Own directories of a joining module carry setgid, to an engine that takes it (hq ADR 0334 v4)

internal/catalogue/declaration.go

@@ -262,8 +262,8 @@ type Rendering struct {
 	TakenLibraries map[string]bool
 	LibraryPaths   map[string][]string
 	// RunnerJoinsOwnGroups says this machine's engine puts the tool runner's account in a joining module's own group
-	// (novox/hq ADR 0334 §2: its statement's contract is link.OwnGroupContract or later); to an older one the
-	// identity's runner is not sent.
+	// and takes a directory's setgid mode (novox/hq ADR 0334 §1, §2: its statement's contract is link.OwnGroupContract
+	// or later); to an older one neither the identity's runner nor the setgid bit is sent.
 	RunnerJoinsOwnGroups bool
 }
 
@@ -1062,7 +1062,7 @@ func (r Resolution) compose(with Rendering, owner map[string]string,
 			// And its identity and libraries, where it joins (novox/hq ADR 0328 §4, §5, §10): after the placement's
 			// owner, which a joining module may not set.
 			if joins {
-				if err := joinedInto(copied, m, joined, libPaths); err != nil {
+				if err := joinedInto(copied, m, joined, libPaths, with.RunnerJoinsOwnGroups); err != nil {
 					return nil, err
 				}
 			}