CHANGELOG.md

Airline - Change Log

3.x Deprecation

Future releases will start to focus on the 4.x builds which include some important new features e.g. first class positional argument support, better DI framework integration, that are not possible under 2.x/3.x without making breaking changes. You can see progress on 4.x by following the 4x branch and its CHANGELOG.md and Migrating.md files.

3.0.0

• Core Improvements
  • First class support for BigInteger and BigDecimal as numeric types
  • First class support for Path
  • Provided corrected spelling for ConvertResult.wasSuccessful(), old mis-spelt method preserved but marked as deprecated
  • Added a JpmsResourceLocator as an additional ResourceLocator to allow finding resources when running in a JPMS context (requires additional module airline-jpms-resources)
  • BREAKING - Only @AirlineModule is used as a composition annotation by default, use of the older @javax.inject.Inject or @jakarta.inject.Inject annotations MUST now be explicitly configured.
• Help Improvements
  • Added an @SeeAlso annotation to Airline Core (#51)
  • BREAKING - airline-help-bash has moved @BashCompletion annotation into com.github.rvesse.airline.annotations.help.bash to avoid package collisions between this module and the core in order to allow this module to become a JPMS module
• Fluent API Improvements
  • A ParserBuilder created by calling withParser() on a CliBuilder can now return control back to its parent via the parent() method for cleaner Fluid CLI definitions
• Dependency Updates
  • BREAKING - Minimum JDK Version is now 11
  • Apache Commons Collections upgraded to 4.4
  • Apache Commons Lang upgraded to 3.14.0
  • jakarta.inject and airline-backcompat-javaxinject were made optional so will no longer be pulled in automatically
  • Various build plugins updated to the latest available versions (this only impacts developers building the library from source)
  • Added new airline-help-external module with a dependency on Apache Commons CSV 1.10.0
  • Added new airline-jpms-resources module with a dependency on ClassGraph to enable resource location when Airline is used on Module Path i.e. JPMS runtime context
• Maven Plugin improvements
  • Some logging has moved up to INFO from DEBUG, so you no longer have to use -X to see it
• New airline-prompts module provides a Fluent API for defining user prompts (#92)
  • Prompt timeouts so non-interactive apps don't hang forever
  • Configurable prompt sources
  • Configurable prompt formatting
  • Prompt for keys, strings, passwords, options (from a pre-configured list) or a strongly typed value
  • Integrates with Airline's type conversion
• New airline-help-external modules provides new help annotations that allow more complex help to be provided via classpath/file resources rather than directly in the annotations. This is a generalisation of the mechanism already used by @Version annotation. (#52)
  • Adds @ExternalDiscussion @ExternalProse, @ExternalExitCodes, @ExternalExamples and @ExternalExamplesTabular annotations
• Build and Release Improvements
  • All Airline modules are now fully fledged JPMS modules meaning they can be used on the JVM Module Path instead of the Classpath where preferred
    • See airline-examples module for examples of constructing a module-info.java that pulls in other Airline modules and see modularExample script for examples of invoking an Airline based app using the Module Path

2.x Deprecation

3.0.0 is now released, so Airline 2.x will no longer be supported.

2.9.0

• Build Improvements
  • Added GitHub Actions based CI/CD for the repository
  • Added a new airline-backcompat-javaxinject module to aid Annotation Improvements (see below), this is included in the dependencies of the core airline module by default. Note that future 3.x releases may make this dependency optional as the Java ecosystem transitions away from using the old javax packages.
• Annotation Improvements
  • Added @AirlineModule as future replacement for existing usage of @Inject
  • @Inject can now be either javax.inject.Inject or jakarta.inject.Inject, and mixtures thereof are supported. This enables broader compatibility with applications that need/want to use either variant of the standard Java @Inject dependency.
• Parser Improvements
  • Choice of composition annotations is now configurable. Defaulting to supporting the new @AirlineModule annotation, and for backwards compatibility both variants of the @Inject annotation as noted above.
    • Use compositionAnnotationClasses field with the @Parser annotation
    • Use withCompositionAnnotations() or withDefaultCompositionAnnotations() with the ParserBuilder

NB: The changes to injection annotations have been carefully done to be fully backwards compatible with existing Airline annotations for the 2.9.x releases. Future minor and major releases will change the default behaviour to only support @AirlineModule. Therefore, you may wish to start migrating your applications to using this annotation sooner rather than later and explicitly exclude legacy dependencies. See the Migration Guide for more details on this.

2.8.5

• Restriction Improvements
  • New @RequiredUnlessEnvironment restriction for making an option/argument required only if one/more environment variables are not set
• Stopped generating the airline-offline-site artifact as it is superflous

2.8.4

• Restriction Improvements
  • New @NoOptionLikeValues restriction for explicitly rejecting values that look like options i.e. start with - or -- but didn't match a defined option e.g. user typos (#112)

2.8.3

• Parser Improvements
  • Added a GreedyMaybeListValueOptionParser to cover more cases where greedy parsing behaviour is desired (#110)

2.8.2

• Bug Fixes
  • Fix for some option parsers being overly greedy for arity=1 options and incorrectly consuming subsequent options (#110)
    • For most users the change should have no impact other than more reliable error reporting. For users who rely heavily upon ClassicGetOptParser you may notice the removal of this greediness. If you wish to retain the old behaviour configure your option parsers to include the new GreedyClassicGetOptParser.

2.8.1

• Bug Fixes
  • Fix for using Airline in JPMS environments (#102) (thanks to @jfallows)

2.8.0

• Core Improvements
  • @Option annotation now allows an array of values for the title field allowing options with arity > 1 to have distinct titles shown for each value the option accepts

2.7.2

• Bug Fixes
  • @AllowedEnumValues incorrectly provides help hint that values are case insensitive when they are actually case sensitive (#100)
  • @AllowedRawValues does not handle case insensitive mode correctly (#100)
  • @Option with type = OptionType.GLOBAL and type = OptionType.GROUP are not correctly parsed at the command level (#101)

2.7.1

• Bug Fixes
  • CollectAll handler collected multiple duplicates of the same error when certain restrictions were used. Now instead duplicates are combined into a single exception (#94)
  • CLIs could allow command classes with the same declared command name in their @Command annotation to silently override each other. Now instead an error will be thrown reporting the problem (#95)
  • When using group default commands and command abbreviation we can incorrectly ignore a value (#99)

2.7.0

• Bug Fixes
  • EnvVarLocator and JvmSystemPropertyLocator could resolve locations incorrectly if some placeholders were undefined
  • Fixes some corner cases with @FloatRange and @DoubleRange underlying implementation
  • Fix possible NPE in maven plugin (#45)
• Restriction Improvements
  • Added @File and @Directory as more explicit variants of @Path (#73)
  • Added @Negative and @Positive for numerics (#73)
  • Added @LengthRange and @ExactLength for strings (#73)
  • Added @AllowedEnumValues as a simpler way of specifying @AllowedRawValues on enum typed fields (#73)
  • Added @StartsWith and @EndsWith for enforcing prefixes/suffixes on strings (#73)
• Build Improvements
  • Provide module-info.java available so modules can be used on Module Path (#92) - Thanks to jfallows

2.6.0

• Core Improvements
  • Allow creating a Cli instance with an explicit ParserMetadata for situations where parser configuration cannot be specified via annotation e.g. using dynamically determined paths for user aliases
  • Abstract direct usage of System.out via Channels factory interface to allow the library to be used in environments that are not consoles (#78) - Thanks to sdorra
• Parser Improvements
  • Allow ./ as a user alias search location resolved as the current working directory
  • Allow extending how user alias search locations are resolved to support custom behaviours via new ResourceLocator interface
  • Add ability to specify a force prefix for aliases which allows alias definitions to override built-ins while still being able to invoke those built-ins (#72)
  • Add ability to specify default values for positional parameters in alias definitions (#69)
• Help Improvements
  • Remove deprecated methods from CommandUsageGenerator interface and add new usage() overload for more easily generating usage for single commands
• Annotation Improvements
  • Allow specifying global restriction annotations directly on classes used with SingleCommand
  • @Unrestricted can now be applied directly to classes to specify no global restrictions on single commands and CLIs
  • @Version can now use ResourceLocator to modify search locations
  • Help Sections annotations can now be placed onto @Cli annotated classes and will be inherited by all commands defined for the CLI. Commands can still override help sections as desired. (#59)
    • CLI defined help sections are included by CLI help generators (#57)
• Build Improvements
  • Now possible to build with JDK 9 and JDK 10. Note that we still compile for JDK 7 compatibility
  • Dependencies
    • Upgraded Apache Commons Lang to 3.7 (#82)
    • Upgraded Apache Commons Collections to 4.2 (#82)

2.5.0

• NEW - Added airline-maven-plugin that provides two goals (#45)
  • A generate goal for generating help for your commands and CLIs during a Maven build
  • A validate goal for validating that your @Command and @Cli annotated classes have valid annotations that Airline can generate a CLI from

2.4.1

• Parser Changes
  • ListValuesOptionParser now accepts any number of values that are a multiple of the arity of the option so can now be used for options that wish to allow multiple values in a single list
• Documentation Improvements
  • Documentation website now located in docs/ subfolder of master branch (#35)
  • New airline-docs-VERSION-offline-site.zip and .tar.gz artifacts contain a static build of the documentation website for offline reference (#70)
• Core Improvements
  • Removed some unnecessary helper methods from AirlineUtils in favour of JDK built-ins (#64)
• Help Improvements
  • Fixed some issues with UsagePrinter not correctly respecting configured column limits in some cases

2.4.0

• Bug Fixes
  • Fix bug in @MutuallyExclusiveWith error message (#66) - Thanks to GTarkin for reporting
  • Fix bug with flagNegationPrefix specified via annotation - Thanks to rkhaja for the fix
  • Add missing Javadoc

2.3.0

• Parsing Changes
  • New ParserErrorHandler interface for handling non-fatal parser errors (#53)
    • FailFast - Classic behaviour, throw as soon as error encountered
    • FailAll - Collect and aggregate non-fatal errors and throw as single error
    • CollectAll - Collect all non-fatal errors
    • New ParseResult<T> interface for representing parsing result and accessing success status and errors (if any)
    • Support for customising type converter on a per-option/arguments basis (#54)
• Help Changes
  • Added showHelpIfErrors() method to HelpOption for use with error handlers which collect errors e.g. CollectAll (#53)
• Annotation Changes
  • New errorHandler field on @Parser annotation for specifying error handler, defaults to FailFast for backwards compatible behaviour (#53)
  • New flagNegationPrefix field on @Parser to allow specifying that if a flag option (zero arity option) name starts with that prefix the value should be set to false as opposed to setting flags to true as is the normal behaviour (#63)
  • New description field on @Pattern to provide human readable explanation of regular expression restriction intent (#48)
  • Noted in Javadoc that @Version supports both properties and Manifest files as data sources (#56)
  • Use new typeConverterProvider field on @Option/@Arguments to customise the type converter for a field (#54)
    • Variety of built in converters provided for supporting more complex number formats
      • Alternative Bases: Hexadecimal, Octal and Binary
      • Abbreviations: KiloAs1000, KiloAs1024

2.2.0

• Bug Fixes
  • Fixed a possible infinite loop in parsing when a group contains both sub-groups and commands (#55)
  • Fixed possible non-deterministic ordering of option and arguments help hints (#50)
• Annotation Changes
  • Removed deprecated arity from @Arguments, the @MaxOccurrences restriction annotation (and its related annotations) provide for much finer grained control than this property did
  • Global restrictions can now be specified via annotations
• Help Changes
  • Removed the deprecated RONN help generators (use airline-help-man or airline-help-markdown instead)
    • This removes the airline-help-ronn module (Breaking)
  • New @Version annotation for embedding version information into generated help where the version information is pulled from properties files in your JARs or on the local file system
  • Multi-page help generators can now be configured with a base directory to control where the per-command files are created
• Restriction Changes
  • New GlobalRestrictionsFactory interface and corresponding registry in RestrictionsRegistry
    • Uses ServiceLoader for automatic discovery, provide a META-INF/services/com.github.rvesse.airline.restrictions.factories.GlobalRestrictionFactory file to specify global restriction factories
  • Global restrictions can now be specified by adding annotations to @Cli annotated classes
  • Improved OptionRestriction and ArgumentsRestriction interfaces
    • Old postValidate() method becomes finalValidate()
    • Revised postValidate() method with better type signature that takes the converted value
  • Support partial restrictions i.e. restrictions only apply to some of the values for @Option or @Arguments fields
    • Specified via @Partial/@Partials annotations in addition
• Parser Changes
  • Improve how restrictions for options and arguments are enforced
  • Options must always receive precisely their arity in values or a ParseOptionMissingValueException is thrown (at least with the built-in parsers)

2.1.1

• Bug Fixes
  • ManCommandUsageGenerator could incorrectly indent the arguments portion of the options list if both visible and hidden options are present
  • Man help output could fail in the options section if there were no visible options but some hidden options present
• Annotation Changes
  • Marked defunct fields of @Arguments annotation as deprecated
  • Marked various annotations as @Documented so they are included in JavaDoc output
  • All fields of @Alias annotation are now required
• Parser Changes
  • Made internal helper class ConvertResult public to make it easier to extend the DefaultTypeConverter
• Documentation Improvements
  • New website in progress at http://rvesse.github.io/airline/

2.1.0

• Module Additions and Changes
  • New airline-help-man module
    • ManSections moved into this module (Breaking)
  • RONN help generators moved to airline-help-ronn module (Breaking)
    • All RONN generators are marked as @deprecated since they are superseded by the Man and Markdown format generators
  • HTML help generators moved to airline-help-html module (Breaking)
  • Bash help generators moved to airline-help-bash module (Breaking)
    • CompletionBehaviour moved into this module (Breaking)
  • New airline-help-markdown module for generating Markdown help
• Help Improvements
  • New direct man page generation via ManCommandUsageGenerator, ManGlobalUsageGenerator and ManMultiPageGlobalUsageGenerator provided in the airline-help-man
    • These are intended to replace use of the existing RONN generators for generating Man pages
  • New direct Markdown generation via MarkdownCommandUsageGenerator, MarkdownGlobalUsageGenerator and MarkdownMultiPageGlobalUsageGenerator
    • These are intended to replace use of the existing RONN generators for generating Markdown help
  • CommandUsageGenerator has new overloads that take a ParserMetadata<T> object, old overloads are deprecated in favour of these. This allows generators to produce more accurate help in some circumstances.
  • Switched to using ServiceLoader to discover available help section factories avoiding the need to explicitly register these with HelpSectionRegistry
    • Provide a META-INF/services/com.github.rvesse.airline.help.sections.factories.HelpSectionFactory file to specify help section factories
    • HelpSectionRegistry moved to package com.github.rvesse.airline.help.sections.factories (Breaking)
    • HelpSectionFactory now required to implement a supportedAnnotations() method to declare the annotations it can turn into HelpSection instances (Breaking)
  • New @Copyright and @License annotations for adding copyright and license statements to help
  • New @ProseSection annotation for adding a custom prose section to help
  • Improved presentation of help hint for options/arguments annotated with @Port
  • Improved presentation of help hints for numeric ranges, they no longer show min/max if those are set to the min/max of their respective numeric types and the range is inclusive
  • Improved presentation of help hint for single value ranges
• Metadata Changes
  • User alias configuration are now preserved on a UserAliasesSource<T> class which is accessible via ParserMetadata<T>.getUserAliasesSource()
  • completionBehaviour and completionCommand are no longer fields on the @Option and @Arguments annotation. Instead use the @BashCompletion annotation from the airline-help-bash module
• Restriction Improvements
  • New @Path restriction for specifying that an arguments value is a path to a file/directory and applying restrictions on the path/file that should be enforced e.g. must exist, readable etc.
  • New @MutuallyExclusiveWith restriction for specifying that only one of some set of options may be specified but that those options are optional, this is thus a less restrictive version of @RequireOnlyOne
  • Switched to using ServiceLoader to discover available restriction factories avoiding the need to explicitly register these with the RestrictionRegistry
    • Factories are now required to implement a method indicating what annotations they can translate into restrictions (Breaking)
    • Provide a META-INF/services/com.github.rvesse.airline.restrictions.factories.OptionRestrictionFactory file to specify option restriction factories
    • Provide a META-INF/services/com.github.rvesse.airline.restrictions.factories.ArgumentsRestrictionFactory file to specify argument restriction factories
• Bug Fixes
  • @Port restriction would incorrectly reject valid values when applies to @Arguments annotated fields
  • Restrictions could report incorrect argument title when applied to arguments with multiple titles

2.0.1

• Bug Fixes
  • Fix @MinLength being an exclusive restriction i.e. value had to be greater than given length when intention was that value should be at least the given length
• Documentation
  • Add missing Javadocs to new annotations

2.0.0

2.0.0 represents substantial breaking changes over 1.x which were made to make the library more configurable and extensible. We strongly recommend reading the included Migrating.md for notes on how to migrate existing Airline powered CLIs forward.

• Dependency Changes
  • Removed Guava
  • Added Apache Commons Collections 4
• Builder improvements
  • All parser related options on CliBuilder are now moved to ParserBuilder which is access by calling .withParser() on the CliBuilder instance
  • Groups now support sub-groups and GroupBuilder provides withSubGroup() and getSubGroup() for working with these
• Annotation Changes
  • Various fields were removed from existing annotations in favour of moving them to separate annotations
    • @Command removes examples, discussion, exitCodes and exitCodeDescriptions
    • @Option removes required, allowedValues and ignoreCase
    • @Group can now be used to create sub-groups by inserting spaces into group names e.g. @Group(name = "foo bar") creates a group foo with a sub-group bar and applies any other configuration given to the sub-group
    • New @Cli annotation can be used to define a CLI entirely declaratively
    • New @Parser annotation can be used to customise parser for CLIs created with SingleCommand or as a field on a @Cli annotation
    • @Arguments removes required
  • New annotations for adding extended help to commands
    • @Discussion to add discussion, this replaces the discussion field of the @Command annotation
    • @Examples to add examples, this replaces the examples field of the `@Command annotation
    • @ExitCodes to add exit codes, this replaces the exitCodes and exitCodeDescriptions fields of the
    • Custom extended help sections can be created and registered such that they are automatically discovered by Airline
  • New restriction annotations for expressing restrictions on options and arguments
    • @Required to indicate required options/arguments, this replaces the required field on the @Option and @Arguments annotations
    • New @RequiredOnlyIf for conditionally requiring an option if another option is present
    • New @RequireSome for requiring at least one from some set of options
    • New @RequireOnlyOne for requiring exactly one from some set of options
    • @AllowedRawValues for limiting the raw string values an option can receive, this replaces the allowedValues and ignoreCase fields on the @Option annotation
    • New @AllowedValues for limiting the converted values an option can receive
    • New @MaxLength and @MinLength for limiting the length of the raw string values an option can receive
    • New @MinOccurrences, @MaxOccurrences and @Once for limiting how many times an option can appear
    • New @LongRange, @IntegerRange, @ShortRange, @ByteRange, @DoubleRange, @FloatRange and @LexicalRange for indicating that arguments once converted to the appropriate value type must fall within a given range
    • New @Port for restricting options to some port range(s)
    • New @NotEmpty and @NotBlank for requiring the raw string values be non-empty or non-blank (not all whitespace)
    • New @Pattern for requiring that the raw string values conform to some regular expression
    • New @Unrestricted to indicate that restrictions inherited from an overridden option should be removed
    • Custom restrictions can be created and registered such that they are automatically enforced by Airline
• Parser Improvements
  • TypeConverter is now an interface and configurable i.e. allows you to control how Airline turns raw string values into Java objects
  • Option parsing styles are now fully configurable (default behaviour remains as 1.x which uses the first 3 styles):
    • Classic GNU Get Opt Style
    • Long GNU Get Opt Style
    • Standard whitespace separated style
    • List value style i.e. --name a,b,c for higher arity options
    • Pair value style i.e. --name a=b for arity 2 options
    • Users can define and register their own custom option parsers as desired
  • Alias Improvements
    • Can now support optional alias chaining i.e. aliases can reference other aliases
• Metadata Improvements
  • Parsing specific metadata moved to ParserMetadata class which is accessible via GlobalMetadata.getParserConfiguration()
  • GlobalMetadata is now a generic class taking the command type as the type parameter
• Help Improvements
  • New HelpHint interface which is used by restrictions to provide help
  • New HelpSection interface for adding custom help sections to commands
  • More advanced and flexible formatting of extra help hints and sections in all existing generators
  • Help supports providing help for sub-groups, help for groups will include information about available sub-groups

1.0.2

• Various minor improvements from Christian Raedel
  • Long style option parser --name=value now also accepts colon separated values e.g. --name:value
  • allowedValues on @Option can now be set to use case insensitive comparison
  • TrueColor can be instantiated from a hex value

1.0.1

• Fix regression in RonnCommandUsageGenerator

1.0.0

• Code Structure Refactoring
  • Root package is now com.github.rvesse.airline
  • Main library now lives under lib/ in source control
  • New examples module under examples/ in source control
• Annotation Improvements
  • @Group can now be marked as hidden
  • discussion parameter of @Command is now a String[] rather than a single string making it easier to specify long descriptions
• CLI Improvements
  • User defined command aliases are now supported
  • CLI builder classes are now public and have their own builder package
  • Parser Improvements
    • All parser errors in the parser package have public constructors
• Help Improvements
  • Help generators can now optionally display hidden commands and options
  • Help.help() static improved:
    • Respects command abbreviation when enabled
    • Additional overloads for enabled output of hidden commands and options
  • Bash completion fixes and improvements:
    • Default command and default group command completion now included
    • Functions for default group commands (i.e. top level commands) are no longer missing if there are also groups present
  • Fixed a bug with hidden options not displaying in synopsis even when including hidden options was enabled
  • HelpOption improved:
    • Generated help will include program and group name where applicable
    • It can now be used to show help with an arbitrary usage generator
    • showHelpIfRequested() guarantees to only display help once
    • showHelp() can be used to display help regardless
  • Command usage generators now print each item in the discussion as a separate paragraph
• IO Improvements
  • New com.github.rvesse.airline.io package with useful helper stuff for doing advanced console IO
  • Support for colorised output streams and writers:
    • Basic ANSI Colors (8 Colors, normal and bright variants)
    • 256 Colors (Basic ANSI Colors plus 3 colour palettes plus grayscale palette) - See color chart for more detail
    • True Color (24 bit colour i.e. 16 million colours) - Many terminals may not support this mode
    • Includes basic text decorations e.g. bold, underline

0.9.2

• Annotation Improvements
  • Arguments improvements
    • An arity can now be specified to set the maximum arity for arguments and throws a ParseTooManyArgumentsException if too many arguments are seen
  • New DefaultOption annotation
    • Allows a field already annotated with @Option to also be marked as the default option under certain circumstances. This allows one option to be specified arguments style i.e. the -n or --name can be omitted provided only one field is annotated this way, it has an arity of 1 and no fields are annotated with @Arguments
• Bash Completion Fixes
  • Bash Completion Scripts for CLI that use groups are now valid Bash and function correctly
  • Generated scripts use more unique function names to avoid clashes between different airline generated completion scripts
• CLI Improvements
  • CLIs can now have command abbreviation enabled which allows users to only type part of the command name provided that the portion typed is unambiguous
  • CLIs can now have option abbreviation enabled which allows users to only type part of the option name provided that the portion typed is unambiguous
• Package Refactoring
  • Parser functionality moved into io.airlift.airline.parser package

0.9.1

• Help improvements
  • Refactored various usage generators to make them easier to extend

0.9

• Annotation improvements
  • Command improvements
    • Added exitCodes and exitDescriptions for declaring the exit codes a command can produce and their meanings
• Help improvements
  • All command help generator now include exit code information if declared for a command via the exitCodes and exitDescriptions properties
  • Add new RonnMultiPageGlobalUsageGenerator which generates a top level overview RONN page and then individual RONN files for each sub-command
  • Fix broken sort order of commands and groups in various help generator implementations
  • Add documentation of allowedValues to all help generators
  • Fix typo in presentation of -- option in various help generators
  • Fix presentation of examples to avoid need for users to use markup in their annotations

0.8

• Forked from upstream repository
  • Group ID changed to com.github.rvesse
  • Currently package names remain same as upstream (bar the help system) to make it easy to migrate existing apps to this fork.
  • Please note that future releases will change the package names to align with the Group ID.
• Annotation improvements
  • Option improvements:
    • allowedValues properties is actually enforced and produces ParseOptionIllegalValueException if an invalid value is received
    • New override and sealed properties allowing derived commands to change some properties of the annotation
    • Overridden options may change the type when it is a narrowing conversion
    • New completionBehaviour and completionCommand properties allowing defining behaviours for the purposes of completion script generators
  • Arguments improvements
    • New completionBehaviour and completionCommand properties allowing defining behaviours for the purposes of completion script generators
  • Group annotation for specifying groups
  • Command annotation supports discussion and examples
• Help system improvements
  • Most portions moved to io.airlift.airline.help package
  • Help printing respects new lines allowing them to be used in longer descriptions
  • Support for additional examples and discussion sections in command help
  • Abstracted out help generation into interfaces with multiple concrete implementations:
    • Command Line (the existing help system)
    • Ronn
    • HTML
    • Bash auto-completion script
• Support for Command Factories