Re: Incorrect LINENO with exported nested functions with loops

[L A Walsh]

On 2021/10/05 16:25, Tom Coleman wrote
Repeat-By:
        Below is a sample script to replicate the bug in LINENO.
  
---
1st prob: scrip doesn't work as is.
 /tmp/lnno
/tmp/lnno: line 23: syntax error near unexpected token `done'
/tmp/lnno: line 23: ` done'
----
added the line numbers indenting and uncommenting the 2nd for loop to 
prevent the above syntax error:

01 #!/bin/bash
02 # vim=:SetNumberAndWidth
03 setx() { trap unsetx EXIT; set -x; } ; unsetx() { set +x;}
04 export 
PS4='>${BASH_SOURCE:+${BASH_SOURCE/$HOME/\~}}#${LINENO}${FUNCNAME:+(${FUNCNAME})}> 
'
05 setup() {
06   DO_BACKUP() {
07     for d in 1 2 3; do
08       break
09     done
10   }
11   export -f DO_BACKUP
12 }
13 run() {
14  for i in 1; do
15    #for j in 1; do  # Uncomment this 'j' loop instead of the next and 
LINENO is correct
16    for ((j=1; j<=2; j++)); do  # Uncomment this 'j' loop and LINENO 
is incorrect
17        true
18    done
19  done
20 }
21 setx
22 setup
23 run
24
25 # vim  ts=2 sw=2

        The LINENO variable for the 'i' loop which is printed out by the
PS4 is incorrect when that DO_BACKUP function is exported, and the second
'j' loop is uncommented.
-----like this, right?:
 /tmp/lnno
/tmp/lnno#22> setup
/tmp/lnno#11(setup)> export -f DO_BACKUP
/tmp/lnno#23> run
/tmp/lnno#25(run)> for i in 1
/tmp/lnno#16(run)> (( j=1 ))
/tmp/lnno#16(run)> (( j<=2 ))
/tmp/lnno#17(run)> true
/tmp/lnno#16(run)> (( j++ ))
/tmp/lnno#16(run)> (( j<=2 ))
/tmp/lnno#17(run)> true
/tmp/lnno#16(run)> (( j++ ))
/tmp/lnno#16(run)> (( j<=2 ))
/tmp/lnno#1> unsetx
/tmp/lnno#3(unsetx)> set +x



 If you instead uncomment the first 'j' loop, the
LINENO variables are correct. If DO_BACKUP does not have a loop inside it, the 
LINENO variables are all correct.
  
----
   So you are saying that using the 1st j loop instead of the 2nd,
then whether or not "DO_BACKUP" has a loop inside, LINENO is correct?
So that is what one would expect, right?.

   So the main problem above is the line after
">/tmp/lnno#23 run", where the "for i in 1" is listed as being on
">/tmp/lnno#25"  #(line 25)?

And if DO_BACKUP is not exported, then all the line numbers are
correct, like:
 /tmp/lnno
/tmp/lnno#23> setup
/tmp/lnno#24> run
/tmp/lnno#14(run)> for i in 1
/tmp/lnno#15(run)> for j in 1
/tmp/lnno#16(run)> DO_BACKUP
/tmp/lnno#7(DO_BACKUP)> for d in 1 2 3
/tmp/lnno#8(DO_BACKUP)> break
/tmp/lnno#18(run)> true
/tmp/lnno#1> unsetx
/tmp/lnno#3(unsetx)> set +x


Yeah, that's interesting, have you tried the latest version
of bash to see if it does the same thing?  I still need to compile it.

If you export functions, they can do weird things with
numbering.

Like at your bash prompt, try:


imafunc() { echo $LINENO; }; export -f imafunc
echo $LINENO; imafunc; echo $LINENO






#!/bin/bash
export PS4='+L$LINENO + '
setup() {
DO_BACKUP() {
  for d in 1 2 3; do
    break
  done
}
export -f DO_BACKUP
}
run() {
    for i in 1; do
        #for j in 1; do  # Uncomment this 'j' loop instead of the next and
LINENO is correct
        #for ((j=1; j<=2; j++)); do  # Uncomment this 'j' loop and LINENO
is incorrect
            true
        done
    done
}
set -x
setup
run

########

Example output with first 'j' loop uncommented:

$ bash run.sh
+L20 + setup
+L9 + export -f DO_BACKUP
+L21 + run
+L12 + for i in 1
+L13 + for j in 1
+L15 + true

Example output with the second 'j' loop uncommented:

$ bash run.sh
+L20 + setup
+L9 + export -f DO_BACKUP
+L21 + run
+L5 + for i in 1
+L14 + (( j=1 ))
+L14 + (( j<=1 ))
+L15 + true
+L14 + (( j++ ))
+L14 + (( j<=1 ))


Regards,
Tom Coleman