Motivation

Rewrite forge-fmt entirely to use Solar as the Solidity/Yul parser and AST, and using a structured pretty-printing algorithm.

The language-agnostic implementation of the pretty-printer (src/pp) is based on rustc_ast_pretty and prettyplease, both MIT and Apache licensed. See prettyplease's README for algorithm notes.

The goal of this PR is to make progress with #9317, and fixing existing issues with the formatter while trying to maintain compatibility as much as possible.

This PR will not be replacing the formatter yet, opting to create a separate crate crates/fmt-2 to reduce unrelated changes and aid with review. A follow-up PR will replace crates/fmt and deal with fallout in-tree.

Issues

Issues that will be fixed with the new implementation. Not closed by this PR, but by the follow-up that will hook the new implementation up; see paragraph above.

• Fixes\ feat(fmt): allow line_length to be a hard requirement #4450
• Fixes\ Extend capabilities of Foundry formatter to be compatible with Solidity's official style guide #6147
• Fixes\ feat(forge fmt): sorting of imports adds newlines in groups #7944
• Fixes\ bug(forge fmt): ignores forgefmt: disable-next-line in argument lists #8557
• Fixes\ feat(fmt): support transient keyword by moving to Solar #9088
• Fixes\ Forge fmt does not work with custom storage layouts 0.8.29 #10244
• Fixes\ bug(fmt): modifies argument list in the presence of forgefmt: disable-next-line #11249
• Fixes\ forge fmt: some syntax in custom storage layout causes ParserError #11096
• Fixes\ Formatter behavior for numbers fractional part #11474

Tests state

• ArrayExpressions
• BlockComments
• BlockCommentsFunction
• ConditionalOperatorExpression
• ConstructorDefinition
• ConstructorModifierStyle
• ContractDefinition
• DocComments
• DoWhileStatement
• EmitStatement
• EnumDefinition
• EnumVariants
• ErrorDefinition
• EventDefinition
• ForStatement
• FunctionCall
• FunctionCallArgsStatement
• FunctionDefinition
• FunctionDefinitionWithFunctionReturns
• FunctionType
• HexUnderscore
• IfStatement
• IfStatement2
• ImportDirective
• InlineDisable
• IntTypes
• LiteralExpression
• MappingType
• ModifierDefinition
• NamedFunctionCallExpression
• NumberLiteralUnderscore
• OperatorExpressions
• PragmaDirective
• Repros
• ReturnStatement
• RevertNamedArgsStatement
• RevertStatement
• SimpleComments
• SortedImports
• StatementBlock
• StructDefinition
• ThisExpression
• TrailingComma
  • NOTE: solar error
• TryStatement
• TypeDefinition
• UnitExpression
• UsingDirective
• VariableAssignment
• VariableDefinition
• WhileStatement
• Yul
  • STYLE: pending review
• YulStrings

Supported Configs:

• indent_style = IndentStyle
• multiline_func_header: MultilineFuncHeaderStyle
• line_length: usize
• tab_width: usize
• bracket_spacing: bool
• int_types: IntTypes
• quote_style: QuoteStyle
• number_underscore: NumberUnderscore
• hex_underscore: HexUnderscore
• single_line_statement_blocks: SingleLineBlockStyle
• override_spacing: bool
• wrap_comments: bool
• ignore: Vec<String>
• contract_new_lines: bool
• sort_imports: bool
• pow_no_space: bool feat(fmt): option to remove spaces between number and exponent #4512

Pending TODOs

• update README