Modify zsh commands to forward errors - error-handling

Question

I would like to modify one of my recent Bash aliases to forward errors. Here is the alias:
alias makecclip=
"make |& tee >(sed \"s,\x1B\[[0-9;]*[a-zA-Z],,g\" |
egrep \":[0-9]+:[0-9]+: error\" | cut -d : -f1,2,3 |
head -n 1 | xargs -0 echo -n | xclip -selection clipboard &&
xclip -selection clipboard -o)
This code displays the results of a C++ compilation, and then removes formatting and displays and adds to the clipboard the first error location (if there is any).
However, I would like to use this code like this:
makecclip && bin/someexecutablecreated
This though ruins the && operator, since it always runs bin/someexecutablecreated even when there is a compilation error present. How can I add modifications to the code to set the error flag, when the error list (the things saved to clipboard and echoed) is not empty?

Answer 1

You can address your issue by using the PIPESTATUS internal variable (this variable has other names in non-bash shells). This allows to have an history of exit statuses of commands passed by pipe.
You precised in the comments that you didn't use bash, but used zsh instead. As such, some of the syntax of my solution has to be changed, as they handle the PIPESTATUS variable differently.
In bash, you use ${PIPESTATUS[0]}, whereas you'll use ${pipestatus[1]} in zsh.
A first approach, using your existing alias, could be as follow :
makecclip && [ "${pipestatus[1]}" -eq "0" ] && echo "ok"
This runs the echo command only if "${pipestatus[1]}" is equal to 0 (no errors during make)
A more convenient solution would be to use a function instead of an alias for makecclip. In your ~/.bashrc file, you could write :
makecclip () {
make |& tee >(sed "s,\x1B\[[0-9;]*[a-zA-Z],,g" | egrep ":[0-9]+:[0-9]+: error" | cut -d : -f1,2,3 | head -n 1 | xargs -0 echo -n | xclip -selection clipboard && xclip -selection clipboard -o)
return "${pipestatus[1]}"
}
Now, makecclip && echo "ok" will work as expected.
Test cases :
#!/bin/zsh
#do not run this test if there is an existing makefile in your current directory
rm -f makefile
makecclip () {
make |& tee >(sed "s,\x1B\[[0-9;]*[a-zA-Z],,g" | egrep ":[0-9]+:[0-9]+: error" | cut -d : -f1,2,3 | head -n 1 | xargs -0 echo -n | xclip -selection clipboard && xclip -selection clipboard -o)
# this part is only present to check the pipestatus values during the tests.
# In the real function, I wrote 'return ${pipestatus[1]}' instead.
a=(${pipestatus[#]})
echo ${a[#]}
return ${a[1]}
}
echo "# no makefile"
makecclip && echo "ok"
echo -e "\n# empty makefile"
touch makefile
makecclip && echo "ok"
echo -e "\n# dummy makefile entry"
echo -e 'a:\n\t#echo "inside makefile"' > makefile
makecclip && echo "ok"
echo -e "\n# program with error makefile"
echo -e "int main(){error; return 0;}" > target.cc
echo -e 'a:\n\tgcc target.cc' > makefile
makecclip && echo "ok"
Output :
$ ./test.sh
# no makefile
make: *** No targets specified and no makefile found. Stop.
2 0
# empty makefile
make: *** No targets. Stop.
2 0
# dummy makefile entry
inside makefile
0 0
ok
# program with error
gcc target.cc
target.cc: In function ‘int main()’:
target.cc:1:12: error: ‘error’ was not declared in this scope
int main(){error; return 0;}
^
makefile:2: recipe for target 'a' failed
make: *** [a] Error 1
target.cc:1:12
2 0