`basic_string: construction from null is not valid` crash with `-O2` and `--input-from-stdin`

[compumike]

I'm experiencing a crash that happens on -O2 or higher when used with a model file on the command line plus --input-from-stdin for a data file.

./minizinc -O2 --input-from-stdin aust_with_data.mzn <aust_with_data.dzn ; echo $?
basic_string: construction from null is not valid
1

./minizinc -O2 --input-from-stdin aust_with_data.mzn aust_with_data.dzn </dev/null ; echo $?
wa=3     nt=2    sa=1
q=3      nsw=2   v=3
t=1
----------
0

./minizinc -O2 aust_with_data.mzn aust_with_data.dzn ; echo $?
wa=3     nt=2    sa=1
q=3      nsw=2   v=3
t=1
----------
0

Workaround

My workaround is to write my data to a temporary .dzn file, rather than using --input-with-stdin.

MiniZinc version

Same crash happens when using MiniZincIDE-2.9.5-x86_64.AppImage MiniZincIDE-build2394518486-x86_64.AppImage. Linux. ./minizinc is symlinked to the AppImage, which is chmod a+x executable.

Test files

aust_with_data.mzn:

% Colouring Australia using nc colours
int: nc;

var 1..nc: wa;   var 1..nc: nt;  var 1..nc: sa;   var 1..nc: q;
var 1..nc: nsw;  var 1..nc: v;   var 1..nc: t;

constraint wa != nt;
constraint wa != sa;
constraint nt != sa;
constraint nt != q;
constraint sa != q;
constraint sa != nsw;
constraint sa != v;
constraint q != nsw;
constraint nsw != v;
solve satisfy;

output ["wa=\(wa)\t nt=\(nt)\t sa=\(sa)\n",
        "q=\(q)\t nsw=\(nsw)\t v=\(v)\n",
         "t=", show(t),  "\n"];

aust_with_data.dzn:

nc = 3;

[compumike]

libminizinc/lib/passes/compile_pass.cpp

Lines 36 to 37 in 96ebc4b

	ASTString strip_stdlib_path(const vector<string>& includePaths, const ASTString& fs) {
	std::string f(fs.c_str());

will break with the observed basic_string: construction from null is not valid if fs.c_str() == NULL.

This is called from:

libminizinc/lib/passes/compile_pass.cpp

Line 73 in 96ebc4b

include_names.push_back(strip_stdlib_path(new_includePaths, inc->m()->filepath()));

So we have to look for where filepath is set.

---

lib/parser.cpp void parse(...)

In the !isModelString side of the branch, m->setFilepath gets called:

libminizinc/lib/parser.cpp

Lines 265 to 267 in 96ebc4b

	if (m->filepath().empty()) {
	m->setFilepath(fullname);
	}

But in the isModelString side of the branch, nothing ever calls m->setFilepath:

libminizinc/lib/parser.cpp

Lines 269 to 273 in 96ebc4b

	} else {
	isFzn = false;
	fullname = f;
	s = parentPath;
	}