Tcl Source Code

More details can be found here: https://stackoverflow.com/questions/78134384/how-to-get-line-number-and-filename-locations-for-errors-that-occur-while-using

To summarize, though, when an error occurs while using interp eval, the error outputs the location of the interp eval call, rather than the location of the actual erroneous code being evaluated.

This may make sense from the perspective of the caller of interp eval.
However, it creates difficulties in the context of implementing something like a plugin system that interp evals scripts, as the writers of the plugin scripts would receive less useful information than might be desired.

Some example code and their outputs:

Example A:
#!/bin/sh    
# This line continues for Tcl, but is a single line for 'sh' \    
exec tclsh "$0" ${1+"$@"}    
    
::safe::interpCreate i    
i eval {expr {"a" + 1}}

Example A Output:

./example.tcl 
can't use non-numeric string as operand of "+"
    invoked from within
"expr {"a" + 1}"
    invoked from within
"i eval {expr {"a" + 1}}"
    (file "./example.tcl" line 6)

Example B:
#!/bin/sh    
# This line continues for Tcl, but is a single line for 'sh' \    
exec tclsh "$0" ${1+"$@"}    
    
::safe::interpCreate i    
i eval [list expr {"a" + 1}]

Example B output:
./example.tcl 
can't use non-numeric string as operand of "+"
    while executing
"expr {"a" + 1}"
    invoked from within
"i eval [list expr {"a" + 1}]"
    (file "./example.tcl" line 6)

Example C:
#!/bin/sh    
# This line continues for Tcl, but is a single line for 'sh' \    
exec tclsh "$0" ${1+"$@"}    
    
::safe::interpCreate i    
i eval [list expr [list "a" + 1]]

Example C output:
./example.tcl 
invalid bareword "a"
in expression "a + 1";
should be "$a" or "{a}" or "a(...)" or ...
    (parsing expression "a + 1")
    invoked from within
"expr {a + 1}"
    invoked from within
"i eval [list expr [list "a" + 1]]"
    (file "./example.tcl" line 6)

Fixed now in [5cd276dee1c2a46f], tests pass, thus close.

******** 04128CA8 ==> 014058B0 : 1 - can't use package in a safe interpreter: no Safepkg1_SafeInit procedure
    while executing
"load {} Safepkg1 x"
******** 014058B0 ==> 04128CA8 : 59 - load of binary library for package Safepkg1 failed: can't use package in a safe interpreter: no Safepkg1_SafeInit procedure
******** 04128CA8 ==> 014058B0 : 1 - load of binary library for package Safepkg1 failed: can't use package in a safe interpreter: no Safepkg1_SafeInit procedure
    ("interp eval" body line 59)
    invoked from within
"load {} Safepkg1 x"

Since no objections, merged now in [f1d2397c7c640072]. Ticket closed as resolved.

Already answered on stackoverflow, however hereafter noticed that sometimes it may be indeed interesting, thus here is a fix [497e526e670a9faf] (done in minimalistic way)...

Reviews are welcome. If no objections follow I'll merge it at some point later.