Segfault with an incomplete s7 source

[mingodad]

When testing s7 with the (incomplete) source file code bellow we get a segfault.

const proc: main is func
  begin
    writeln("hello world");
  end func;

Output:

gdb --args s7 hello-bug.sd7 
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Reading symbols from s7...done.
(gdb) r
Starting program: /home/mingo/dev/c/A_programming-languages/seed7/prg/s7 hello-bug.sd7
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
SEED7 INTERPRETER Version 5.0.11752  Copyright (c) 1990-2020 Thomas Mertes
*** hello-bug.sd7(1):46: ";" expected found "proc"
const proc: main is func
----------^
evaluate unknown const: const is <SYMBOLOBJECT> 93824995462896
*** hello-bug.sd7(1):33: Exception raised
const proc: main is func
----------^
*** hello-bug.sd7(1):46: ";" expected found ":"
const proc: main is func
-----------^
evaluate unknown const: proc is <SYMBOLOBJECT> 93824995462992
*** hello-bug.sd7(1):33: Exception raised
const proc: main is func
-----------^
*** hello-bug.sd7(1):46: ";" expected found "main"
const proc: main is func
----------------^
evaluate unknown const: : is <SYMBOLOBJECT> 93824995463072
*** hello-bug.sd7(1):33: Exception raised
const proc: main is func
----------------^
*** hello-bug.sd7(1):46: ";" expected found "is"
const proc: main is func
-------------------^
evaluate unknown const: main is <SYMBOLOBJECT> 93824995463168
*** hello-bug.sd7(1):33: Exception raised
const proc: main is func
-------------------^
*** hello-bug.sd7(1):46: ";" expected found "func"
const proc: main is func
------------------------^
evaluate unknown const: is is <SYMBOLOBJECT> 93824995463248
*** hello-bug.sd7(1):33: Exception raised
const proc: main is func
------------------------^
*** hello-bug.sd7(2):46: ";" expected found "begin"
  begin
-------^
evaluate unknown const: func is <SYMBOLOBJECT> 93824995463328
*** hello-bug.sd7(2):33: Exception raised
  begin
-------^
*** hello-bug.sd7(3):46: ";" expected found "writeln"
    writeln("hello world");
-----------^
evaluate unknown const: begin is <SYMBOLOBJECT> 93824995463424
*** hello-bug.sd7(3):33: Exception raised
    writeln("hello world");
-----------^
*** hello-bug.sd7(3):48: Undefined type for literal "hello world"
    writeln("hello world");
-------------------------^

Program received signal SIGSEGV, Segmentation fault.
new_nonempty_expression_object (first_element=0x555555869180, list=0x7fffffffd600, typeof_object=<optimized out>)
    at object.c:98
98      created_list->type_of = take_type(typeof_object);
(gdb) bt
#0  new_nonempty_expression_object (first_element=0x555555869180, list=0x7fffffffd600, typeof_object=<optimized out>)
    at object.c:98
#1  0x00005555555f9e7f in read_call_expression (do_match_expr=do_match_expr@entry=false) at expr.c:132
#2  0x00005555555fa129 in read_dot_expression (do_match_expr=do_match_expr@entry=false) at expr.c:236
#3  0x00005555555fa42e in pars_infix_expression (priority=49, do_match_expr=false) at expr.c:353
#4  0x00005555555fce5c in declAny (objects=0x555555868ea0) at analyze.c:337
#5  analyzeProg (sourceFileArgument=sourceFileArgument@entry=0x555555868010, 
    sourceFilePath=sourceFilePath@entry=0x555555868480, options=options@entry=256, 
    libraryDirs=libraryDirs@entry=0x55555583ce10, protFileName=protFileName@entry=0x0, 
    err_info=err_info@entry=0x7fffffffd830) at analyze.c:482
#6  0x00005555555ff58f in analyzeFile (sourceFileArgument=0x555555868010, options=256, libraryDirs=0x55555583ce10, 
    protFileName=0x0, err_info=0x7fffffffd830) at analyze.c:604
#7  0x0000555555567993 in analyze (protFileName=<optimized out>, libraryDirs=<optimized out>, 
    options=<optimized out>, sourceFileArgument=0x555555868010) at analyze.c:631
#8  main (argc=<optimized out>, argv=<optimized out>) at s7.c:414

[ThomasMertes]

I can confirm this error. Seed7 is defined in the library seed7_05.s7i. Without including this library nothing will work. In this regard this is a rather strange test case. On the other hand a segfault should not happen. IIRC I investigated this years ago and found out that it could be avoided by adding a check in a performance critical part of the parser. If I have time I will take another look and there is hopefully a possibility to fix this without hindering performance.

[ThomasMertes]

This has been fixed with release 2021-01-30.