Module: MilkTea::Linter::FixEngine

Defined in:
lib/milk_tea/tooling/linter/fix_engine.rb

Constant Summary collapse

BINARY_OP_CHARS = 
%w[+ - * / % & | ^ < > = ! ? :].freeze

Class Method Summary collapse

Class Method Details

.apply_fix_edits(lines, edits) ⇒ Object 



28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 28

def self.apply_fix_edits(lines, edits)
  edits.sort_by { |e| [-e.start_line, -e.start_char] }.each do |edit|
    if edit.start_line == edit.end_line
      line = lines[edit.start_line]
      next unless line

      lines[edit.start_line] = +"#{line[0...edit.start_char]}#{edit.new_text}#{line[edit.end_char..]}"
    else
      prefix = (l = lines[edit.start_line]) ? l[0...edit.start_char] : ""
      suffix = (l = lines[edit.end_line]) ? l[edit.end_char..] : ""
      lines[edit.start_line..edit.end_line] = ["#{prefix}#{edit.new_text}#{suffix}"]
    end
  end
  lines
end

.balanced_line?(text) ⇒ Boolean

Returns:

  • (Boolean) 


391
392
393
394
395
396
397
398
399
400
401
402
403
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 391

def self.balanced_line?(text)
  depth = 0
  text.each_char do |char|
    case char
    when "(", "["
      depth += 1
    when ")", "]"
      depth -= 1
      return false if depth.negative?
    end
  end
  depth.zero?
end

.edits_for_rule(code, lines, warning) ⇒ Object 



9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 9

def self.edits_for_rule(code, lines, warning)
  case code
  when "prefer-let"             then prefer_let_edits(lines, warning)
  when "redundant-ignored-match-binding" then redundant_ignored_match_binding_edits(lines, warning)
  when "prefer-let-else"        then prefer_let_else_edits(lines, warning)
  when "prefer-var-else"        then prefer_var_else_edits(lines, warning)
  when "redundant-bool-compare" then redundant_bool_compare_edits(lines, warning)
  when "redundant-cast"        then redundant_cast_edits(lines, warning)
  when "redundant-else"         then redundant_else_edits(lines, warning)
  when "redundant-return"       then redundant_return_edits(lines, warning)
  when "redundant-type-annotation" then redundant_type_annotation_edits(lines, warning)
  when "redundant-unsafe"       then redundant_unsafe_edits(lines, warning)
  when "prefer-inline-methods"  then prefer_inline_methods_edits(lines, warning)
  when "unused-import"          then unused_import_edits(lines, warning)
  when "trailing-list-comma"    then trailing_list_comma_edits(lines, warning)
  else []
  end
end

.edits_to_lsp_text_edits(edits, uri) ⇒ Object 



44
45
46
47
48
49
50
51
52
53
54
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 44

def self.edits_to_lsp_text_edits(edits, uri)
  edits.map do |edit|
    {
      range: {
        start: { line: edit.start_line, character: edit.start_char },
        end:   { line: edit.end_line,   character: edit.end_char },
      },
      newText: edit.new_text,
    }
  end
end

.inner_has_top_level_operators?(inner) ⇒ Boolean

Returns:

  • (Boolean) 


418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 418

def self.inner_has_top_level_operators?(inner)
  depth = 0
  i = 0
  while i < inner.length
    case inner[i]
    when "(", "[", "{"
      depth += 1
    when ")", "]", "}"
      depth -= 1 if depth > 0
    when *BINARY_OP_CHARS
      if depth == 0 && (inner[i] == "-" || inner[i] == "~") && start_of_expression?(inner, i)
        i += 1
        next
      end
      return true if depth == 0
    end
    i += 1
  end
  false
end

.match_paren(line, open_pos) ⇒ Object 



405
406
407
408
409
410
411
412
413
414
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 405

def self.match_paren(line, open_pos)
  depth = 0
  (open_pos...line.length).each do |i|
    case line[i]
    when "(" then depth += 1
    when ")" then depth -= 1; return i if depth == 0
    end
  end
  nil
end

.prefer_inline_methods_edits(lines, warning) ⇒ Object

Moves the methods of an extending X: block inline into the matching struct X: declaration. Only rewrites when the struct immediately precedes the extending block (blank lines allowed between them); other layouts are left alone since the move would be non-local.



161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 161

def self.prefer_inline_methods_edits(lines, warning)
  name = warning.symbol_name
  return [] unless name && warning.line

  struct_idx = lines.index { |l| l.match?(/\A\s*struct\s+#{Regexp.escape(name)}\b/) }
  return [] unless struct_idx

  last_member_idx = nil
  ((struct_idx + 1)...lines.length).each do |i|
    l = lines[i]
    break if !l.chomp.empty? && !l.start_with?(" ", "\t")

    last_member_idx = i unless l.chomp.empty?
  end
  return [] unless last_member_idx

  ext_start_idx = warning.line - 1
  return [] unless last_member_idx < ext_start_idx

  ext_end_idx = ext_start_idx
  ((ext_start_idx + 1)...lines.length).each do |i|
    l = lines[i]
    break if !l.chomp.empty? && !l.start_with?(" ", "\t")

    ext_end_idx = i unless l.chomp.empty?
  end

  method_lines = lines[(ext_start_idx + 1)..ext_end_idx].to_a
  method_lines.shift while method_lines.first && method_lines.first.chomp.empty?
  method_lines.pop while method_lines.last && method_lines.last.chomp.empty?
  return [] if method_lines.empty?

  between = lines[(last_member_idx + 1)...ext_start_idx]
  return [] unless between.all? { |l| l.chomp.empty? }

  method_text = method_lines.join
  new_text = "#{lines[last_member_idx].chomp}\n\n#{method_text}"

  [FixEdit.new(start_line: last_member_idx, start_char: 0, end_line: ext_end_idx + 1, end_char: 0, new_text: new_text)]
end

.prefer_let_edits(lines, warning) ⇒ Object

── per-rule edit generators ──────────────────────────────────────────



58
59
60
61
62
63
64
65
66
67
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 58

def self.prefer_let_edits(lines, warning)
  return [] unless warning.line

  line_idx = warning.line - 1
  original = lines[line_idx]
  return [] unless original&.match?(/\bvar\b/)

  new_line = original.sub(/\bvar\b/, "let")
  [FixEdit.new(start_line: line_idx, start_char: 0, end_line: line_idx + 1, end_char: 0, new_text: new_line)]
end

.prefer_let_else_edits(lines, warning) ⇒ Object 



82
83
84
85
86
87
88
89
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 82

def self.prefer_let_else_edits(lines, warning)
  return [] unless warning.line

  fix = Linter.build_prefer_let_else_fix(lines, warning.line - 1, symbol_name: warning.symbol_name)
  return [] unless fix

  [FixEdit.new(start_line: fix[:start_line_idx], start_char: 0, end_line: fix[:end_line_idx] + 1, end_char: 0, new_text: fix[:new_text])]
end

.prefer_var_else_edits(lines, warning) ⇒ Object 



91
92
93
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 91

def self.prefer_var_else_edits(lines, warning)
  prefer_let_else_edits(lines, warning)
end

.redundant_bool_compare_edits(lines, warning) ⇒ Object 



95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 95

def self.redundant_bool_compare_edits(lines, warning)
  return [] unless warning.line && warning.column && warning.length

  line_idx = warning.line - 1
  line = lines[line_idx]
  return [] unless line

  start_char = warning.column - 1
  end_char = start_char + warning.length
  return [] if start_char.negative? || end_char > line.length

  expr_text = line[start_char...end_char]
  replacement = Linter.redundant_bool_compare_replacement(expr_text)
  return [] unless replacement

  [FixEdit.new(start_line: line_idx, start_char:, end_line: line_idx, end_char:, new_text: replacement)]
end

.redundant_cast_edits(lines, warning) ⇒ Object 



247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 247

def self.redundant_cast_edits(lines, warning)
  return [] unless warning.line && warning.column

  line_idx = warning.line - 1
  line = lines[line_idx]
  return [] unless line

  start = warning.column - 1
  return [] unless start >= 0 && start < line.length

  arrow = line.index("<-", start)
  return [] unless arrow

  type_ref = line[start...arrow]
  return [] unless type_ref.match?(/\A[A-Za-z_][A-Za-z0-9_\[\]\.,\s@]*\z/)

  arrow_end = arrow + 2

  # When only the parentheses are redundant (the cast itself is still
  # needed), remove just the `(` and matching `)`.
  if warning.message&.include?("parentheses")
    return [] unless arrow_end < line.length && line[arrow_end] == "("

    open_paren = arrow_end
    close_paren = match_paren(line, open_paren)
    return [] unless close_paren

    return [FixEdit.new(start_line: line_idx, start_char: open_paren, end_line: line_idx, end_char: open_paren + 1, new_text: ""),
            FixEdit.new(start_line: line_idx, start_char: close_paren, end_line: line_idx, end_char: close_paren + 1, new_text: "")]
  end

  # Cast to same type / own->ptr / widening are redundant — remove the
  # `TargetType<-` prefix. When the inner expression is then left
  # parenthesized with no operators, also strip the orphaned parens.
  new_start = start

  # When the cast is inside an `unsafe:` expression, also remove the
  # `unsafe: ` wrapper.
  unsafe_keyword = line.rindex("unsafe:", new_start)
  if unsafe_keyword
    prefix = line[unsafe_keyword...new_start]
    if prefix.match?(/\Aunsafe:\s*\z/)
      new_start = unsafe_keyword
    end
  end

  edits = [FixEdit.new(start_line: line_idx, start_char: new_start, end_line: line_idx, end_char: arrow_end, new_text: "")]

  if arrow_end < line.length && line[arrow_end] == "("
    close_paren = match_paren(line, arrow_end)
    if close_paren && !inner_has_top_level_operators?(line[arrow_end + 1...close_paren])
      edits << FixEdit.new(start_line: line_idx, start_char: arrow_end, end_line: line_idx, end_char: arrow_end + 1, new_text: "")
      edits << FixEdit.new(start_line: line_idx, start_char: close_paren, end_line: line_idx, end_char: close_paren + 1, new_text: "")
    end
  end

  edits
end

.redundant_else_edits(lines, warning) ⇒ Object 



113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 113

def self.redundant_else_edits(lines, warning)
  return [] unless warning.line

  diag_idx = warning.line - 1
  return [] if diag_idx.negative?

  if lines[diag_idx]&.match?(/\A\s*else:\s*\z/)
    else_idx = diag_idx
    first_body_idx = else_idx + 1
  else
    first_body_idx = diag_idx
    return [] if first_body_idx < 1

    else_idx = (0...first_body_idx).to_a.reverse.find { |i| lines[i]&.match?(/\A\s*else:\s*\z/) }
  end
  return [] unless else_idx
  return [] if first_body_idx >= lines.length

  else_indent = lines[else_idx].match(/\A(\s*)/)[1]
  body_indent = "#{else_indent}    "

  body_end_idx = first_body_idx
  (first_body_idx...lines.length).each do |i|
    l = lines[i]
    if l.chomp.empty? || l.start_with?(body_indent)
      body_end_idx = i
    else
      break
    end
  end

  new_body = lines[first_body_idx..body_end_idx].map { |l| l.sub(/\A    /, "") }.join
  [FixEdit.new(start_line: else_idx, start_char: 0, end_line: body_end_idx + 1, end_char: 0, new_text: new_body)]
end

.redundant_ignored_match_binding_edits(lines, warning) ⇒ Object 



69
70
71
72
73
74
75
76
77
78
79
80
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 69

def self.redundant_ignored_match_binding_edits(lines, warning)
  return [] unless warning.line && warning.column

  line_idx = warning.line - 1
  line = lines[line_idx]
  return [] unless line

  span = Linter.redundant_ignored_match_binding_span(line, column: warning.column)
  return [] unless span

  [FixEdit.new(start_line: line_idx, start_char: span[:start_char], end_line: line_idx, end_char: span[:end_char], new_text: "")]
end

.redundant_return_edits(lines, warning) ⇒ Object 



148
149
150
151
152
153
154
155
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 148

def self.redundant_return_edits(lines, warning)
  return [] unless warning.line

  line_idx = warning.line - 1
  return [] unless lines[line_idx]&.match?(/\A\s*return\s*\z/)

  [FixEdit.new(start_line: line_idx, start_char: 0, end_line: line_idx + 1, end_char: 0, new_text: "")]
end

.redundant_type_annotation_edits(lines, warning) ⇒ Object 



225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 225

def self.redundant_type_annotation_edits(lines, warning)
  return [] unless warning.line

  line_idx = warning.line - 1
  line = lines[line_idx]
  return [] unless line

  name_len = warning.length
  col = warning.column - 1
  return [] if col.negative? || col + name_len > line.length

  after_name = col + name_len
  rest = line[after_name..]
  return [] unless rest

  type_match = rest.match(/\s*:\s*\S+/)
  return [] unless type_match

  new_line = +"#{line[0...after_name]}#{rest[type_match.end(0)..]}"
  [FixEdit.new(start_line: line_idx, start_char: 0, end_line: line_idx + 1, end_char: 0, new_text: new_line)]
end

.redundant_unsafe_edits(lines, warning) ⇒ Object

── redundant-unsafe ─────────────────────────────────────────────────── Removes an unsafe: wrapper that contains no unsafe operations.

Supported shapes:

<indent>unsafe:\n<deeper body>   (block statement; body is dedented)
... unsafe: expr ...             (inline expression on a single line)


312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 312

def self.redundant_unsafe_edits(lines, warning)
  return [] unless warning.line

  line_idx = warning.line - 1
  line = lines[line_idx]
  return [] unless line

  unsafe_idx = line.index("unsafe:")
  return [] unless unsafe_idx

  keyword_end = unsafe_idx + "unsafe:".length
  rest = line[keyword_end..]

  if rest && !rest.strip.empty?
    # Inline expression form: drop the keyword and the whitespace after
    # it, but only when the remainder is balanced on this line.
    remainder = rest.sub(/\A\s+/, "")
    return [] if remainder.empty? || !balanced_line?(remainder)

    return [FixEdit.new(
      start_line: line_idx,
      start_char: unsafe_idx,
      end_line: line_idx,
      end_char: keyword_end + (rest.length - remainder.length),
      new_text: "",
    )]
  end

  # Block statement form: `unsafe:` alone, body indented deeper.
  indent = line[0...unsafe_idx]
  return [] unless indent.match?(/\A *\z/)

  body_start = line_idx + 1
  body_indent = nil
  last_body = nil
  (body_start...lines.length).each do |i|
    candidate = lines[i]
    if candidate.nil? || candidate.strip.empty?
      last_body = i
      next
    end

    break unless candidate.start_with?(indent + " ")

    body_indent ||= candidate[/\A */].length - indent.length
    last_body = i
  end

  return [] if last_body.nil? || last_body < body_start
  return [] if body_indent.nil? || body_indent <= 0
  return [] unless (body_start..last_body).all? do |i|
    l = lines[i]
    l.nil? || l.strip.empty? || l.start_with?(indent + " " * body_indent)
  end

  replacement = (body_start..last_body).map do |i|
    l = lines[i]
    l.nil? || l.strip.empty? ? "" : l[body_indent..].to_s.chomp
  end

  if last_body + 1 <= lines.length - 1
    # Consume through the first following line; apply_fix_edits re-emits
    # it as the suffix of a multi-line replacement.
    end_line = last_body + 1
    end_char = 0
  else
    end_line = last_body
    end_char = lines[last_body].to_s.length
  end

  [FixEdit.new(
    start_line: line_idx,
    start_char: 0,
    end_line:,
    end_char:,
    new_text: replacement.join("\n") + "\n",
  )]
end

.start_of_expression?(inner, pos) ⇒ Boolean

Returns:

  • (Boolean) 


439
440
441
442
443
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 439

def self.start_of_expression?(inner, pos)
  return true if pos == 0
  prev = pos - 1
  prev >= 0 && (inner[prev] == " " || inner[prev] == "\t" || inner[prev] == "(")
end

.trailing_list_comma_edits(lines, warning) ⇒ Object 



211
212
213
214
215
216
217
218
219
220
221
222
223
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 211

def self.trailing_list_comma_edits(lines, warning)
  return [] unless warning.line && warning.column

  line_idx = warning.line - 1
  line = lines[line_idx]
  return [] unless line

  char_idx = warning.column - 1
  return [] if char_idx.negative? || char_idx >= line.length
  return [] unless line[char_idx] == ","

  [FixEdit.new(start_line: line_idx, start_char: char_idx, end_line: line_idx, end_char: char_idx + 1, new_text: "")]
end

.unused_import_edits(lines, warning) ⇒ Object 



202
203
204
205
206
207
208
209
 
# File 'lib/milk_tea/tooling/linter/fix_engine.rb', line 202

def self.unused_import_edits(lines, warning)
  return [] unless warning.line

  line_idx = warning.line - 1
  return [] unless lines[line_idx]&.match?(/\A\s*import\b/)

  [FixEdit.new(start_line: line_idx, start_char: 0, end_line: line_idx + 1, end_char: 0, new_text: "")]
end