add resolve tree in failed resolution errors, closes #24

moonbuild/core/DAG.moon

@@ -56,22 +56,44 @@ class DepGraph
 
 	addnode: (name) =>
 		return if @nodes[name]
-		elected = @resolvedeps name
+		elected = @topresolvedeps name
 		@nodes[name] = elected
 		for dep in *(transclosure elected, 'deps')
 			@nodes[dep.name] = dep
 			dep.deps = nil
 		elected.deps = nil
 
-	resolvedeps: (name) =>
+	topresolvedeps: (name) =>
+		errors = {}
+		ok, rst = pcall -> @resolvedeps name, nil, errors
+		if ok
+			rst
+		else
+			msg = {"Failed to resolve target \'#{name}\'\n"}
+			for e in *errors
+				if e.err\match '^moonbuild'
+					e.err = e.err\match ': (.+)$'
+			for i=#errors, 1, -1
+				e = errors[i]
+				insert msg, "#{string.rep '| ', e.level - 1}+-[#{e.name}] level #{e.level}: #{e.err}"
+			insert msg, ''
+			error table.concat msg, '\n'
+
+	resolvedeps: (name, level=1, errors={}) =>
 		do
 			node = @nodes[name]
-			return node, {} if node
+			if node
+				print "deps(#{name}) = #{node.name or '[noname]'}"
+				return node, {}
 		candidates = filter {@ctx.targets, FileTarget!}, (target) -> target\matches name
-		nodes = foreach candidates, (candidate) -> a: {pcall -> DepNode @, candidate, name}
+		nodes = foreach candidates, (candidate) -> a: {pcall -> DepNode @, candidate, name, level, errors}
 		resolved = foreach (filter nodes, (node) -> node.a[1]), (node) -> node.a[2]
 		sort resolved, nodepriority
-		resolved[1] or error "Cannot resolve target #{name}: #{#candidates} candidates, #{#resolved} resolved"
+		unless resolved[1]
+			err = "Cannot resolve target #{name}: #{#candidates} candidates, #{#resolved} resolved"
+			table.insert errors, {:name, :level, :err}
+			error err
+		resolved[1]
 
 	buildablenodes: =>
 		[v for k, v in pairs @nodes when v\canbuild! and not v.built]
@@ -91,7 +113,7 @@ class DepGraph
 			insert stack, n for n in *(node\children!)
 
 class DepNode
-	new: (@dag, target, @name) =>
+	new: (@dag, target, @name, @level, errors) =>
 		@priority = target.priority
 		@buildfunctions = target.buildfunctions
 		@mkdirs = target._mkdirs
@@ -101,7 +123,7 @@ class DepNode
 		@type = 'virtual' if #@outs == 0
 		@built = false
 
-		resolve = (name) -> @dag\resolvedeps patsubst @name, target.pattern, name
+		resolve = (name) -> @dag\resolvedeps (patsubst @name, target.pattern, name), level + 1, errors
 		after = flatten foreach target.needtargets, resolve
 		deps = flatten foreach target.infiles, resolve
 		if #target.depfunctions!=0
@@ -149,7 +171,7 @@ class DepNode
 
 		return false if @built or #@buildfunctions == 0
 		return false unless force or @shouldbuild!
-		print "#{@type == 'virtual' and "Running" or "Building"} #{@name}" unless quiet
+		print "#{@type == 'virtual' and "Running" or "Building"} #{@name} [level #{@level}]" unless quiet
 		@actuallybuild!
 		true
 

out/moonbuild.lua

@@ -1,5 +1,3 @@
-do
-
 do
 local _ENV = _ENV
 package.preload[ "moonbuild._" ] = function( ... ) local arg = _G.arg;
@@ -1750,7 +1748,7 @@ do
       if self.nodes[name] then
         return 
       end
-      local elected = self:resolvedeps(name)
+      local elected = self:topresolvedeps(name)
       self.nodes[name] = elected
       local _list_0 = (transclosure(elected, 'deps'))
       for _index_0 = 1, #_list_0 do
@@ -1760,10 +1758,42 @@ do
       end
       elected.deps = nil
     end,
-    resolvedeps = function(self, name)
+    topresolvedeps = function(self, name)
+      local errors = { }
+      local ok, rst = pcall(function()
+        return self:resolvedeps(name, nil, errors)
+      end)
+      if ok then
+        return rst
+      else
+        local msg = {
+          "Failed to resolve target \'" .. tostring(name) .. "\'\n"
+        }
+        for _index_0 = 1, #errors do
+          local e = errors[_index_0]
+          if e.err:match('^moonbuild') then
+            e.err = e.err:match(': (.+)$')
+          end
+        end
+        for i = #errors, 1, -1 do
+          local e = errors[i]
+          insert(msg, tostring(string.rep('| ', e.level - 1)) .. "+-[" .. tostring(e.name) .. "] level " .. tostring(e.level) .. ": " .. tostring(e.err))
+        end
+        insert(msg, '')
+        return error(table.concat(msg, '\n'))
+      end
+    end,
+    resolvedeps = function(self, name, level, errors)
+      if level == nil then
+        level = 1
+      end
+      if errors == nil then
+        errors = { }
+      end
       do
         local node = self.nodes[name]
         if node then
+          print("deps(" .. tostring(name) .. ") = " .. tostring(node.name or '[noname]'))
           return node, { }
         end
       end
@@ -1777,7 +1807,7 @@ do
         return {
           a = {
             pcall(function()
-              return DepNode(self, candidate, name)
+              return DepNode(self, candidate, name, level, errors)
             end)
           }
         }
@@ -1788,7 +1818,16 @@ do
         return node.a[2]
       end)
       sort(resolved, nodepriority)
-      return resolved[1] or error("Cannot resolve target " .. tostring(name) .. ": " .. tostring(#candidates) .. " candidates, " .. tostring(#resolved) .. " resolved")
+      if not (resolved[1]) then
+        local err = "Cannot resolve target " .. tostring(name) .. ": " .. tostring(#candidates) .. " candidates, " .. tostring(#resolved) .. " resolved"
+        table.insert(errors, {
+          name = name,
+          level = level,
+          err = err
+        })
+        error(err)
+      end
+      return resolved[1]
     end,
     buildablenodes = function(self)
       local _accum_0 = { }
@@ -1917,7 +1956,7 @@ do
         return false
       end
       if not (quiet) then
-        print(tostring(self.type == 'virtual' and "Running" or "Building") .. " " .. tostring(self.name))
+        print(tostring(self.type == 'virtual' and "Running" or "Building") .. " " .. tostring(self.name) .. " [level " .. tostring(self.level) .. "]")
       end
       self:actuallybuild()
       return true
@@ -1999,8 +2038,8 @@ do
   }
   _base_0.__index = _base_0
   _class_0 = setmetatable({
-    __init = function(self, dag, target, name)
-      self.dag, self.name = dag, name
+    __init = function(self, dag, target, name, level, errors)
+      self.dag, self.name, self.level = dag, name, level
       self.priority = target.priority
       self.buildfunctions = target.buildfunctions
       self.mkdirs = target._mkdirs
@@ -2015,7 +2054,7 @@ do
       self.built = false
       local resolve
       resolve = function(name)
-        return self.dag:resolvedeps(patsubst(self.name, target.pattern, name))
+        return self.dag:resolvedeps((patsubst(self.name, target.pattern, name)), level + 1, errors)
       end
       local after = flatten(foreach(target.needtargets, resolve))
       local deps = flatten(foreach(target.infiles, resolve))
@@ -2750,8 +2789,6 @@ end
 end
 end
 
-end
-
 local loadfile
 loadfile = require('moonscript.base').loadfile
 local Context = require('moonbuild.context')