Detect diamond

tool/gedoc/Makefile

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+OPT=-finalize
+DIR=F_code
+DIR=W_code
+ise:
+	ec -freeze -c_compile -config src/system.ecf
+
+clean_ise:
+	ec -clean -config src/system.ecf
+
+
+OPT= --gc=no --capability=concurrency=none  #  --finalize --no-benchmark
+gobo:  # does not work: https://github.com/gobo-eiffel/gobo/issues/71
+	gec $(OPT) src/system.ecf
+
+fmt=implicit_converts
+fmt=attr_rename
+
+demo_ecf = ./test/tool/system.ecf
+demo_ecf = src/system.ecf
+demo:
+	gedoc --format=$(fmt) $(demo_ecf) > inherited_fields.path
+
+clean:
+	$(RM) -fr *.c *.o *.make *.h *.sh EIFGENs/

tool/gedoc/README.md

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+# New tool: Detect attribute (i.e field) renaming in diamond inheritance
+
+## Background:
+
+We discovered a semantic problem in Eiffel's attribute renaming mechanism when applied to the diamond problem of multiple inheritance,
+and confirmed it by showing divergent and problematic outputs for the same example code in three major different
+Eiffel compilers.
+
+Please check the detail here:
+[https://github.com/joortcom/eiffel\_rename](https://github.com/joortcom/eiffel_rename)
+
+and doc here: [https://github.com/joortcom/eiffel\_rename/blob/main/eiffel\_rename.pdf](https://github.com/joortcom/eiffel_rename/blob/main/eiffel_rename.pdf)
+
+### Executive summary:
+For the time being (before Eiffel's attribute renaming semantics is settled & fixed
+-- which most likely will be a *breaking* change of existing code),
+please avoid attribute renaming in any diamond inheritance.
+
+### A bit more detail:
+
+In [ECMA-367 (specification for the Eiffel programming language)](https://www.ecma-international.org/wp-content/uploads/ECMA-367_2nd_edition_june_2006.pdf)
+
+1) by 8.16.2 “Any two of these features inherited under a different name yield two features of D”:
+which means replicated (i.e. separated copies) features (attributes in particular) in the diamond bottom class D;
+
+2) while by 8.6.16 “Semantics: Renaming principle”: “Renaming does not affect the semantics of an inherited feature”:
+which is not a very precise description.
+
+So in the actual compiler implementations:
+
+* ISE compiler (tested the lastest version 23.09):
+  * In workbench mode: implemented (2) 8.6.16 as reference identity semantics: i.e renamed attributes are all reference equal!
+  * In finalized mode: skipped (2) 8.6.16, only implemented (1) 8.16.2: i.e renamed attributes are replicated.
+* GOBO compiler (tested the lastest version 22.01):
+  * skipped (2) 8.6.16, only implemented (1) 8.16.2: i.e renamed attributes are replicated.
+* SmartEiffel compiler (tested the last known ECMA compilant version 1.1):
+  * skipped (2) 8.6.16, only implemented (1) 8.16.2: i.e renamed attributes are replicated.
+
+
+## Goal:
+
+Help Eiffel programmers to detect and avoid attribute renaming in a diamond inheritance.
+
+## Usage:
+
+Tool is here: [detect\_diamond.py](https://github.com/joortcom/gobo/blob/detect_diamond/tool/gedoc/detect_diamond.py)
+
+```
+$GOBO/tool/gedoc/detect_diamond.py <single_file.ecf> or <dir (which will be recursively scanned for all the .ecf files)>
+```
+
+## Demo:
+
+First, from *THIS branch* build all the GOBO tools, esp `gec` and `gedoc` as you usually do.
+
+Then, run the `detect_diamond.py` tool
+
+```
+$ cd $GOBO/tool/gedoc/example/rename
+$ $GOBO/tool/gedoc/detect_diamond.py app.ecf
+check:  app.ecf
+======================================== app.ecf total fields:  966
+diamond found, full paths:  PERSON.addr  =>  RESEARCH_ASSISTANT.{student_addr, faculty_addr, addr}
+   student_addr {('PERSON.addr', 'STUDENT.addr', 'RESEARCH_ASSISTANT.student_addr')}
+   faculty_addr {('PERSON.addr', 'FACULTY.addr', 'RESEARCH_ASSISTANT.faculty_addr')}
+   addr {('PERSON.addr', 'RESEARCH_ASSISTANT.addr')}
+new_fields: RESEARCH_ASSISTANT.{student_addr, faculty_addr, addr}
+diamond core:  PERSON.addr  =>  RESEARCH_ASSISTANT.{student_addr, faculty_addr, addr}
+   student_addr [('PERSON.addr', 'STUDENT.addr', 'RESEARCH_ASSISTANT.student_addr')]
+   faculty_addr [('PERSON.addr', 'FACULTY.addr', 'RESEARCH_ASSISTANT.faculty_addr')]
+   addr [('PERSON.addr', 'RESEARCH_ASSISTANT.addr')]
+```
+
+And, run the compiler to see different outputs for the *same* code:
+
+* ISE compiler implements the reference identity semantics in workbench mode
+* ISE compiler implements the replica semantics in finalize mode
+* GOGO compiler implements the replica semantics
+
+```
+$ cd $GOBO/tool/gedoc/example/rename  # the same dir as above
+$ make ise
+============================================================================================
+NOTE: ISE compiler implements the troublesome reference identity semantics in workbench mode
+============================================================================================
+
+ec -clean  -full  app.e
+
+...
+
+C compilation completed
+chmod +x ./app
+mv app app_w
+============================================================================================
+./app_w > ise_w.out
+cat       ise_w.out
+ResAssis has 3 addresses: <home, home, home>
+PERSON  size: 32
+STUDENT size: 32
+FACULTY size: 32
+RESEARCH_ASSISTANT size: 48
+ResAssis do_benchwork in the: home
+ResAssis take_rest in the: home
+-- print_student|faculty_addr_direct_field
+ResAssis as STUDENT.addr: home
+ResAssis as FACULTY.addr: home
+-- print_student|faculty_addr_via_accessor
+ResAssis as STUDENT.addr: home
+ResAssis as FACULTY.addr: home
+-- check reference identity
+ra.addr  = ra.faculty_addr
+ra.addr  = ra.student_addr
+ra.student_addr  = ra.faculty_addr
+-- test some assignment: suppose ra moved both lab2 and dorm2
+ResAssis has 3 addresses: <lab2, lab2, lab2>
+ResAssis has 3 addresses: <dorm2, dorm2, dorm2>
+============================== Press enter to continue ============================== 
+
+
+============================================================================================
+***NOTE***: ISE compiler implements the replica semantics in finalize mode
+============================================================================================
+ec -clean  -finalize -full  app.e
+C compilation completed
+chmod +x ./app
+mv app app_f
+============================================================================================
+./app_f > ise_f.out
+cat       ise_f.out
+ResAssis has 3 addresses: <home, dorm, lab>
+PERSON  size: 32
+STUDENT size: 32
+FACULTY size: 32
+RESEARCH_ASSISTANT size: 48
+ResAssis do_benchwork in the: home
+ResAssis take_rest in the: home
+-- print_student|faculty_addr_direct_field
+ResAssis as STUDENT.addr: home
+ResAssis as FACULTY.addr: home
+-- print_student|faculty_addr_via_accessor
+ResAssis as STUDENT.addr: home
+ResAssis as FACULTY.addr: home
+-- check reference identity
+ra.addr != ra.faculty_addr
+ra.addr != ra.student_addr
+ra.student_addr != ra.faculty_addr
+-- test some assignment: suppose ra moved both lab2 and dorm2
+ResAssis has 3 addresses: <lab2, dorm, lab>
+ResAssis has 3 addresses: <dorm2, dorm, lab>
+
+$ make gobo
+<your gobo dir>/bin/gec app.ecf
+...
+============================================================================================
+./app > gobo.out
+cat     gobo.out
+ResAssis has 3 addresses: <home, dorm, lab>
+PERSON  size: 32
+STUDENT size: 32
+FACULTY size: 32
+RESEARCH_ASSISTANT size: 48
+ResAssis do_benchwork in the: home
+ResAssis take_rest in the: home
+-- print_student|faculty_addr_direct_field
+ResAssis as STUDENT.addr: home
+ResAssis as FACULTY.addr: home
+-- print_student|faculty_addr_via_accessor
+ResAssis as STUDENT.addr: home
+ResAssis as FACULTY.addr: home
+-- check reference identity
+ra.addr != ra.faculty_addr
+ra.addr != ra.student_addr
+ra.student_addr != ra.faculty_addr
+-- test some assignment: suppose ra moved both lab2 and dorm2
+ResAssis has 3 addresses: <lab2, dorm, lab>
+ResAssis has 3 addresses: <dorm2, dorm, lab>
+
+```
+
+## Diamonds found in real code:
+
+In ISE 23.09:
+
+```
+$ cd $ISE_EIFFEL/examples/docking/simple/
+$ $GOBO/tool/gedoc/detect_diamond.py .
+check:  .
+
+...
+
+======================================== ./docking_simple.ecf total fields:  15892
+diamond found, full paths:  EV_PIXMAPABLE.implementation  =>  SD_PLACE_HOLDER_ZONE.{implementation, implementation_upper_zone}
+   implementation {('EV_PIXMAPABLE.implementation', 'EV_CONTAINER.implementation', 'EV_CELL.implementation', 'SD_DOCKING_ZONE.implementation', 'SD_PLACE_HOLDER_ZONE.implementation')}
+   implementation_upper_zone {('EV_PIXMAPABLE.implementation', 'EV_CONTAINER.implementation', 'SD_UPPER_ZONE.implementation_upper_zone', 'SD_PLACE_HOLDER_ZONE.implementation_upper_zone')}
+new_fields: SD_PLACE_HOLDER_ZONE.{implementation, implementation_upper_zone}
+diamond core:  EV_CONTAINER.implementation  =>  SD_PLACE_HOLDER_ZONE.{implementation, implementation_upper_zone}
+   implementation [('EV_CONTAINER.implementation', 'EV_CELL.implementation', 'SD_DOCKING_ZONE.implementation', 'SD_PLACE_HOLDER_ZONE.implementation')]
+   implementation_upper_zone [('EV_CONTAINER.implementation', 'SD_UPPER_ZONE.implementation_upper_zone', 'SD_PLACE_HOLDER_ZONE.implementation_upper_zone')]
+```
+
+And if you run the workbench build, it will run normally:
+```
+/Eiffel_23.09/examples/docking/simple$ ./EIFGENs/docking_simple/W_code/docking_simple
+```
+
+but if you run the finalized build, it will fail (Ubuntu 22.04.3 LTS, x86_64), it will fail:
+```
+/Eiffel_23.09/examples/docking/simple$ ./EIFGENs/docking_simple/F_code/docking_simple
+
+docking_simple: system execution failed.
+Following is the set of recorded exceptions:
+
+******************************** Thread exception *****************************
+In thread           Root thread            0x0 (thread id)
+*******************************************************************************
+-------------------------------------------------------------------------------
+Class / Object      Routine                Nature of exception           Effect
+-------------------------------------------------------------------------------
+VISION2_APPLICATION root's creation        Segmentation fault:
+<00007FC1A8207558>                         Operating system signal.      Exit
+-------------------------------------------------------------------------------
+VISION2_APPLICATION root's creation
+<00007FC1A8207558>                         Routine failure.              Exit
+-------------------------------------------------------------------------------
+```
+
+## TODO & Feedbacks:
+
+Right now this tool is still a prototype, but good enough to detect problems in the real code.
+Eric Bezault has kindly agreed to properly integrate into `gedoc` in the near future
+[https://github.com/gobo-eiffel/gobo/pull/77#issuecomment-1986971690](https://github.com/gobo-eiffel/gobo/pull/77#issuecomment-1986971690).
+Many thanks to Eric for his help in developing this prototype!
+
+But everybody is busy, if you are good at (GOBO) Eiffel and can help, please
+[follow the suggestions by Eric](https://github.com/gobo-eiffel/gobo/pull/77#issuecomment-1986805714)
+and create a new PR for Eric to review.
+
+If you have questions, comments, or just want to inform us the problems found in your own code
+by using this tool, please log an issue *in the other repo* (*NOT* here in this GOBO repo)
+[https://github.com/joortcom/eiffel\_rename](https://github.com/joortcom/eiffel_rename),
+So everything regarding Eiffel `rename` (not *GOBO*) can be easily tracked *there*.
+
+Thanks!
+