as its
           value another hash with those same four keys, which keeps statistics on overridden
           tags (not included in the regular counts).

   Tag Reporting
       displayed(TAG)
           Returns true if the given tag would be displayed given the current configuration,
           false otherwise.  This does not check overrides, only whether the tag severity,
           certainty, and source warrants display given the configuration.

       suppressed(TAG)
           Returns true if the given tag would be suppressed given the current configuration,
           false otherwise.  This is different than displayed() in that a tag is only suppressed
           if Lintian treats the tag as if it's never been seen, doesn't update statistics, and
           doesn't change its exit status.  Tags are suppressed via profile().

       ignored_overrides()
           Returns a hash of tags, for which overrides have been ignored.  The keys are tag names
           and the value is the number of overrides that has been ignored.

AUTHOR

       Originally written by Russ Allbery <rra@debian.org> for Lintian.

SEE ALSO

       lintian(1), Lintian::Output(3), Lintian::Tag::Info(3)