This command should be considered experimental because there's only
partial integration with the rest of SwiftLint's infrastructure, and the
command is very likely to change in the near future.
This can effectively replace the `unused_declaration` analyzer rule and
in fact re-uses the same rule identifier to simplify migrations.
However, instead of using SourceKit requests, this parses the index
store generated by the Swift compiler, in addition to SwiftSyntax, which
means it runs it can run in seconds instead of hours when analyzing
projects with tens of thousands of Swift files.
In addition to Swift, this also catches dead C, C++, Objective-C
declarations, mostly by accident. There's no way to disable the rule for
those files at the moment.
Over the years, SwiftLintFramework had become a fairly massive monolith,
containing over 400 source files with both core infrastructure and
rules.
Architecturally, the rules should rely on the core infrastructure but
not the other way around. There are two exceptions to this:
`custom_rules` and `superfluous_disable_command` which need special
integration with the linter infrastructure.
Now the time has come to formalize this architecture and one way to do
that is to move the core SwiftLint functionality out of
SwiftLintFramework and into a new SwiftLintCore module that the rules
can depend on.
Beyond enforcing architectural patterns, this also has the advantage of
speeding up incremental compilation by skipping rebuilding the core
functionality when iterating on rules.
Because the core functionality is always useful when building rules, I'm
opting to import SwiftLintCore in SwiftLintFramework as `@_exported` so
that it's implicitly available to all files in SwiftLintFramework
without needing to import it directly.
In a follow-up I'll also split the built-in rules and the extra rules
into their own modules. More modularization is possible from there, but
not planned.
The bulk of this PR just moves files from `Source/SwiftLintFramework/*`
to `Source/SwiftLintCore/*`. There are some other changes that can't be
split up into their own PRs:
* Change jazzy to document the SwiftLintCore module instead of
SwiftLintFramework.
* Change imports in unit tests to reflect where code was moved to.
* Update `sourcery` make rule to reflect where code was moved to.
* Create a new `coreRules` array and register those rules with the
registry. This allows the `custom_rules` and
`superfluous_disable_command` rule implementations to remain internal
to the SwiftLintCore module, preventing more implementation details
from leaking across architectural layers.
* Move `RuleRegistry.registerAllRulesOnce()` out of the type declaration
and up one level so it can access rules defined downstream from
SwiftLintCore.
JP Simard