Implement separate limits for line length based on line type

Like for trailing whitespace warnings, separate
lines with line endings within a comment, a string, or normal code lines.
Add separate limits for line length for these three types.
Main option (max_line_length) sets max length for all three types.

Ref #100.

spec/check_spec.lua

@@ -908,7 +908,8 @@ return foo;
          per_line_options = {
             [2] = {{options = {ignore = {"foo"}}, line = 2, column = 16, end_column = 38}}
          },
-         line_lengths = {28, 38, 16, 17, 19, 17, 32, 16, 3}
+         line_lengths = {28, 38, 16, 17, 19, 17, 32, 16, 3},
+         line_endings = {"comment", "comment", "comment", nil, "comment", "comment", nil, "comment", nil}
       }, check_full[[
 -- luacheck: push ignore bar
 local foo, bar -- luacheck: ignore foo

spec/cli_spec.lua

@@ -550,33 +550,58 @@ Total: 6 warnings / 0 errors in 1 file
 
    it("detects lines that are too long", function()
       assert.equal([[
-Checking spec/samples/line_length.lua             4 warnings
+Checking spec/samples/line_length.lua             8 warnings
 
     spec/samples/line_length.lua:2:1: line is too long (123 > 120)
     spec/samples/line_length.lua:3:1: line is too long (164 > 120)
-    spec/samples/line_length.lua:8:1: line is too long (132 > 120)
-    spec/samples/line_length.lua:10:1: line is too long (85 > 80)
-
-Total: 4 warnings / 0 errors in 1 file
+    spec/samples/line_length.lua:8:1: line is too long (134 > 120)
+    spec/samples/line_length.lua:13:1: line is too long (47 > 40)
+    spec/samples/line_length.lua:18:1: line is too long (132 > 120)
+    spec/samples/line_length.lua:22:1: line is too long (85 > 80)
+    spec/samples/line_length.lua:26:1: line is too long (104 > 100)
+    spec/samples/line_length.lua:29:1: line is too long (125 > 120)
+
+Total: 8 warnings / 0 errors in 1 file
 ]], get_output "spec/samples/line_length.lua --no-config")
 
       assert.equal([[
-Checking spec/samples/line_length.lua             3 warnings
+Checking spec/samples/line_length.lua             7 warnings
 
     spec/samples/line_length.lua:3:1: line is too long (164 > 130)
-    spec/samples/line_length.lua:8:1: line is too long (132 > 130)
-    spec/samples/line_length.lua:10:1: line is too long (85 > 80)
+    spec/samples/line_length.lua:8:1: line is too long (134 > 130)
+    spec/samples/line_length.lua:13:1: line is too long (47 > 40)
+    spec/samples/line_length.lua:18:1: line is too long (132 > 130)
+    spec/samples/line_length.lua:22:1: line is too long (85 > 80)
+    spec/samples/line_length.lua:26:1: line is too long (104 > 100)
+    spec/samples/line_length.lua:29:1: line is too long (125 > 120)
 
-Total: 3 warnings / 0 errors in 1 file
+Total: 7 warnings / 0 errors in 1 file
 ]], get_output "spec/samples/line_length.lua --no-config --max-line-length=130")
 
       assert.equal([[
-Checking spec/samples/line_length.lua             1 warning
+Checking spec/samples/line_length.lua             4 warnings
 
-    spec/samples/line_length.lua:10:1: line is too long (85 > 80)
+    spec/samples/line_length.lua:13:1: line is too long (47 > 40)
+    spec/samples/line_length.lua:22:1: line is too long (85 > 80)
+    spec/samples/line_length.lua:26:1: line is too long (104 > 100)
+    spec/samples/line_length.lua:29:1: line is too long (125 > 120)
 
-Total: 1 warning / 0 errors in 1 file
+Total: 4 warnings / 0 errors in 1 file
 ]], get_output "spec/samples/line_length.lua --no-config --no-max-line-length")
+
+      assert.equal([[
+Checking spec/samples/line_length.lua             7 warnings
+
+    spec/samples/line_length.lua:2:1: line is too long (123 > 120)
+    spec/samples/line_length.lua:3:1: line is too long (164 > 120)
+    spec/samples/line_length.lua:13:1: line is too long (47 > 40)
+    spec/samples/line_length.lua:18:1: line is too long (132 > 120)
+    spec/samples/line_length.lua:22:1: line is too long (85 > 80)
+    spec/samples/line_length.lua:26:1: line is too long (104 > 100)
+    spec/samples/line_length.lua:29:1: line is too long (125 > 120)
+
+Total: 7 warnings / 0 errors in 1 file
+]], get_output "spec/samples/line_length.lua --no-config --no-max-string-line-length")
    end)
 
    it("detects issues related to read-only globals", function()
@@ -884,10 +909,10 @@ Total: 16 warnings / 1 error in 4 files
 (%d+)
 spec/samples/good_code.lua
 (%d+)
-return {{},{},{19,0,23,17,3,0,30,25,26,3,0,15}}
+return {{},{},{19,0,23,17,3,0,30,25,26,3,0,15},{[4]="comment"}}
 spec/samples/bad_code.lua
 (%d+)
-local A,B,C="package","embrace","hepler";return {{{"112",A,1,1,7,[23]={A,"loaded",true}},{"211","helper",3,16,21,[10]=true},{"212","...",3,23,25},{"111",B,7,10,16,[11]=true,[23]={B}},{"412","opt",8,10,12,7,18},{"113",C,9,11,16,[23]={C}}},{},{24,0,26,9,3,0,21,31,26,3,0}}
+local A,B,C="package","embrace","hepler";return {{{"112",A,1,1,7,[23]={A,"loaded",true}},{"211","helper",3,16,21,[10]=true},{"212","...",3,23,25},{"111",B,7,10,16,[11]=true,[23]={B}},{"412","opt",8,10,12,7,18},{"113",C,9,11,16,[23]={C}}},{},{24,0,26,9,3,0,21,31,26,3,0},{[4]="comment"}}
 spec/samples/python_code.lua
 (%d+)
 return {{{"011",[3]=1,[4]=6,[5]=15,[12]="expected '=' near '__future__'"}},{},{}}
@@ -1209,15 +1234,15 @@ Checking spec/samples/global_inline_options.lua   3 warnings
 Checking spec/samples/globals.lua                 2 warnings
 Checking spec/samples/indirect_globals.lua        3 warnings
 Checking spec/samples/inline_options.lua          7 warnings / 2 errors
-Checking spec/samples/line_length.lua             4 warnings
+Checking spec/samples/line_length.lua             8 warnings
 Checking spec/samples/python_code.lua             1 error
 Checking spec/samples/read_globals.lua            5 warnings
 Checking spec/samples/read_globals_inline_options.lua 3 warnings
 Checking spec/samples/redefined.lua               7 warnings
 Checking spec/samples/unused_code.lua             9 warnings
 Checking spec/samples/unused_secondaries.lua      4 warnings
 
-Total: 63 warnings / 4 errors in 16 files
+Total: 67 warnings / 4 errors in 16 files
 ]]):gsub("(spec/samples)/", "%1"..package.config:sub(1, 1)),
             get_output "spec/samples --config=spec/configs/exclude_files_config.luacheckrc -qq --exclude-files spec/samples/global_fields.lua")
          end)
@@ -1231,15 +1256,15 @@ Checking global_inline_options.lua                3 warnings
 Checking globals.lua                              2 warnings
 Checking indirect_globals.lua                     3 warnings
 Checking inline_options.lua                       7 warnings / 2 errors
-Checking line_length.lua                          4 warnings
+Checking line_length.lua                          8 warnings
 Checking python_code.lua                          1 error
 Checking read_globals.lua                         5 warnings
 Checking read_globals_inline_options.lua          3 warnings
 Checking redefined.lua                            7 warnings
 Checking unused_code.lua                          9 warnings
 Checking unused_secondaries.lua                   4 warnings
 
-Total: 63 warnings / 4 errors in 16 files
+Total: 67 warnings / 4 errors in 16 files
 ]], get_output(". --config=spec/configs/exclude_files_config.luacheckrc -qq --exclude-files global_fields.lua", "spec/samples/"))
          end)
 
@@ -1252,13 +1277,13 @@ Checking global_inline_options.lua                3 warnings
 Checking globals.lua                              2 warnings
 Checking indirect_globals.lua                     3 warnings
 Checking inline_options.lua                       7 warnings / 2 errors
-Checking line_length.lua                          4 warnings
+Checking line_length.lua                          8 warnings
 Checking python_code.lua                          1 error
 Checking redefined.lua                            7 warnings
 Checking unused_code.lua                          9 warnings
 Checking unused_secondaries.lua                   4 warnings
 
-Total: 55 warnings / 4 errors in 14 files
+Total: 59 warnings / 4 errors in 14 files
 ]], get_output(". --config=spec/configs/exclude_files_config.luacheckrc -qq --exclude-files global_fields.lua --exclude-files " .. quote("./read*"), "spec/samples/"))
          end)
 

spec/filter_spec.lua

@@ -638,16 +638,18 @@ describe("filter", function()
       assert.same({
          {
             {code = "631", line = 2, column = 1, end_column = 121, max_length = 120},
-            {code = "631", line = 5, column = 1, end_column = 21, max_length = 20}
+            {code = "631", line = 5, column = 1, end_column = 18, line_ending = "string", max_length = 15}
          }
       }, filter_full({
          {
             events = {
                {options = {max_line_length = 20}, line = 3, column = 1},
+               {options = {max_string_line_length = 15}, line = 4, column = 1},
                {options = {max_line_length = false}, line = 6, column = 1}
             },
             per_line_options = {},
-            line_lengths = {120, 121, 15, 20, 21, 15, 200}
+            line_lengths = {120, 121, 15, 20, 18, 15, 200},
+            line_endings = {[5] = "string"}
          }
       }, {}))
    end)

spec/samples/line_length.lua

@@ -1,11 +1,30 @@
 -- luacheck: only 63
 local aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 ------------------------------------------------------------------------------------------------------------------------------------------ comments can be long, too
--- luacheck: push no max line length
+
+-- luacheck: push no max code line length
 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa = "readable code"
+string = [[
+looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong
+]]
 normal = "still normal"
+
+-- luacheck: push max line length 40
+this_overrides_code_line_specific_option = true
 -- luacheck: pop
+
+-- luacheck: pop
+
 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa = "unreadable"
 -- luacheck: max line length 80
+-- luacheck: max string line length 100
+-- luacheck: max comment line length 120
 local i_code_in_ed_in_a_terminal_with_default_width_and_i_dont_like_long_lines = true
 local really = false
+string2 = [[kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk94
+]]
+string3 = [[kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk105
+]]
+code() -- comment kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk105
+--[[ comment kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk125
+]]

src/luacheck/cache.lua

@@ -9,13 +9,13 @@ local cache = {}
 -- third is check result in lua table format.
 -- String fields are compressed into array indexes.
 
-cache.format_version = 19
+cache.format_version = 20
 
 local option_fields = {
    "ignore", "std", "globals", "unused_args", "self", "compat", "global", "unused", "redefined",
    "unused_secondaries", "allow_defined", "allow_defined_top", "module",
    "read_globals", "new_globals", "new_read_globals", "enable", "only", "not_globals",
-   "max_line_length"
+   "max_line_length", "max_code_line_length", "max_string_line_length", "max_comment_line_length"
 }
 
 local event_fields = {
@@ -55,6 +55,7 @@ local function compress_report(report)
    end
 
    res[3] = report.line_lengths
+   res[4] = report.line_endings
    return res
 end
 
@@ -88,6 +89,7 @@ local function decompress_report(compressed)
    end
 
    report.line_lengths = compressed[3]
+   report.line_endings = compressed[4]
    return report
 end
 

src/luacheck/check.lua

@@ -238,7 +238,7 @@ local function check_or_throw(src)
    reachability(chstate, line)
    detect_globals(chstate, line)
    local events, per_line_opts = inline_options.get_events(ast, comments, code_lines, chstate.warnings)
-   return {events = events, per_line_options = per_line_opts, line_lengths = line_lengths}
+   return {events = events, per_line_options = per_line_opts, line_lengths = line_lengths, line_endings = line_endings}
 end
 
 --- Checks source.

src/luacheck/filter.lua

@@ -259,9 +259,17 @@ local function get_field_status(opts, warning, depth)
    return defined and (read_only and "read_only" or "global") or "undefined"
 end
 
+local function get_max_line_length(opts, warning)
+   return opts["max_" .. (warning.line_ending or "code") .. "_line_length"]
+end
+
 local function filters(opts, warning)
-   if warning.code == "631" and (not opts.max_line_length or warning.end_column <= opts.max_line_length) then
-      return true
+   if warning.code == "631" then
+      local max_line_length = get_max_line_length(opts, warning)
+
+      if (not max_line_length or warning.end_column <= max_line_length) then
+         return true
+      end
    end
 
    if warning.code:match("[234]..") and warning.name == "_" and not warning.useless then
@@ -309,7 +317,7 @@ local function filter_file_report(report)
       else
          if not filters(opts, issue) then
             if issue.code == "631" then
-               issue.max_length = opts.max_line_length
+               issue.max_length = get_max_line_length(opts, issue)
             end
 
             if issue.code:match("1[24][23]") then
@@ -420,6 +428,7 @@ local function add_long_line_warnings(report)
                code = "631",
                line = line_number,
                column = 1,
+               line_ending = file_report.line_endings[line_number],
                end_column = length
             })
          end

src/luacheck/inline_options.lua

@@ -33,6 +33,9 @@ local function add_closure_boundaries(ast, events)
    end
 end
 
+local max_line_length_opts = utils.array_to_set({
+   "max_line_length", "max_code_line_length", "max_string_line_length", "max_comment_line_length"})
+
 -- Parses inline option body, returns options or nil.
 local function get_options(body)
    local opts = {}
@@ -70,13 +73,13 @@ local function get_options(body)
                   -- Array option with 'no' prefix is invalid.
                   return
                end
-            elseif name == "max_line_length" then
-               -- Either `max line length <number>` or `no max line length`.
+            elseif max_line_length_opts[name] then
+               -- Either `max [type] line length <number>` or `no max [type] line length`.
                if flag and #args == 1 and tonumber(args[1]) then
-                  opts.max_line_length = tonumber(args[1])
+                  opts[name] = tonumber(args[1])
                   break
                elseif not flag and #args == 0 then
-                  opts.max_line_length = false
+                  opts[name] = false
                   break
                else
                   return

src/luacheck/main.lua

@@ -129,6 +129,30 @@ their files.]])
          :action "store_false"
          :target "max_line_length"
 
+      parser:option("--max-code-line-length", [[Set maximum allowed length for lines
+ending with code (default: 120).]])
+         :argname "<length>"
+         :convert(tonumber)
+      parser:flag("--no-max-code-line-length", "Do not limit code line length.")
+         :action "store_false"
+         :target "max_code_line_length"
+
+      parser:option("--max-string-line-length", [[Set maximum allowed length for lines
+within a string (default: 120).]])
+         :argname "<length>"
+         :convert(tonumber)
+      parser:flag("--no-max-string-line-length", "Do not limit string line length.")
+         :action "store_false"
+         :target "max_string_line_length"
+
+      parser:option("--max-comment-line-length", [[Set maximum allowed length for
+comment lines (default: 120).]])
+         :argname "<length>"
+         :convert(tonumber)
+      parser:flag("--no-max-comment-line-length", "Do not limit comment line length.")
+         :action "store_false"
+         :target "max_comment_line_length"
+
       parser:option("--ignore -i", [[Filter out warnings matching these patterns.
 If a pattern contains slash, part before slash matches
 warning code and part after it matches name of related

src/luacheck/options.lua

@@ -78,6 +78,9 @@ options.variadic_inline_options = {
 options.all_options = {
    std = std_or_array_of_strings,
    max_line_length = number_or_false,
+   max_code_line_length = number_or_false,
+   max_string_line_length = number_or_false,
+   max_comment_line_length = number_or_false,
    inline = boolean
 }
 
@@ -259,6 +262,34 @@ local function get_scalar_opt(opts_stack, option, default)
    return default
 end
 
+local line_length_suboptions = {"max_code_line_length", "max_string_line_length", "max_comment_line_length"}
+
+local function get_max_line_opts(opts_stack)
+   local res = {max_line_length = 120}
+
+   for _, opt_name in ipairs(line_length_suboptions) do
+      res[opt_name] = res.max_line_length
+   end
+
+   for _, opts in ipairs(opts_stack) do
+      if opts.max_line_length ~= nil then
+         res.max_line_length = opts.max_line_length
+
+         for _, opt_name in ipairs(line_length_suboptions) do
+            res[opt_name] = opts.max_line_length
+         end
+      end
+
+      for _, opt_name in ipairs(line_length_suboptions) do
+         if opts[opt_name] ~= nil then
+            res[opt_name] = opts[opt_name]
+         end
+      end
+   end
+
+   return res
+end
+
 local function anchor_pattern(pattern, only_start)
    if not pattern then
       return
@@ -361,8 +392,7 @@ local scalar_options = {
    inline = true,
    module = false,
    allow_defined = false,
-   allow_defined_top = false,
-   max_line_length = 120
+   allow_defined_top = false
 }
 
 -- Returns normalized options.
@@ -379,6 +409,8 @@ function options.normalize(opts_stack)
       res[option] = get_scalar_opt(opts_stack, option, default)
    end
 
+   local max_line_opts = get_max_line_opts(opts_stack)
+   utils.update(res, max_line_opts)
    res.rules = normalize_patterns(get_rules(opts_stack))
    return res
 end