GlobDistdir: check for glob usage with DISTDIR

Resolves: #605
Signed-off-by: Arthur Zamarin <arthurzam@gentoo.org>

src/pkgcheck/checks/codingstyle.py

@@ -1363,3 +1363,37 @@ def feed(self, pkg):
             call_name = pkg.node_str(call_node.child_by_field_name("name"))
             if call_name in ("head", "tail"):
                 yield from self.check_head_tail(pkg, call_node, call_name)
+
+
+class GlobDistdir(results.LineResult, results.Warning):
+    """Filename expansion with ``${DISTDIR}`` is unsafe.
+
+    Filename expansion could accidentally match irrelevant files in
+    ``${DISTDIR}``, e.g. from other packages or other versions of the
+    same package.
+    """
+
+    @property
+    def desc(self):
+        return f"line {self.lineno}: unsafe filename expansion used with DISTDIR: {self.line}"
+
+
+class GlobCheck(Check):
+    """Scan ebuilds for unsafe glob usage."""
+
+    _source = sources.EbuildParseRepoSource
+    known_results = frozenset({GlobDistdir})
+
+    def __init__(self, options, **kwargs):
+        super().__init__(options, **kwargs)
+        self.glob_query = bash.query('(concatenation (word) @word (.match? @word "[*?]")) @usage')
+
+    def feed(self, pkg):
+        for node, capture in self.glob_query.captures(pkg.tree.root_node):
+            if capture == "usage":
+                for var_node, _ in bash.var_query.captures(node):
+                    var_name = pkg.node_str(var_node)
+                    if var_name == "DISTDIR":
+                        lineno, _colno = node.start_point
+                        yield GlobDistdir(line=pkg.node_str(node), lineno=lineno + 1, pkg=pkg)
+                        break

testdata/data/repos/standalone/GlobCheck/GlobDistdir/expected.json

@@ -0,0 +1,3 @@
+{"__class__": "GlobDistdir", "category": "GlobCheck", "package": "GlobDistdir", "version": "0", "line": "\"${DISTDIR}\"/foo-*.bar", "lineno": 7}
+{"__class__": "GlobDistdir", "category": "GlobCheck", "package": "GlobDistdir", "version": "0", "line": "\"${DISTDIR}\"/\"${DISTDIR}\"/foo-?.bar", "lineno": 8}
+{"__class__": "GlobDistdir", "category": "GlobCheck", "package": "GlobDistdir", "version": "0", "line": "\"${DISTDIR}\"/foo-?-*.bar", "lineno": 9}

testdata/repos/standalone/GlobCheck/GlobDistdir/GlobDistdir-0.ebuild

@@ -0,0 +1,15 @@
+DESCRIPTION="Ebuild with unsafe glob around DISTDIR"
+HOMEPAGE="https://github.com/pkgcore/pkgcheck"
+SLOT="0"
+LICENSE="BSD"
+
+src_install() {
+	doins "${DISTDIR}"/foo-*.bar # bad
+	doins "${DISTDIR}"/"${DISTDIR}"/foo-?.bar # bad
+	doins "${DISTDIR}"/foo-?-*.bar # bad
+
+	doins "${T}"/foo-*.bar # not unsafe dir
+	doins "${DISTDIR}"/foo-1.bar # no glob
+	doins "${DISTDIR}"/"foo-*.bar" # quoted
+	doins "${DISTDIR}"/'foo-*.bar' # quoted
+}