Linters & Formatters

phpcs scans PHP files against a coding standard and reports violations without changing anything; phpcbf reads the same ruleset and rewrites files, fixing only the violations whose sniffs implement an automatic fix and leaving the rest for a human.

PHPStan's rule levels are a cumulative strictness dial from 0 (unknown classes, functions, wrong argument counts) to 10 (errors even for implicit mixed); each level adds checks to all lower ones, and max is an alias for the highest.

A .rubocop.yml keys each cop by qualified name, such as Layout/LineLength: Enabled: false switches it off, keys like Max tune it, and Exclude skips paths. A department (Lint, Style, Layout, Metrics...) groups cops and can be configured as one.

Standard Ruby is a gem that runs RuboCop with a fixed, non-configurable ruleset. Run standardrb (or rake standard after requiring standard/rake), add --fix for safe corrections; it ignores .rubocop.yml and reads only options from .standard.yml.

detekt's complexity set measures branching and size: CyclomaticComplexMethod and CognitiveComplexMethod per function, LongMethod and LargeClass in lines, NestedBlockDepth, ComplexCondition, LongParameterList, TooManyFunctions. Defaults sit near 60 lines per function and 600 per class.

The committed .php-cs-fixer.dist.php is a PHP file that returns a PhpCsFixer\Config whose Finder selects the files and whose setRules() array enables rule sets like @PER-CS or @PHP8x5Migration plus individual rules, which can be tuned or switched off.

A phpcs.xml.dist ruleset pulls in a whole standard, a category, one sniff or one message with rule ref, removes parts of it with exclude, and tunes a sniff's public settings with properties, so the whole team runs the same checks.

vendor/bin/phpstan analyse --generate-baseline writes phpstan-baseline.neon, an ignoreErrors list with message, identifier, count and path per file, which you include in phpstan.neon; fixed errors leave entries unmatched, PHPStan reports them, and you regenerate to shrink it.

Under parameters, level sets the rule level, paths lists what to analyse and excludePaths removes fnmatch patterns; includes pulls in other config files. A --level or paths given on the command line replace the config values rather than merging with them.

rubocop -a applies only corrections RuboCop marks safe; rubocop -A also applies unsafe ones that may change behaviour. A correction counts as safe only when the cop has both Safe and SafeAutoCorrect true, which is the default.

A # rubocop:disable Cop comment at the end of a line silences that line; on its own line it silences until # rubocop:enable Cop. rubocop:todo is an alias marking a suppression to revisit. -- reason documents why.

Publish the shared file in a gem and load it with inherit_gem, or point inherit_from at a path or URL. inherit_gem files load first, then inherit_from files in list order (last wins), and the repository's own settings override both.

Annotate the smallest declaration that contains the finding with Kotlin's @Suppress, passing detekt's rule id — for example @Suppress("MagicNumber") on one function. detekt reuses the standard annotation; a configured alias or the rule set id also works.

Annotate the code with Kotlin's @Suppress using the fully qualified rule id, for example @Suppress("ktlint:standard:function-naming") on the declaration, or @file:Suppress(...) at the top of the file. The old ktlint-disable comments were removed in ktlint 1.0.

Native array only says the value is an array. list<T> means keys 0, 1, 2 with no gaps and values of type T; array{id: int, name?: string} describes each key and its type, optional keys included.

Pass a comma-separated list: rubocop --only Layout/LineLength,Style/StringLiterals runs just those, --only Lint a department, and --except Metrics runs everything else. Add -a to autocorrect only that selection.

Not every ktlint rule can autocorrect. Rules that need a human decision, such as naming rules and max-line-length, only report; the format task rewrites what it can and leaves those violations in place, so the check task still fails on them.

phpcs:ignore suppresses one line, phpcs:disable suppresses everything until phpcs:enable or the end of the file, and phpcs:ignoreFile skips the file; naming a sniff code limits the suppression so other violations still surface.

Each PHP_CodeSniffer message is an error or a warning with a severity, 5 by default; phpcs shows it only if that severity reaches the threshold, 5 by default, and every shown message, warnings included, makes the exit code non-zero.

Narrow it: after if (class_exists($name)) PHPStan treats $name as class-string, and the check also protects runtime. An inline @var is trusted without proof, so the docs call it a last resort and prefer fixing the type at its source.

Put // @phpstan-ignore argument.type (reason) on or above the line, naming the error identifier; it silences only that error there. ignoreErrors in phpstan.neon matches by message regex or rawMessage, identifier, path and count across files.

PHPStan stores the last result and a file dependency tree in %tmpDir%/resultCache.php and re-analyses only changed files and files that reference their symbols; setting tmpDir inside the workspace lets CI save and restore that cache between runs.

Array settings such as Exclude replace the inherited array, so a one-entry AllCops Exclude drops the default vendor/**/* pattern. inherit_mode: merge: [Exclude] unions the lists instead, globally or for one cop.

TargetRubyVersion tells RuboCop the oldest Ruby the code must run on; it selects the parser grammar and which version-gated cops apply. Unset, RuboCop reads the gemspec, .ruby-version, mise.toml, .tool-versions or Gemfile.lock, else assumes 2.7.

standardrb --fix applies only corrections RuboCop marks safe; --fix-unsafely also applies unsafe ones that can change behaviour. fix: true in .standard.yml makes fixing the default, and --no-fix turns it off for one run.

standardrb --generate-todo writes .standard_todo.yml, mapping each file that has offenses to the cops it violates; Standard then ignores those, warns about them, and still checks everything else. # standard:disable Cop comments silence specific lines like RuboCop's own directives.

ignore skips paths, or only named cops for a path; default_ignores (true by default) adds Standard's own skips such as vendor/**/, bin/ and db/schema.rb. ruby_version sets RuboCop's target; without it Standard uses the Ruby running standardrb.

First ask whether the findings are real. If the rule is right but over-broad, narrow it with its own options or an excludes path glob; move the number only if the codebase's idiom genuinely differs; set active: false only when the rule contradicts a deliberate convention.

A custom sniff is a class implementing PHP_CodeSniffer\Sniffs\Sniff inside a standard's Sniffs/Category folder: register() returns the token types it listens for, and process() inspects each matching token and reports violations through the File object.