[Bug fortran/101627] New: List-directed read with trailing characters after quotes

[Bug fortran/101627] New: List-directed read with trailing characters after quotes

[hj8758558 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101627

            Bug ID: 101627
           Summary: List-directed read with trailing characters after
                    quotes
           Product: gcc
           Version: 11.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hj8758558 at gmail dot com
  Target Milestone: ---

When reading a string delimited by single quotes, but followed by a non-blank
character, gfortran takes the "err" branch. This is in contrast to ifort,
nagfor, and flang, which read the string within the quotes and ignore the
trailing character(s).

Is gfortran's behavior intended?



$ cat test.f90
program test                               

   character(len=6) :: input_str = "'abc'a"
   character(len=6) :: output_str          

   read (input_str, *, err=77) output_str  

   stop 'No read error'                    

77 continue                                
   stop 'Read error'                       

end program test                           


$ gfortran test.f90 && ./a.out
STOP Read error

[Bug fortran/101627] List-directed read with trailing characters after quotes

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101627

kargl at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kargl at gcc dot gnu.org

--- Comment #1 from kargl at gcc dot gnu.org ---
This might fix the issue, but I don't play in libgfortran very
often.  Tried adding Jerry, but bugzilla did not like his addresses.


diff --git a/libgfortran/io/list_read.c b/libgfortran/io/list_read.c
index 8cc7ddbe8e2..e9a628f234f 100644
--- a/libgfortran/io/list_read.c
+++ b/libgfortran/io/list_read.c
@@ -1189,6 +1189,7 @@ read_character (st_parameter_dt *dtp, int length
__attribute__ ((unused)))

   if ((c = next_char (dtp)) == EOF)
     goto eof;
+
   switch (c)
     {
     CASE_SEPARATORS:
@@ -1233,7 +1234,6 @@ read_character (st_parameter_dt *dtp, int length
__attribute__ ((unused)))
              break;
            }

-         unget_char (dtp, c);
          goto done;

        CASE_SEPARATORS:

[Bug fortran/101627] List-directed read with trailing characters after quotes

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101627

kargl at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2021-07-29
           Priority|P3                          |P4
     Ever confirmed|0                           |1

--- Comment #2 from kargl at gcc dot gnu.org ---
Here a correct patch, which has been regression tested.


diff --git a/libgfortran/io/list_read.c b/libgfortran/io/list_read.c
index 8cc7ddbe8e2..b551f2b9843 100644
--- a/libgfortran/io/list_read.c
+++ b/libgfortran/io/list_read.c
@@ -1258,7 +1258,7 @@ read_character (st_parameter_dt *dtp, int length
__attribute__ ((unused)))
  done:
   c = next_char (dtp);
  done_eof:
-  if (is_separator (c) || c == EOF)
+  if (quote == '"' || quote == '\'' || is_separator (c) || c == EOF)
     {
       unget_char (dtp, c);
       eat_separator (dtp);