docs: add re-exporter detection implementation plan

docs/superpowers/plans/2026-03-22-reexporter-detection-fix.md

@@ -0,0 +1,175 @@
+# Fix Re-exporter Detection for own<T> Result Transfers
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** Fix `callee_defines_resource` detection for re-exporting intermediates so own<T> result transfers work in 3-component chains, unblocking resource_floats and xcrate fixtures.
+
+**Architecture:** Replace `is_reexporter()` (checks graph edge type, fails for cross-name re-exports) with `imports_resource_from_definer()` (follows ResolvesTo edges to check if import target is a known definer). The synthesis and merger wiring already handle `callee_defines_resource=false` correctly — they just need the right value.
+
+**Tech Stack:** Rust, petgraph
+
+---
+
+## Task 1: Add `imports_resource_from_definer` to ResourceGraph
+
+**Files:**
+- Modify: `meld-core/src/resource_graph.rs` (after `is_reexporter`, ~line 385)
+
+- [ ] **Step 1: Add the method**
+
+After `is_reexporter`, add:
+
+```rust
+/// Does this component import the given resource from a component that IS
+/// the known definer? If so, this component is a re-exporter — not a definer.
+///
+/// Follows `ResolvesTo` edges from this component to find target components,
+/// then checks if any target is in `defines_cache` for this resource name.
+/// Correctly distinguishes:
+/// - resource_floats comp 3: imports "float" from comp 0 (definer) → true
+/// - xcrate comp 0: imports from another comp that is NOT the "x" definer → false
+pub fn imports_resource_from_definer(&self, comp_idx: usize, resource_name: &str) -> bool {
+    if let Some(&comp_node) = self.comp_nodes.get(&comp_idx) {
+        for edge in self
+            .graph
+            .edges_directed(comp_node, petgraph::Direction::Outgoing)
+        {
+            if let GraphEdge::ResolvesTo { .. } = edge.weight() {
+                if let GraphNode::Component(target_comp) = self.graph[edge.target()] {
+                    if target_comp == comp_idx {
+                        continue; // skip self-imports
+                    }
+                    let target_defines = self
+                        .defines_cache
+                        .keys()
+                        .any(|(idx, _, rn)| *idx == target_comp && rn == resource_name);
+                    if target_defines {
+                        return true;
+                    }
+                }
+            }
+        }
+    }
+    false
+}
+```
+
+- [ ] **Step 2: Build to verify**
+
+Run: `cargo build 2>&1 | tail -3`
+Expected: Clean build
+
+- [ ] **Step 3: Commit**
+
+## Task 2: Use `imports_resource_from_definer` in graph override (per-function path)
+
+**Files:**
+- Modify: `meld-core/src/resolver.rs:2116-2131` (per-function path graph override)
+
+- [ ] **Step 1: Replace `is_reexporter` with `imports_resource_from_definer`**
+
+At line ~2116 and ~2128, change:
+
+```rust
+// BEFORE:
+} else if rg.is_reexporter(*to_comp, iface, rn) {
+    op.callee_defines_resource = false;
+}
+
+// AFTER:
+} else if rg.imports_resource_from_definer(*to_comp, rn) {
+    op.callee_defines_resource = false;
+}
+```
+
+Do this for BOTH the params loop (~2116) and results loop (~2128).
+
+- [ ] **Step 2: Build to verify**
+
+Run: `cargo build 2>&1 | tail -3`
+
+- [ ] **Step 3: Commit**
+
+## Task 3: Use `imports_resource_from_definer` in graph override (fallback path)
+
+**Files:**
+- Modify: `meld-core/src/resolver.rs:2325,2336` (fallback path graph override)
+
+- [ ] **Step 1: Replace `is_reexporter` with `imports_resource_from_definer`**
+
+Same change as Task 2, but in the fallback path at lines ~2325 and ~2336.
+
+- [ ] **Step 2: Build to verify**
+
+- [ ] **Step 3: Commit**
+
+## Task 4: Promote resource_floats to runtime test and verify
+
+**Files:**
+- Modify: `meld-core/tests/wit_bindgen_runtime.rs:653`
+
+- [ ] **Step 1: Change resource_floats from fuse_only to runtime**
+
+```rust
+// BEFORE:
+fuse_only_test!(test_fuse_wit_bindgen_resource_floats, "resource_floats");
+
+// AFTER:
+runtime_test!(test_runtime_wit_bindgen_resource_floats, "resource_floats");
+```
+
+- [ ] **Step 2: Run resource_floats test**
+
+Run: `cargo test --package meld-core --test wit_bindgen_runtime test_runtime_wit_bindgen_resource_floats -- --nocapture 2>&1 | tail -5`
+Expected: PASS (if synthesis+wiring works) or FAIL with different error (adapter can't find rep/new func)
+
+- [ ] **Step 3: If FAIL — check if synthesis produced the imports**
+
+Run: `RUST_LOG=warn cargo test --package meld-core --test wit_bindgen_runtime test_runtime_wit_bindgen_resource_floats -- --nocapture 2>&1 | grep -i 'resource\|own.*result\|no callee'`
+
+If "no callee [resource-rep]" warning appears, the synthesis didn't generate the callee's rep for the re-exporter adapters. Check that the synthesis loop at resolver.rs:1141-1147 fires for the newly-downgraded `callee_defines_resource=false` results.
+
+**KEY ISSUE:** The synthesis runs AFTER identify_adapter_sites. Since the graph override sets `callee_defines_resource=false` during adapter site identification, the synthesis at line 1143 should automatically pick it up. If it doesn't, check whether the adapter sites are being re-created or whether the requirements are populated before the graph override runs.
+
+- [ ] **Step 4: If PASS — run full suite for regressions**
+
+Run: `cargo test 2>&1 | grep -E 'FAILED|test result:'`
+Expected: All pass (xcrate may also be fixed by the same change)
+
+- [ ] **Step 5: Run clippy**
+
+Run: `cargo +stable clippy --all-targets -- -D warnings 2>&1 | tail -5`
+Expected: Clean
+
+- [ ] **Step 6: If resource_floats passes and no regressions — commit**
+
+If xcrate also passes, update the comment at line 653 to remove resource_floats from the known failures list.
+
+## Task 5: Final verification and PR
+
+- [ ] **Step 1: Run full test suite**
+
+Run: `cargo test 2>&1`
+Expected: All tests pass
+
+- [ ] **Step 2: Commit all changes**
+
+```bash
+git checkout -b fix/reexporter-detection
+git add meld-core/src/resource_graph.rs meld-core/src/resolver.rs meld-core/tests/wit_bindgen_runtime.rs
+git commit -m "fix: detect re-exporters via composition DAG for own<T> result transfers
+
+Replace is_reexporter (checks graph edge type) with imports_resource_from_definer
+(follows ResolvesTo edges to verify import target is a known definer). This
+correctly distinguishes:
+- resource_floats comp 3: imports from definer → re-exporter → callee_defines=false
+- xcrate comp 0: imports from non-definer → bridge → callee_defines unchanged
+
+The synthesis and merger wiring already handle callee_defines=false correctly.
+
+Fixes: resource_floats, potentially xcrate"
+```
+
+- [ ] **Step 3: Push and create PR**
+
+- [ ] **Step 4: Merge PR**