feat(code-graph): directory-scoped resolution (SameDirectory) for HCL

Author: Michael Usachenko

crates/code-graph/src/v2/linker/imports.rs

@@ -23,6 +23,12 @@ pub struct ResolveSettings {
     /// Maximum number of results from `global_name` before discarding
     /// as too ambiguous. Prevents fan-out on common names.
     pub global_name_max_results: usize,
+    /// When set, restrict the qualified-name fast path (resolver.rs) to
+    /// definitions in the SAME DIRECTORY as the referencing file. For
+    /// languages whose module scope is a directory (Terraform/HCL), this
+    /// stops a `local.x` / `type.name` reference from resolving to a
+    /// same-named definition in an unrelated module directory.
+    pub same_directory_scope: bool,
 }
 
 impl Default for ResolveSettings {
@@ -34,10 +40,20 @@ impl Default for ResolveSettings {
             compound_key_recovery: true,
             implicit_scope_on_base: true,
             global_name_max_results: 5,
+            same_directory_scope: false,
         }
     }
 }
 
+/// The directory portion of a file path (everything before the last `/`),
+/// or `""` for a repo-root file. Used for directory-scoped resolution.
+pub(crate) fn dir_of(path: &str) -> &str {
+    match path.rfind('/') {
+        Some(i) => &path[..i],
+        None => "",
+    }
+}
+
 // ── ImportResolver ──────────────────────────────────────────────
 
 /// Per-file import resolver. Holds shared state so individual
@@ -381,3 +397,28 @@ impl<'a> ImportResolver<'a> {
             .collect()
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::dir_of;
+
+    #[test]
+    fn dir_of_nested_path() {
+        assert_eq!(dir_of("modules/vpc/main.tf"), "modules/vpc");
+    }
+
+    #[test]
+    fn dir_of_root_file() {
+        assert_eq!(dir_of("main.tf"), "");
+    }
+
+    #[test]
+    fn dir_of_empty() {
+        assert_eq!(dir_of(""), "");
+    }
+
+    #[test]
+    fn dir_of_trailing_slash() {
+        assert_eq!(dir_of("a/b/"), "a/b");
+    }
+}

crates/code-graph/src/v2/linker/resolver.rs

@@ -657,7 +657,23 @@ impl<'a> ResolveCtx<'a> {
                 .by_fqn
                 .lookup(r.name, |idx| self.graph.def_fqn(idx) == r.name);
             if !matches.is_empty() {
-                return Ok(matches.to_vec());
+                if self.settings.same_directory_scope {
+                    // Directory-scoped languages (HCL): a qualified ref such as
+                    // `local.x` / `aws_vpc.this` only addresses its own module
+                    // (directory). Keep same-directory matches; if none, fall
+                    // through rather than bind to an unrelated module's def.
+                    let dir = super::imports::dir_of(self.graph.graph[self.file_node].path());
+                    let same: Vec<_> = matches
+                        .iter()
+                        .copied()
+                        .filter(|&idx| super::imports::dir_of(self.graph.graph[idx].path()) == dir)
+                        .collect();
+                    if !same.is_empty() {
+                        return Ok(same);
+                    }
+                } else {
+                    return Ok(matches.to_vec());
+                }
             }
         }