Re: Bug#385720: m4: INTERNAL ERROR: recursive push_string (fwd)

[Eric Blake]

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[adding autoconf to cc]

According to Santiago Vila on 9/3/2006 6:55 AM:
> Andreas Schultz <address@hidden> writes:
> 
>   m4 crashes with "m4: INTERNAL ERROR: recursive push_string"
> 
> Later, he adds:
> 
>   It seems that the problem is reproducible with every automake project
>   that has a) AC_OUTPUT on the last line in configure.ac and b) no
>   terminating newline on that line. Adding a newline will make the
>   problem disappear.
> 
> and in fact, I can reproduce it using GNU hello 2.1.1 by removing the
> last two lines of configure.ac, removing also the newline from the
> AC_OUTPUT final line, and then trying "./configure; make configure".
> 
> This is with m4 1.4.6, and it did not happen with m4 1.4.4.

Thanks for a useful bug report.  I will spend time narrowing down what is
causing this regression, and hope to get m4 1.4.7 out within a month,
after I see if any other bugs are reported.  But be advised that POSIX
only requires m4 to process text files, and a file that does not end in a
newline is not a text file (unless it is empty), so the bug is only
triggered when you are violating POSIX.  On the other hand, as a quality
of implementation issue, I totally agree that this is not good practice
for GNU software.  In the meantime, perhaps Autoconf should document that
all autom4te input files should always end in newline.

- --
Life is short - so eat dessert first!

Eric Blake             address@hidden
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