Improved error library by refactorying the sync as two way propagation.

Now one can setup error handler propagation in one way, or two way (sync).
The "reset" applies in both way, even if this is a one way propagation to fit current existing usage.
Added optional id for the error handlers.
Feature renaming according to design changes.
Added related autotest cases.

library/utility/general/error/package.iron

@@ -5,11 +5,13 @@ project
 	error = "error.ecf"
 
 note
---	title: 
+	title: Error framework
---	description: 
+	description: "[
---	tags: 
+		Errors and associated handler, to manage errors and also provides a way to synchronize one or many error handlers. 
---	license: 
+		This is convenient to propagate error from a layer to another without adding unwanted dependencies.
---	copyright: 
+	tags: error
---	link[doc]: "Documentation" http:// 
+	license: Eiffel Forum License v2
+	copyright: Jocelyn Fiat, Eiffel Software and others.
+	link[license]: http://www.eiffel.com/licensing/forum.txt
 
 end

library/utility/general/error/src/error_custom.e

@@ -16,13 +16,13 @@ create
 
 feature {NONE} -- Initialization
 
-	make (a_code: INTEGER; a_name: like name; a_message: detachable like message)
+	make (a_code: INTEGER; a_name: like name; a_message: detachable READABLE_STRING_GENERAL)
 			-- Initialize `Current'.
 		do
 			code := a_code
 			name := a_name
 			if a_message /= Void then
-				message := a_message
+				message := a_message.as_string_32
 			else
 				message := {STRING_32} "Error: " + a_name + " (code=" + a_code.out + ")"
 			end
@@ -45,7 +45,7 @@ feature -- Visitor
 		end
 
 note
-	copyright: "2011-2012, Eiffel Software and others"
+	copyright: "2011-2016, Jocelyn Fiat, Eiffel Software and others"
 	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
 	source: "[
 			Eiffel Software

library/utility/general/error/src/error_handler.e

@@ -1,5 +1,8 @@
 note
-	description : "Objects that handle error..."
+	description : "[
+			Error handler or receiver.
+
+		]"
 	legal: "See notice at end of class."
 	status: "See notice at end of class."
 	date: "$Date: 2015-10-10 00:55:41 +0200 (sam., 10 oct. 2015) $"
@@ -14,7 +17,8 @@ inherit
 	DEBUG_OUTPUT
 
 create
-	make
+	make,
+	make_with_id
 
 feature {NONE} -- Initialization
 
@@ -25,8 +29,22 @@ feature {NONE} -- Initialization
 			create error_added_actions
 		end
 
+	make_with_id (a_id: READABLE_STRING_8)
+			-- Build `Current' with optional id `a_id'.
+		do
+			make
+			if a_id = Void then
+				id := Void
+			else
+				create id.make_from_string (a_id)
+			end
+		end
+
 feature -- Access
 
+	id: detachable IMMUTABLE_STRING_8
+			-- Optional identifier for Current handler.
+
 	primary_error_code: INTEGER
 			-- Code of first error in `errors'
 		require
@@ -49,6 +67,19 @@ feature -- Status
 			Result := errors.count
 		end
 
+	is_synchronizing_with (other: ERROR_HANDLER): BOOLEAN
+			-- Is Current synchronizing with `other'?
+			-- i.e 2 way propagation.
+		do
+			Result := is_propagating_to (other) and other.is_propagating_to (Current)
+		end
+
+	is_propagating_to (other: ERROR_HANDLER): BOOLEAN
+			-- Is Current propagating error to `other'?
+		do
+			Result := attached propagations as lst and then lst.has (other)
+		end
+
 feature {ERROR_HANDLER, ERROR_VISITOR} -- Restricted access
 
 	errors: LIST [ERROR]
@@ -64,6 +95,25 @@ feature -- Status report
 			else
 				Result := "no error"
 			end
+			if attached id as l_id then
+				Result.prepend ("[" + l_id + "] ")
+			end
+			if attached propagations as lst then
+				check not_empty: not lst.is_empty end
+				Result.append_character ('(')
+				Result.append (" -> ")
+				Result.append_integer (lst.count)
+				Result.append_character (':')
+				across
+					lst as ic
+				loop
+					if attached ic.item.id as l_id then
+						Result.append_character (' ')
+						Result.append (l_id)
+					end
+				end
+				Result.append_character (')')
+			end
 		end
 
 feature -- Events
@@ -77,134 +127,263 @@ feature -- Synchronization
 			-- Add synchronization between `h' and `Current'	
 			--| the same handler can be added more than once
 			--| it will be synchronized only once
-		local
-			lst: like synchronized_handlers
 		do
-			lst := synchronized_handlers
+			add_propagation (h)
-			if lst = Void then
+			h.add_propagation (Current)
-				create {ARRAYED_LIST [ERROR_HANDLER]} lst.make (0)
-				lst.compare_references
-				synchronized_handlers := lst
-			end
-			if lst.has (h) then
-				check attached h.synchronized_handlers as h_lst and then h_lst.has (Current) end
-			else
-				lst.extend (h)
-				h.add_synchronization (Current)
-			end
 		end
 
 	remove_synchronization (h: ERROR_HANDLER)
 			-- Remove synchronization between `h' and `Current'
 		do
-			if attached synchronized_handlers as lst and then not lst.is_empty then
+			remove_propagation (h)
-				synchronized_handlers := Void
+			h.remove_propagation (Current)
+		end
+
+feature -- One way synchronization: propagation
+
+	add_propagation (h: ERROR_HANDLER)
+			-- Add propagation from `Current' to `h'.
+			--| the same handler can be added more than once
+			--| it will be synchronized only once
+		local
+			lst: like propagations
+		do
+			h.register_propagator (Current)
+			lst := propagations
+			if lst = Void then
+				create {ARRAYED_LIST [ERROR_HANDLER]} lst.make (0)
+				lst.compare_references
+				propagations := lst
+			end
+			if not lst.has (h) then
+				lst.extend (h)
+			end
+		end
+
+	remove_propagation (h: ERROR_HANDLER)
+			-- Remove propagation from `Current' to `h'.
+		do
+			if attached propagations as lst and then not lst.is_empty then
 				lst.prune_all (h)
-
-				h.remove_synchronization (Current)
-
-				synchronized_handlers := lst
 				if lst.is_empty then
-					synchronized_handlers := Void
+					propagations := Void
 				end
 			end
+			h.unregister_propagator (Current)
 		end
 
 feature {ERROR_HANDLER} -- Synchronization implementation
 
-	synchronized_handlers: detachable LIST [ERROR_HANDLER]
+	is_associated_with (h: ERROR_HANDLER): BOOLEAN
-			-- Synchronized handlers
-
-	synchronize_error_from (e: ERROR; h_lst: LIST [ERROR_HANDLER])
-			-- Called by error_handler during synchronization process
-			-- if `synchronized_handlers' is Void, this means Current is synchronizing
-			-- this is to prevent infinite cycle iteration
-		require
-			not h_lst.has (Current)
 		do
-			h_lst.extend (Current)
+			if attached propagators as lst then
-
+				Result := lst.has (h)
-			if attached synchronized_handlers as lst then
-				synchronized_handlers := Void
-				add_error (e)
-				across
-					lst as c
-				loop
-					if not h_lst.has (c.item) then
-						c.item.synchronize_error_from (e, h_lst)
-					end
-				end
-				synchronized_handlers := lst
-			else
-				-- In synchronization
 			end
 		end
 
-	synchronize_reset_from (h_lst: LIST [ERROR_HANDLER])
+	register_propagator (h: ERROR_HANDLER)
-			-- Called by error_handler during synchronization process
+		local
-			-- if `synchronized_handlers' is Void, this means Current is synchronizing
+			lst: like propagators
-			-- this is to prevent infinite cycle iteration
+		do
+			lst := propagators
+			if lst = Void then
+				create {ARRAYED_LIST [ERROR_HANDLER]} lst.make (1)
+				propagators := lst
+			end
+			if not lst.has (h) then
+				lst.extend (h)
+			end
+		end
+
+	unregister_propagator (h: ERROR_HANDLER)
+		local
+			lst: like propagators
+		do
+			lst := propagators
+			if lst /= Void then
+				lst.prune_all (h)
+				if lst.is_empty then
+					propagators := Void
+				end
+			end
+		end
+
+	propagators: detachable LIST [ERROR_HANDLER]
+			-- Handlers propagating to Current.
+			-- Needed for `reset'.
+
+	propagations: detachable LIST [ERROR_HANDLER]
+			-- Handlers receiving the propagation.
+
+	propagate_error_addition (e: ERROR; h_lst: LIST [ERROR_HANDLER])
+			-- Called by error_handler during synchronization process.
+			-- To prevent infinite cycle, if Currently synchronizing, the `propagations' is Void.
 		require
 			not h_lst.has (Current)
+		local
+			lst: like propagations
 		do
 			h_lst.extend (Current)
-			if attached synchronized_handlers as lst then
+			lst := propagations
-				synchronized_handlers := Void
+			propagations := Void
-				reset
+			add_error (e)
+
+			if lst /= Void then
 				across
 					lst as c
 				loop
 					if not h_lst.has (c.item) then
-						c.item.synchronize_reset_from (h_lst)
+						c.item.propagate_error_addition (e, h_lst)
 					end
 				end
-				synchronized_handlers := lst
+				propagations := lst
 			else
-				-- In synchronization				
+					--| propagating
+			end
+		end
+
+	propagate_errors_removal (errs: ITERABLE [ERROR]; h_lst: LIST [ERROR_HANDLER])
+			-- Called by error_handler during synchronization process.
+			-- To prevent infinite cycle, if Currently synchronizing, the `propagations' is Void.
+		require
+			not h_lst.has (Current)
+		local
+			lst: like propagations
+		do
+			h_lst.extend (Current)
+			lst := propagations
+			propagations := Void
+			across
+				errs as ic
+			loop
+					-- Question: should we use remove_error (ic.item) ?
+				errors.prune_all (ic.item)
+			end
+
+			if lst /= Void then
+				across
+					lst as c
+				loop
+					if not h_lst.has (c.item) then
+						c.item.propagate_errors_removal (errs, h_lst)
+					end
+				end
+				propagations := lst
+			else
+					--| propagating				
+			end
+		end
+
+	backpropagate_reset (h_lst: LIST [ERROR_HANDLER])
+			-- Called by error_handler during propagation process.
+			-- To prevent infinite cycle, if Currently synchronizing, the `propagations' is Void.
+		require
+			not h_lst.has (Current)
+		local
+			lst: like propagations
+		do
+			h_lst.extend (Current)
+			lst := propagations
+			propagations := Void
+			reset
+			if lst /= Void then
+				across
+					lst as c
+				loop
+					if not h_lst.has (c.item) then
+							-- Reset c.item, even if this is not a two way synchronization!
+						c.item.backpropagate_reset (h_lst)
+					end
+				end
+				propagations := lst
+			else
+					--| propagating				
 			end
 		end
 
 feature {NONE} -- Event: implementation
 
 	on_error_added (e: ERROR)
-			-- Error `e' was just added
+			-- Error `e' was just added.
 		local
-			sync_list: LINKED_LIST [ERROR_HANDLER]
+			sync_list: ARRAYED_LIST [ERROR_HANDLER]
 		do
 			error_added_actions.call ([e])
-			if attached synchronized_handlers as lst then
+			if attached propagations as lst then
-				synchronized_handlers := Void
+				propagations := Void
-				create sync_list.make
+				create sync_list.make (1 + lst.count)
 				sync_list.extend (Current)
 				across
 					lst as c
 				loop
 					if not sync_list.has (c.item) then
-						c.item.synchronize_error_from (e, sync_list)
+						c.item.propagate_error_addition (e, sync_list)
 					end
 				end
-				synchronized_handlers := lst
+				propagations := lst
+			end
+		end
+
+	on_errors_removed (errs: ITERABLE [ERROR])
+			-- Errors `errs' were just removed.
+		local
+			sync_list: ARRAYED_LIST [ERROR_HANDLER]
+			lst: like propagations
+		do
+			lst := propagations
+			if lst /= Void then
+				propagations := Void
+				create sync_list.make (1 + lst.count)
+				sync_list.extend (Current)
+				across
+					lst as c
+				loop
+					if not sync_list.has (c.item) then
+						c.item.propagate_errors_removal (errs, sync_list)
+					end
+				end
+				propagations := lst
 			end
 		end
 
 	on_reset
 			-- `reset' was just called
 		local
-			sync_list: LINKED_LIST [ERROR_HANDLER]
+			sync_list: detachable ARRAYED_LIST [ERROR_HANDLER]
+			lst: detachable LIST [ERROR_HANDLER]
 		do
-			if attached synchronized_handlers as lst then
+			lst := propagators
-				synchronized_handlers := Void
+			if lst /= Void then
-				create sync_list.make
+				create sync_list.make (1 + lst.count)
 				sync_list.extend (Current)
+
+				propagators := Void
 				across
 					lst as c
 				loop
 					if not sync_list.has (c.item) then
-						c.item.synchronize_reset_from (sync_list)
+						c.item.backpropagate_reset (sync_list)
 					end
 				end
-				synchronized_handlers := lst
+				propagators := lst
 			end
+
+--			lst := propagations
+--			propagations := Void
+--			if lst /= Void then
+--				if sync_list = Void then
+--					create sync_list.make (1 + lst.count)
+--					sync_list.extend (Current)
+--				end
+--				across
+--					lst as c
+--				loop
+--					if not sync_list.has (c.item) then
+--						c.item.synchronize_reset_from (sync_list)
+--					end
+--				end
+--				propagations := lst
+--			end
 		end
 
 feature -- Basic operation
@@ -216,7 +395,17 @@ feature -- Basic operation
 			on_error_added (a_error)
 		end
 
-	add_error_details, add_custom_error (a_code: INTEGER; a_name: STRING; a_message: detachable READABLE_STRING_32)
+	remove_error (a_error: ERROR)
+			-- Remove `a_error' from the stack of error.
+			-- And also propagate error removal.
+		do
+			if propagations /= Void then
+				on_errors_removed (<<a_error>>)
+			end
+			errors.prune_all (a_error)
+		end
+
+	add_error_details, add_custom_error (a_code: INTEGER; a_name: STRING; a_message: detachable READABLE_STRING_GENERAL)
 			-- Add custom error to the stack of error
 		local
 			e: ERROR_CUSTOM
@@ -285,11 +474,22 @@ feature -- Element changes
 		end
 
 	reset
-			-- Reset error handler
+			-- Reset Current error handler.
+			-- And also reset recursively error handlers propagating to Current (i.e the propagators).
+		do
+			errors.wipe_out
+			on_reset
+		ensure
+			has_no_error: not has_error
+			count = 0
+		end
+
+	remove_all_errors
+			-- Remove all errors.
 		do
 			if errors.count > 0 then
+				on_errors_removed (errors)
 				errors.wipe_out
-				on_reset
 			end
 		ensure
 			has_no_error: not has_error
@@ -297,22 +497,26 @@ feature -- Element changes
 		end
 
 	destroy
-			-- Destroy Current, and remove any synchronization
+			-- Destroy Current, and remove any propagations (in the two directions).
 		do
 			error_added_actions.wipe_out
-			if attached synchronized_handlers as lst then
+			if attached propagations as lst then
+				propagations := Void
 				across
 					lst as c
 				loop
 					c.item.remove_synchronization (Current)
 				end
 			end
-			synchronized_handlers := Void
 			reset
 		end
 
+invariant
+	propagations_not_empty: attached propagations as lst implies not lst.is_empty
+	propagators_not_empty: attached propagators as lst implies not lst.is_empty
+
 note
-	copyright: "2011-2014, Jocelyn Fiat, Eiffel Software and others"
+	copyright: "2011-2016, Jocelyn Fiat, Eiffel Software and others"
 	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
 	source: "[
 			Eiffel Software

library/utility/general/error/tests/test_error.e

@@ -38,6 +38,30 @@ feature -- Test routines
 
 		end
 
+	test_propagation_2
+		note
+			testing:  "error"
+		local
+			h1, h2: ERROR_HANDLER
+--			cl: CELL [INTEGER]
+		do
+			create h1.make_with_id ("h1")
+			create h2.make_with_id ("h2")
+
+			h1.add_propagation (h2)
+
+			h1.add_custom_error (123, "abc", "abc error occurred")
+			h1.add_custom_error (456, "def", "def error occurred")
+
+			assert ("has 2 errors", h1.count = 2 and h2.count = h1.count)
+
+			h2.add_custom_error (789, "ghi", "error occurred only for h2")
+			assert ("h1 has 2 errors, h2 has 3 errors", h1.count = 2 and h2.count = h1.count + 1)
+
+			h1.remove_all_errors
+			assert ("remove all error from h1, and one remaining on h2", h1.count = 0 and h2.count = 1)
+		end
+
 	test_sync_2
 		note
 			testing:  "error"
@@ -50,7 +74,7 @@ feature -- Test routines
 			h1.add_synchronization (h2)
 
 			h1.add_custom_error (123, "abc", "abc error occurred")
-			h1.add_custom_error (456, "abc", "abc error occurred")
+			h1.add_custom_error (456, "def", "def error occurred")
 
 			assert ("has 2 errors", h1.count = 2 and h2.count = h1.count)
 
@@ -108,6 +132,62 @@ feature -- Test routines
 
 		end
 
+	test_tree_propag
+			--| Testing tree propagation
+			--|
+			--|          |-----> batch ..........
+			--|          |                      :
+			--| db ---> core ---> app ----> ui  :
+			--|  :       :         :        :   :
+			--|  :.......:.........:........:...:.....> logger
+			--|
+		note
+			testing:  "error"
+		local
+			hdb, hcore, happ, hui, hlog, hbat: ERROR_HANDLER
+		do
+			create hdb.make_with_id ("db")
+			create hcore.make_with_id ("core")
+			create happ.make_with_id ("app")
+			create hui.make_with_id ("ui")
+			create hlog.make_with_id ("logger")
+			create hbat.make_with_id ("batch")
+
+			hdb.add_propagation (hcore)
+			hcore.add_propagation (happ)
+			hcore.add_propagation (hbat)
+			happ.add_propagation (hui)
+
+			hdb.add_propagation (hlog)
+			hcore.add_propagation (hlog)
+			happ.add_propagation (hlog)
+			hui.add_propagation (hlog)
+			hbat.add_propagation (hlog)
+
+			hdb.add_custom_error (1, "db", "database connection error")
+			hdb.add_custom_error (2, "db", "database query error")
+			assert ("2 errors", hdb.count = 2 and hcore.count = 2 and happ.count = 2 and hui.count = 2 and hlog.count = 2)
+			hcore.add_custom_error (11, "core", "core error")
+			assert ("3 errors", hdb.count = 2 and hcore.count = 3 and happ.count = 3 and hui.count = 3 and hlog.count = 3)
+			happ.add_custom_error (101, "app", "app issue")
+			assert ("2 errors", hdb.count = 2 and hcore.count = 3 and happ.count = 4 and hui.count = 4 and hlog.count = 4)
+			hui.add_custom_error (1001, "ui", "user interface trouble")
+			assert ("2 errors", hdb.count = 2 and hcore.count = 3 and happ.count = 4 and hui.count = 5 and hlog.count = 5)
+
+			assert ("hbat", hbat.count = 3 and hlog.count = 5)
+			hbat.add_custom_error (10001, "bat", "Batch issue")
+			assert ("2 errors", hdb.count = 2 and hcore.count = 3 and happ.count = 4 and hui.count = 5 and hbat.count = 4 and hlog.count = 6)
+			hbat.remove_all_errors
+			assert ("2 errors", hdb.count = 2 and hcore.count = 3 and happ.count = 4 and hui.count = 5 and hbat.count = 0 and hlog.count = 2)
+
+			hui.remove_all_errors
+			assert ("2 errors", hdb.count = 2 and hcore.count = 3 and happ.count = 4 and hui.count = 0 and hlog.count = 0)
+
+			hdb.reset
+			assert ("no more errors", hdb.count = 0 and hcore.count = 3 and happ.count = 4 and hui.count = 0 and hlog.count = 0)
+
+		end
+
 	test_remove_sync
 		note
 			testing:  "error"
@@ -145,9 +225,9 @@ feature -- Test routines
 			h1, h2, h3: ERROR_HANDLER
 --			cl: CELL [INTEGER]
 		do
-			create h1.make
+			create h1.make_with_id ("h1")
-			create h2.make
+			create h2.make_with_id ("h2")
-			create h3.make
+			create h3.make_with_id ("h3")
 
 			h1.add_synchronization (h2)
 			h2.add_synchronization (h3)

library/utility/general/error/tests/tests-safe.ecf

@@ -1,17 +1,21 @@
 <?xml version="1.0" encoding="ISO-8859-1"?>
-<system xmlns="http://www.eiffel.com/developers/xml/configuration-1-9-0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.eiffel.com/developers/xml/configuration-1-9-0 http://www.eiffel.com/developers/xml/configuration-1-9-0.xsd" name="error_tests" uuid="54F59BB2-AD49-42C7-ABAA-B60765F4F926">
+<system xmlns="http://www.eiffel.com/developers/xml/configuration-1-15-0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.eiffel.com/developers/xml/configuration-1-15-0 http://www.eiffel.com/developers/xml/configuration-1-15-0.xsd" name="error_tests" uuid="54F59BB2-AD49-42C7-ABAA-B60765F4F926">
 	<target name="error_tests">
 		<root class="TEST_ERROR" feature="default_create"/>
 		<file_rule>
 			<exclude>/.git$</exclude>
-			<exclude>/EIFGENs$</exclude>
 			<exclude>/.svn$</exclude>
+			<exclude>/EIFGENs$</exclude>
 		</file_rule>
-		<option warning="true" full_class_checking="true" is_attached_by_default="true" void_safety="all" syntax="transitional">
+		<option warning="true" full_class_checking="true" is_attached_by_default="true" is_obsolete_routine_type="true" void_safety="transitional" syntax="transitional">
-			<assertions precondition="true"/>
+			<assertions precondition="true" postcondition="true" check="true" invariant="true"/>
 		</option>
 		<library name="base" location="$ISE_LIBRARY\library\base\base-safe.ecf"/>
-		<library name="error" location="..\error-safe.ecf" readonly="false"/>
+		<library name="error" location="..\error-safe.ecf" readonly="false">
+			<option>
+				<assertions precondition="true" postcondition="true" check="true" invariant="true" supplier_precondition="true"/>
+			</option>
+		</library>
 		<library name="testing" location="$ISE_LIBRARY\library\testing\testing-safe.ecf"/>
 		<tests name="tests" location=".\"/>
 	</target>