Parameter expansion stopped working in recent ash/dash

[Brian Inglis]

On 2023-02-07 05:07, Andrey Repin via Cygwin wrote:
> Greetings, All!
> 
> In the attached script, that I always run using dash, the expansion is
> supposed to strip leading/trailing spaces from provided parameter.
> 
> The upgrade that took place after which the expansion stopped working is
> 
> libsolv:   - dash-0.5.11.5-1.any -> dash-0.5.12-1.any
> 
> Downgrading to 0.5.11.5 restored the expected behavior.
> I failed to find anything relevant in the dash 0.5.12 patch notes, but perhaps
> community could help?

Good catch Andrey,

Looks like something in dash broke space trimming of any sort: see attached 
script and logs.

I will see what upstream has to say for themselves, or about Cygwin.

[and stop apologizing for your terrible English, it's better than most, and much 
better than most of our Russian, but we are ni kulturni, da? I kept missing out 
on new language classes because teachers got transferred: no Russian at 11, no 
Spanish at 17, or I could be kulturni!] ;^>

-- 
Take care. Thanks, Brian Inglis			Calgary, Alberta, Canada

La perfection est atteinte			Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter	not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer	but when there is no more to cut
			-- Antoine de Saint-Exupéry
-------------- next part --------------
#!/bin/dash -vx

trim() {
  # remove leading whitespace characters
  __trim="${*#${*%%[![:space:]]*}}"
  # remove trailing whitespace characters
  printf "%s" "${__trim%${__trim##*[![:space:]]}}"
}

trim " alpha" | od -t x1a
trim "beta " | od -t x1a
trim "
gamma	" | od -t x1a

trim2() {
  # remove leading whitespace characters
  __trim="${*##[[:space:]]}"
  # remove trailing whitespace characters
  printf "%s" "${__trim%%[[:space:]]}"
}

trim2 " alpha" | od -t x1a
trim2 "beta " | od -t x1a
trim2 "
gamma	" | od -t x1a

trim3() {
  _space=$(echo -n '\b\t\n\v\f\r')
  # remove leading whitespace characters
  __trim="${*##$_space}"
  # remove trailing whitespace characters
  printf "%s" "${__trim%%$_space}"
}

trim2 " alpha" | od -t x1a
trim2 "beta " | od -t x1a
trim2 "
gamma	" | od -t x1a

-------------- next part --------------
#!/bin/dash -vx

trim() {
  # remove leading whitespace characters
  __trim="${*#${*%%[![:space:]]*}}"
  # remove trailing whitespace characters
  printf "%s" "${__trim%${__trim##*[![:space:]]}}"
}

trim " alpha" | od -t x1a
+ trim  alpha
+ __trim=alpha
+ printf %s alpha
+ od -t x1a
0000000  61  6c  70  68  61
          a   l   p   h   a
0000005
trim "beta " | od -t x1a
+ trim beta 
+ __trim=beta 
+ printf %s beta
+ od -t x1a
0000000  62  65  74  61
          b   e   t   a
0000004
trim "
gamma	" | od -t x1a
+ trim 
gamma	
+ __trim=gamma	
+ printf %s gamma
+ od -t x1a
0000000  67  61  6d  6d  61
          g   a   m   m   a
0000005

trim2() {
  # remove leading whitespace characters
  __trim="${*##[[:space:]]}"
  # remove trailing whitespace characters
  printf "%s" "${__trim%%[[:space:]]}"
}

trim2 " alpha" | od -t x1a
+ trim2  alpha
+ __trim=alpha
+ printf %s alpha
+ od -t x1a
0000000  61  6c  70  68  61
          a   l   p   h   a
0000005
trim2 "beta " | od -t x1a
+ trim2 beta 
+ __trim=beta 
+ printf %s beta
+ od -t x1a
0000000  62  65  74  61
          b   e   t   a
0000004
trim2 "
gamma	" | od -t x1a
+ trim2 
gamma	
+ __trim=gamma	
+ printf %s gamma
+ od -t x1a
0000000  67  61  6d  6d  61
          g   a   m   m   a
0000005

trim3() {
  _space=$(echo -n '\b\t\n\v\f\r')
  # remove leading whitespace characters
  __trim="${*##$_space}"
  # remove trailing whitespace characters
  printf "%s" "${__trim%%$_space}"
}

trim2 " alpha" | od -t x1a
+ trim2  alpha
+ __trim=alpha
+ printf %s alpha
+ od -t x1a
0000000  61  6c  70  68  61
          a   l   p   h   a
0000005
trim2 "beta " | od -t x1a
+ trim2 beta 
+ __trim=beta 
+ printf %s beta
+ od -t x1a
0000000  62  65  74  61
          b   e   t   a
0000004
trim2 "
gamma	" | od -t x1a
+ trim2 
gamma	
+ __trim=gamma	
+ printf %s gamma
+ od -t x1a
0000000  67  61  6d  6d  61
          g   a   m   m   a
0000005

-------------- next part --------------
#!/bin/dash -vx

trim() {
  # remove leading whitespace characters
  __trim="${*#${*%%[![:space:]]*}}"
  # remove trailing whitespace characters
  printf "%s" "${__trim%${__trim##*[![:space:]]}}"
}

trim " alpha" | od -t x1a
+ trim  alpha
+ __trim=
+ printf %s 
+ od -t x1a
0000000
trim "beta " | od -t x1a
+ trim beta 
+ __trim=
+ printf %s 
+ od -t x1a
0000000
trim "
gamma	" | od -t x1a
+ trim 
gamma	
+ __trim=
+ printf %s 
+ od -t x1a
0000000

trim2() {
  # remove leading whitespace characters
  __trim="${*##[[:space:]]}"
  # remove trailing whitespace characters
  printf "%s" "${__trim%%[[:space:]]}"
}

trim2 " alpha" | od -t x1a
+ trim2  alpha
+ __trim= alpha
+ printf %s  alpha
+ od -t x1a
0000000  20  61  6c  70  68  61
         sp   a   l   p   h   a
0000006
trim2 "beta " | od -t x1a
+ trim2 beta 
+ __trim=beta 
+ printf %s beta 
+ od -t x1a
0000000  62  65  74  61  20
          b   e   t   a  sp
0000005
trim2 "
gamma	" | od -t x1a
+ trim2 
gamma	
+ __trim=
gamma	
+ printf %s 
gamma	
+ od -t x1a
0000000  0d  67  61  6d  6d  61  09
         cr   g   a   m   m   a  ht
0000007

trim3() {
  _space=$(echo -n '\b\t\n\v\f\r')
  # remove leading whitespace characters
  __trim="${*##$_space}"
  # remove trailing whitespace characters
  printf "%s" "${__trim%%$_space}"
}

trim2 " alpha" | od -t x1a
+ trim2  alpha
+ __trim= alpha
+ printf %s  alpha
+ od -t x1a
0000000  20  61  6c  70  68  61
         sp   a   l   p   h   a
0000006
trim2 "beta " | od -t x1a
+ trim2 beta 
+ __trim=beta 
+ printf %s beta 
+ od -t x1a
0000000  62  65  74  61  20
          b   e   t   a  sp
0000005
trim2 "
gamma	" | od -t x1a
+ trim2 
gamma	
+ __trim=
gamma	
+ printf %s 
gamma	
+ od -t x1a
0000000  0d  67  61  6d  6d  61  09
         cr   g   a   m   m   a  ht
0000007