Class: SasLinter::Rules::FormatForUnknownVariable

Inherits:
SasLinter::Rule show all
Defined in:
lib/sas_linter/rules/format_for_unknown_variable.rb

Overview

Flag ‘format` / `informat` / `attrib … format=` statements that name a variable referenced nowhere else in the file. Almost always a typo (`attrib totalscore format=flagx.;` when every other use is `total_score`). SAS itself silently binds the format to a phantom column and runs; downstream tooling that resolves variable references (e.g. sas-ruby) refuses to compile such a file.

The rule is conservative: a file that pulls variables in from an external source — ‘set`, `merge`, `update`, `infile`, `input` — is skipped entirely, since a format target may legitimately name a column the linter can’t see.

Constant Summary collapse

TT = 
SasLexer::Lexer::TokenType
FORMAT_KIND_BY_TYPE = 
{
  TT::KW_FORMAT => :format,
  TT::KW_INFORMAT => :informat,
  TT::KW_ATTRIB => :attrib
}.freeze
EXTERNAL_INPUT_TYPES = 
[
  TT::KW_SET, TT::KW_MERGE, TT::KW_UPDATE, TT::KW_INFILE, TT::KW_INPUT
].freeze
DECLARATION_TYPES =

Statements that name variables for declaration only — the names they reference don’t count as “real uses” because if a variable only appears in declaration statements it’s still dead code. Keyword-typed openers:

[
  TT::KW_FORMAT, TT::KW_INFORMAT, TT::KW_ATTRIB,
  TT::KW_LABEL, TT::KW_LENGTH, TT::KW_KEEP, TT::KW_DROP, TT::KW_ARRAY
].freeze
DECLARATION_TEXT =

IDENTIFIER-typed openers (the lexer doesn’t keyword these):

`retain` is a data-step declaration;
`value` / `invalue` / `picture` introduce a `proc format` body.

%w[retain value invalue picture].freeze

Instance Attribute Summary

Attributes inherited from SasLinter::Rule

#autofix

Instance Method Summary collapse

Methods inherited from SasLinter::Rule

all, #autofix?, description, fetch, from_config, inherited, #initialize, register, registry, rule_id, severity, supports_autofix?

Constructor Details

This class inherits a constructor from SasLinter::Rule

Instance Method Details

#check(tokens, path:, all_tokens: nil, source: nil) ⇒ Object

rubocop:disable Lint/UnusedMethodArgument



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# File 'lib/sas_linter/rules/format_for_unknown_variable.rb', line 52

def check(tokens, path:, all_tokens: nil, source: nil) # rubocop:disable Lint/UnusedMethodArgument
  external_input = false
  targets = []
  use_names = Set.new

  each_statement(tokens) do |stmt|
    opener = stmt[0]

    if EXTERNAL_INPUT_TYPES.include?(opener[:type])
      external_input = true
      next
    end

    kind = FORMAT_KIND_BY_TYPE[opener[:type]]
    if kind
      collect_targets(stmt, kind, targets)
      next
    end

    next if declaration_statement?(opener)

    collect_uses(stmt, use_names)
  end

  return [] if external_input

  targets.filter_map do |t, kind|
    next if use_names.include?(t[:text].downcase)

    finding(
      line: t[:start_line],
      column: t[:start_column] + 1,
      message: "`#{kind}` assigns a format to `#{t[:text]}` but " \
               "that variable is not referenced anywhere else in " \
               "this file — likely a typo.",
      path: path
    )
  end
end