feat(core): Add command stack system for better error output

Document location traces are printed on error, and if -t is enabled, also on warning. Also print stack traces on SU.error.
sile-typesetter · May 3, 2019 · edafe1e · edafe1e
1 parent a30fb05
commit edafe1e
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Showing 5 changed files with 284 additions and 13 deletions.
diff --git a/core/inputs-common.lua b/core/inputs-common.lua
@@ -55,17  55,22 @@ SILE.process = function(input)
   if SU.debugging("ast") then
     debugAST(input,0)
   end
 
   for i=1, #input do
-    SILE.currentCommand = input[i]
     local content = input[i]
 
     if type(content) == "string" then
       SILE.typesetter:typeset(content)
     elseif SILE.Commands[content.tag] then
       SILE.call(content.tag, content.attr, content)
     elseif content.id == "texlike_stuff" or (not content.tag and not content.id) then
       local pId = SILE.currentCommandStack:pushContent(content, "texlike_stuff")
       SILE.process(content)
       SILE.currentCommandStack:pop(pId)
     else
       local pId = SILE.currentCommandStack:pushContent(content)
       SU.error("Unknown command "..(content.tag or content.id))
       SILE.currentCommandStack:pop(pId)
     end
   end
 end

diff --git a/core/inputs-xml.lua b/core/inputs-xml.lua
@@ -16,7  16,7 @@ SILE.inputs.XML = {
       end
       SILE.inputs.common.init(doc, content)
     end
-    SILE.currentCommand = content
 
     if SILE.Commands[content.tag] then
       SILE.call(content.tag, content.attr, content)
     else

diff --git a/core/sile.lua b/core/sile.lua
@@ -132,6  132,7 @@ Options:
   -- http://lua-users.org/wiki/VarargTheSecondClassCitizen
   local identity = function (...) return unpack({...}, 1, select('#', ...)) end
   SILE.errorHandler = opts.traceback and debug.traceback or identity
   SILE.detailedErrors = not not opts.traceback
 end
 
 function SILE.initRepl ()
@@ -240,10  241,250 @@ function SILE.resolveFile(filename, pathprefix)
   return nil
 end
 
 SILE.currentCommandStack = {
   --- Internal: push-pop balance checking ID
   _lastPushId = 0,
   --- Internal: Function assigned to frames to convert them to string
   _frameToString = function(self, skipFile, withAttrs)
     local str
     if skipFile or not self.file then
       str = ""
     else
       str = self.file .. " "
     end
 
     if self.line then
       str = str .. "l." .. self.line .. " "
       if self.column then
         str = str .. "col." .. self.column .. " "
       end
     end
 
     if self.tag then
       -- Command
       str = str .. "\\" .. self.tag
       if withAttrs then
         str = str .. "["
         local first = true
         for key, value in pairs(self.options) do
           if first then first = false else str = str .. ", " end
           str = str .. key .. "=" .. value
         end
         str = str .. "]"
       end
     elseif self.text then
       -- Literal string
       local text = self.text
       if text:len() > 20 then
         text = text:sub(1, 18) .. "…"
       end
       text = text:gsub("\n", "␤"):gsub("\t", "␉"):gsub("\v", "␋")
 
       str = str .. "\"" .. text .. "\""
     else
       -- Unknown
       str = str .. type(self.content) .. "(" .. self.content .. ")"
     end
 
     --str = str .. "\n\n" .. self.pushTrace .. "\n"
 
     return str
   end
 }
 --- Push a command frame on to the stack to record the execution trace for debugging.
 --- Carries information about the command call, not the command itself.
 --- Must be popped with `pop(returnOfPush)`.
 function SILE.currentCommandStack:pushCommand(tag, line, column, options, file)
   return self:_pushFrame({
     tag = tag or "???",
     file = file or SILE.currentlyProcessingFile,
     line = line,
     column = column,
     options = options or {}
   })
 end
 --- Push a command frame on to the stack to record the execution trace for debugging.
 --- Command arguments are inferred from AST content, any item may be overridden.
 --- Must be popped with `pop(returnOfPush)`.
 function SILE.currentCommandStack:pushContent(content, tag, line, column, options, file)
   return self:_pushFrame({
     tag = tag or (type(content) == "table" and content.tag) or "???",
     file = file or SILE.currentlyProcessingFile,
     line = line or (type(content) == "table" and content.line),
     column = column or (type(content) == "table" and content.col),
     options = options or (type(content) == "table" and content.attr) or {}
   })
 end
 --- Push a text that is going to get typeset on to the stack to record the execution trace for debugging.
 --- Must be popped with `pop(returnOfPush)`.
 function SILE.currentCommandStack:pushText(text, line, column, file)
   return self:_pushFrame({
     text = text,
     file = file,
     line = line,
     column = column
   })
 end
 --- Internal: Push complete frame
 function SILE.currentCommandStack:_pushFrame(frame)
   frame.toString = self._frameToString
   frame.typesetter = SILE.typesetter
   --frame.pushTrace = debug.traceback(nil, 3)
 
   -- Push the frame
   if SU.debugging("commandStack") then
     print(string.rep(" ", #self) .. "PUSH(" .. frame:toString(false, true) .. ")")
   end
   self[#self   1] = frame
   self.lastCommand = nil
   self._lastPushId = self._lastPushId   1
   frame.pushId = self._lastPushId
   return self._lastPushId
 end
 --- Pop previously pushed command from the stack.
 --- Return value of `push` function must be provided as argument to check for balanced usage.
 function SILE.currentCommandStack:pop(pushId)
   if type(pushId) ~= "number" then
     SU.error("SILE.currentCommandStack:pop's argument must be the result value of the corresponding push", true)
   end
 
   -- First verify that push/pop is balanced
   local popped = self[#self]
   if popped.pushId ~= pushId then
     local message = "Unbalanced content push/pop"
     local debug = SILE.detailedErrors or SU.debugging("commandStack")
     if debug then
       message = message .. ". Expected " .. popped.pushId .. " - (" .. popped:toString() .. "), got " .. pushId
     end
     SU.warn(message, debug)
   else
     -- Correctly balanced: pop the frame
     self.lastCommand = popped
     self[#self] = nil
     if SU.debugging("commandStack") then
       print(string.rep(" ", #self) .. "POP(" .. popped:toString(false, true) .. ")")
     end
   end
 end
 --- Returns a stack of commands, which can be used to show information about location in document.
 --- Most relevant object is in the last index.
 --- Second return: recently popped value which could provide extra location information
 function SILE.currentCommandStack:locationStack(currentTypesetterOnly)
   local result = {}
 
   for i = 1, #self do
     if not currentTypesetterOnly or (self[i].typesetter == SILE.typesetter) then
       result[#result   1] = self[i]
     end
   end
 
   local extra = self.lastCommand
   if (not extra) -- skip other checks if extra is nil
           or extra == result[#result] -- no extra if it already is on the stack
           or (currentTypesetterOnly and (extra.typesetter ~= SILE.typesetter)) -- no extra if wrong typesetter
   then
     extra = nil
   end
 
   return result, extra
 end
 
 --- Internal: Format top of the stack from locationStack(), may return nil
 function SILE.currentCommandStack:_locationTraceEntry(stack, after)
   -- Stack may contain mix of tables and strings.
   -- We hope to get a table, because that contains position information.
   -- A string may also be useful, but preferably with a table as well.
   local top = stack[#stack]
 
   if not top then
     -- Stack is empty, there is not much we can do
     if after then
       return "after " .. after:toString()
     else
       return nil
     end
   end
 
   local base -- real content frame with location information
   local string -- string being typeset, closer to the real problem, but has no location information
   if type(top.content) == "table" then
     base = top
     string = nil
   else
     string = top
     for i = #stack - 1, 1, -1 do
       if type(stack[i].content) == "table" then
         base = stack[i]
         break
       end
     end
   end
 
   -- Join
   local info
   if not string then
     info = base:toString()
   else
     info = string:toString()
     if base then
       info = info .. " near " .. base:toString(--[[skipFile=]] base.file == string.file)
     end
   end
 
   -- Print after, if it is in a relevant file
   if after and (not base or after.file == base.file) then
     info = info .. " after " .. after:toString(--[[skipFile=]] true)
   end
 
   return info
 end
 --- Returns short string with most relevant location information for user messages.
 function SILE.currentCommandStack:locationInfo()
   local stack, after = self:locationStack()
   return self:_locationTraceEntry(stack, after) or SILE.currentlyProcessingFile or "<nowhere>"
 end
 --- Returns multiline trace string, with full document location information for user messages.
 function SILE.currentCommandStack:locationTrace()
   local stack, after = self:locationStack()
 
   local prefix = "  at "
   local trace = self:_locationTraceEntry({ stack[#stack] } --[[we handle rest of the stack ourselves]], after)
   if not trace then
     -- There is nothing else then
     return prefix .. (SILE.currentlyProcessingFile or "<nowhere>") .. "\n"
   end
   trace = prefix .. trace .. "\n"
 
   -- Iterate backwards, skipping the last element
   for i = #stack - 1, 1, -1 do
     local s = stack[i]
     trace = trace .. prefix .. s:toString() .. "\n"
   end
 
   return trace
 end
 
 function SILE.call(cmd, options, content)
-  SILE.currentCommand = content
   -- Prepare trace information for command stack
   local file, line, column
   if SILE.detailedErrors and not (type(content) == "table" and content.line) then
     -- This call is from code (no content.line) and we want to spend the time
     -- to determine everything we need about the caller
     local caller = debug.getinfo(2, "Sl")
     file = caller.short_src
     line = caller.currentline
   elseif type(content) == "table" then
     line = content.line
     column = content.col
   end
 
   local pId = SILE.currentCommandStack:pushCommand(cmd, line, column, options, file)
 
   if not SILE.Commands[cmd] then SU.error("Unknown command "..cmd) end
-  return SILE.Commands[cmd](options or {}, content or {})
   local result = SILE.Commands[cmd](options or {}, content or {})
 
   SILE.currentCommandStack:pop(pId)
   return result
 end
 
 return SILE
diff --git a/core/typesetter.lua b/core/typesetter.lua
@@ -183,13  183,16 @@ SILE.defaultTypesetter = std.object {
   -- Actual typesetting functions
   typeset = function (self, text)
     if text:match("^%\r?\n$") then return end
 
     local pId = SILE.currentCommandStack:pushText(text)
     for token in SU.gtoke(text,SILE.settings.get("typesetter.parseppattern")) do
       if (token.separator) then
         self:endline()
       else
         self:setpar(token.string)
       end
     end
     SILE.currentCommandStack:pop(pId)
   end,
 
   initline = function (self)

diff --git a/core/utilities.lua b/core/utilities.lua
@@ -25,21  25,43 @@ if not table.maxn then
   end
 end
 
-utilities.error = function (message, bug)
-  if(SILE.currentCommand and type(SILE.currentCommand) == "table") then
-    io.stderr:write("\n! "..message.. " at "..SILE.currentlyProcessingFile.." l."..(SILE.currentCommand.line)..", col."..(SILE.currentCommand.col))
 utilities.error = function(message, bug)
   io.stderr:write("\n! " .. message)
   if not SILE.detailedErrors and not bug then
     -- Normal operation, show only inline info
     io.stderr:write(" at " .. SILE.currentCommandStack:locationInfo())
     io.stderr:write("\n")
   else
-    io.stderr:write("\n! "..message.. " at "..SILE.currentlyProcessingFile)
     -- Using full error handler, print whole trace
     io.stderr:write("\n")
     io.stderr:write(SILE.currentCommandStack:locationTrace())
     io.stderr:write(debug.traceback(nil, 2))
     io.stderr:write("\n")
   end
-  if bug then io.stderr:write(debug.traceback()) end
-  io.stderr:write("\n")
   io.stderr:flush()
 
   SILE.outputter:finish()
   os.exit(1)
 end
 
-utilities.warn = function (message)
-  io.stderr:write("\n! "..message.."\n")
-  --print(debug.traceback())
 utilities.warn = function (message, bug)
   io.stderr:write("\n! "..message)
   if not (SILE.detailedErrors or bug) then
     -- Normal operation, show only inline info
     io.stderr:write(" at "..SILE.currentCommandStack:locationInfo())
     io.stderr:write("\n")
   else
     -- Show full trace
     io.stderr:write("\n")
     io.stderr:write(SILE.currentCommandStack:locationTrace())
   end
 
   if bug then
     -- Something weird has happened, but the program can continue
     io.stderr:write(debug.traceback(nil, 2))
     io.stderr:write("\n")
   end
 
   --os.exit(1)
 end