Sourcing PKGBUILDs might change variables used
E.g. toru used _repo while a PKGBUILD changed the value of this variable, making fullpkg ignore dependencies from the community repo. There should be another solution which wouldn't lead to difficult to debug problems.
Updated by mtjm almost 8 years ago
This problem would be certainly fixed by writing and using a script which would source the PKGBUILD in a different process (properly, with e.g. CARCH defined) and output a script setting specified variables. Then we could implement e.g. caching for it in a single place, so it wouldn't be much slower.
Updated by lukeshu about 7 years ago
Also, there are several approaches to this that are used by makepkg and devtools.
- Source them in a subshell and print the results.
VAR="$(. FILE; echo $VAR)"
- Extract the line that sets it using grep, and `eval` it.
eval $(grep '^\s*VAR=' FILE)
They both have the possibility to run side-effects. The first is more "correct" and rubust, but is more likely to run unintentional side effects in a poorly written PKGBUILD.
Updated by mtjm about 7 years ago
- Source them in a subshell and print the results. [...]
It will work, not sure about spaces in variables; arrays need different handling. (I have written a script outputting it with nul-separated fields, seems robust although nonobvious to use in shell scripts.)
- Extract the line that sets it using grep, and `eval` it. [...]
This certainly won't work for makedepends in many mips64el PKGBUILDs, with ifs and +=s.
Updated by lukeshu over 6 years ago
Definitely source makepkg.conf (actually, <tt>load_files makepkg</tt>) if we need to set CARCH. But is setting CARCH important?
Also, as far as exporting arrays from a subshell:
eval "$(. FILE &>/dev/null; declare -ap VARNAME)"
Other than the possibility of FILE having side-effects, I believe that the only caveat to that is that if it is done in a function, it will be local to that function.
Updated by lukeshu almost 3 years ago
I'd kind of like to move everything to use
makepkg --printsrcinfo. It would be a nice sanitization layer between the PKGBUILD and our runtime. There's a Python parser for the format. I suppose there's also a PHP parser that is part of AUR4. It's an easy format. It would also make it easier to move some of the tooling to a better language than Bash.