fix: resolve barrel resolution quality and cycle regression (#848)

* refactor(native): extract magic numbers to named constants

Extract hardcoded magic numbers to named constants in constants.rs:
- Louvain: MAX_LEVELS=50, MAX_PASSES=20, MIN_GAIN=1e-12, DEFAULT_SEED=42
- Dataflow: TRUNCATION_LIMIT=120
- Build pipeline: FAST_PATH_MAX_CHANGED_FILES=5, FAST_PATH_MIN_EXISTING_FILES=20
Also extract DEFAULT_RANDOM_SEED=42 in TS louvain.ts.

* refactor(native): extract shared barrel resolution into common module

* refactor(native): improve helper and barrel resolution quality

* fix: resolve +1 function cycle regression in barrel resolution

* fix: use i64 type for FAST_PATH_MIN_EXISTING_FILES constant (#848)

The constant is compared against existing_file_count which returns i64
from SQLite. Using usize caused a Rust compile error.

* fix: address Greptile review feedback on barrel resolution and helpers (#848)

Remove redundant guard in barrel_resolution.rs that was always true
at the wildcard/empty-names branch. Eliminate skip_children_on_short_string
flag in helpers.rs by using early return directly from the string match arm.

Author: carlos-alm

crates/codegraph-core/src/barrel_resolution.rs

@@ -0,0 +1,189 @@
+//! Shared barrel-file resolution logic.
+//!
+//! Both `edge_builder.rs` (napi-driven) and `import_edges.rs` (SQLite-driven)
+//! need to recursively resolve a symbol through barrel reexport chains.
+//! This module extracts the common algorithm so both callers share a single
+//! implementation.
+
+use std::collections::HashSet;
+
+/// Minimal view of a single reexport entry, borrowed from the caller's data.
+pub struct ReexportRef<'a> {
+    pub source: &'a str,
+    pub names: &'a [String],
+    pub wildcard_reexport: bool,
+}
+
+/// Trait that abstracts over the different context types in `edge_builder` and
+/// `import_edges`.  Each implementor provides access to its own reexport map
+/// and definition index so the resolution algorithm stays generic.
+pub trait BarrelContext {
+    /// Return the reexport entries for `barrel_path`, or `None` if the path
+    /// has no reexports.
+    fn reexports_for(&self, barrel_path: &str) -> Option<Vec<ReexportRef<'_>>>;
+
+    /// Return `true` if `file_path` contains a definition named `symbol`.
+    fn has_definition(&self, file_path: &str, symbol: &str) -> bool;
+}
+
+/// Recursively resolve a symbol through barrel reexport chains.
+///
+/// Mirrors `resolveBarrelExport()` in `resolve-imports.ts`.
+/// The caller provides a `visited` set to prevent infinite loops on circular
+/// reexport chains.
+pub fn resolve_barrel_export<'a, C: BarrelContext>(
+    ctx: &'a C,
+    barrel_path: &str,
+    symbol_name: &str,
+    visited: &mut HashSet<String>,
+) -> Option<String> {
+    if visited.contains(barrel_path) {
+        return None;
+    }
+    visited.insert(barrel_path.to_string());
+
+    let reexports = ctx.reexports_for(barrel_path)?;
+
+    for re in &reexports {
+        // Named reexports (non-wildcard)
+        if !re.names.is_empty() && !re.wildcard_reexport {
+            if re.names.iter().any(|n| n == symbol_name) {
+                if ctx.has_definition(re.source, symbol_name) {
+                    return Some(re.source.to_string());
+                }
+                let deeper = resolve_barrel_export(ctx, re.source, symbol_name, visited);
+                if deeper.is_some() {
+                    return deeper;
+                }
+                // Fallback: return source even if no definition found
+                return Some(re.source.to_string());
+            }
+            continue;
+        }
+
+        // Wildcard or empty-names reexports
+        if ctx.has_definition(re.source, symbol_name) {
+            return Some(re.source.to_string());
+        }
+        let deeper = resolve_barrel_export(ctx, re.source, symbol_name, visited);
+        if deeper.is_some() {
+            return deeper;
+        }
+    }
+
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::collections::HashMap;
+
+    struct TestContext {
+        reexports: HashMap<String, Vec<(String, Vec<String>, bool)>>,
+        definitions: HashMap<String, HashSet<String>>,
+    }
+
+    impl BarrelContext for TestContext {
+        fn reexports_for(&self, barrel_path: &str) -> Option<Vec<ReexportRef<'_>>> {
+            self.reexports.get(barrel_path).map(|entries| {
+                entries
+                    .iter()
+                    .map(|(source, names, wildcard)| ReexportRef {
+                        source: source.as_str(),
+                        names: names.as_slice(),
+                        wildcard_reexport: *wildcard,
+                    })
+                    .collect()
+            })
+        }
+
+        fn has_definition(&self, file_path: &str, symbol: &str) -> bool {
+            self.definitions
+                .get(file_path)
+                .map_or(false, |defs| defs.contains(symbol))
+        }
+    }
+
+    #[test]
+    fn resolves_named_reexport() {
+        let mut reexports = HashMap::new();
+        reexports.insert(
+            "src/index.ts".to_string(),
+            vec![("src/utils.ts".to_string(), vec!["foo".to_string()], false)],
+        );
+        let mut definitions = HashMap::new();
+        definitions.insert(
+            "src/utils.ts".to_string(),
+            HashSet::from(["foo".to_string()]),
+        );
+
+        let ctx = TestContext { reexports, definitions };
+        let mut visited = HashSet::new();
+        let result = resolve_barrel_export(&ctx, "src/index.ts", "foo", &mut visited);
+        assert_eq!(result.as_deref(), Some("src/utils.ts"));
+    }
+
+    #[test]
+    fn resolves_wildcard_reexport() {
+        let mut reexports = HashMap::new();
+        reexports.insert(
+            "src/index.ts".to_string(),
+            vec![("src/utils.ts".to_string(), vec![], true)],
+        );
+        let mut definitions = HashMap::new();
+        definitions.insert(
+            "src/utils.ts".to_string(),
+            HashSet::from(["bar".to_string()]),
+        );
+
+        let ctx = TestContext { reexports, definitions };
+        let mut visited = HashSet::new();
+        let result = resolve_barrel_export(&ctx, "src/index.ts", "bar", &mut visited);
+        assert_eq!(result.as_deref(), Some("src/utils.ts"));
+    }
+
+    #[test]
+    fn resolves_transitive_chain() {
+        let mut reexports = HashMap::new();
+        reexports.insert(
+            "src/index.ts".to_string(),
+            vec![("src/mid.ts".to_string(), vec![], true)],
+        );
+        reexports.insert(
+            "src/mid.ts".to_string(),
+            vec![("src/deep.ts".to_string(), vec!["baz".to_string()], false)],
+        );
+        let mut definitions = HashMap::new();
+        definitions.insert(
+            "src/deep.ts".to_string(),
+            HashSet::from(["baz".to_string()]),
+        );
+
+        let ctx = TestContext { reexports, definitions };
+        let mut visited = HashSet::new();
+        let result = resolve_barrel_export(&ctx, "src/index.ts", "baz", &mut visited);
+        assert_eq!(result.as_deref(), Some("src/deep.ts"));
+    }
+
+    #[test]
+    fn prevents_circular_reexport() {
+        let mut reexports = HashMap::new();
+        reexports.insert(
+            "src/a.ts".to_string(),
+            vec![("src/b.ts".to_string(), vec![], true)],
+        );
+        reexports.insert(
+            "src/b.ts".to_string(),
+            vec![("src/a.ts".to_string(), vec![], true)],
+        );
+
+        let ctx = TestContext {
+            reexports,
+            definitions: HashMap::new(),
+        };
+        let mut visited = HashSet::new();
+        let result = resolve_barrel_export(&ctx, "src/a.ts", "missing", &mut visited);
+        assert_eq!(result, None);
+    }
+}

crates/codegraph-core/src/build_pipeline.rs

@@ -18,6 +18,7 @@
 
 use crate::change_detection;
 use crate::config::{BuildConfig, BuildOpts, BuildPathAliases};
+use crate::constants::{FAST_PATH_MAX_CHANGED_FILES, FAST_PATH_MIN_EXISTING_FILES};
 use crate::file_collector;
 use crate::import_edges::{self, ImportEdgeContext};
 use crate::import_resolution;
@@ -492,7 +493,7 @@ pub fn run_pipeline(
     // reverse-dep files added for edge rebuilding, which inflates the count
     // and would skip the fast path even for single-file incremental builds.
     let use_fast_path =
-        !change_result.is_full_build && parse_changes.len() <= 5 && existing_file_count > 20;
+        !change_result.is_full_build && parse_changes.len() <= FAST_PATH_MAX_CHANGED_FILES && existing_file_count > FAST_PATH_MIN_EXISTING_FILES;
 
     if use_fast_path {
         structure::update_changed_file_metrics(

crates/codegraph-core/src/constants.rs

@@ -1,3 +1,30 @@
 /// Maximum recursion depth for AST traversal to prevent stack overflow
 /// on deeply nested trees. Used by extractors, complexity, CFG, and dataflow.
 pub const MAX_WALK_DEPTH: usize = 200;
+
+// ─── Louvain community detection ────────────────────────────────────
+
+/// Maximum number of coarsening levels in the Louvain algorithm.
+pub const LOUVAIN_MAX_LEVELS: usize = 50;
+
+/// Maximum number of local-move passes per level before stopping.
+pub const LOUVAIN_MAX_PASSES: usize = 20;
+
+/// Minimum modularity gain to accept a node move (avoids floating-point noise).
+pub const LOUVAIN_MIN_GAIN: f64 = 1e-12;
+
+/// Default random seed for deterministic community detection.
+pub const DEFAULT_RANDOM_SEED: u32 = 42;
+
+// ─── Dataflow analysis ──────────────────────────────────────────────
+
+/// Maximum character length for truncated dataflow expressions.
+pub const DATAFLOW_TRUNCATION_LIMIT: usize = 120;
+
+// ─── Build pipeline ─────────────────────────────────────────────────
+
+/// Maximum number of changed files eligible for the incremental fast path.
+pub const FAST_PATH_MAX_CHANGED_FILES: usize = 5;
+
+/// Minimum existing file count required before the fast path is considered.
+pub const FAST_PATH_MIN_EXISTING_FILES: i64 = 20;

crates/codegraph-core/src/dataflow.rs

@@ -1,7 +1,7 @@
 use std::collections::HashMap;
 use tree_sitter::{Node, Tree};
 
-use crate::constants::MAX_WALK_DEPTH;
+use crate::constants::{DATAFLOW_TRUNCATION_LIMIT, MAX_WALK_DEPTH};
 use crate::types::{
     DataflowArgFlow, DataflowAssignment, DataflowMutation, DataflowParam, DataflowResult,
     DataflowReturn,
@@ -1196,7 +1196,7 @@ fn handle_var_declarator(
                 var_name: n.clone(),
                 caller_func: Some(func_name.clone()),
                 source_call_name: callee.clone(),
-                expression: truncate(node_text(node, source), 120),
+                expression: truncate(node_text(node, source), DATAFLOW_TRUNCATION_LIMIT),
                 line: node_line(node),
             });
             scope
@@ -1209,7 +1209,7 @@ fn handle_var_declarator(
             var_name: var_name.clone(),
             caller_func: Some(func_name),
             source_call_name: callee.clone(),
-            expression: truncate(node_text(node, source), 120),
+            expression: truncate(node_text(node, source), DATAFLOW_TRUNCATION_LIMIT),
             line: node_line(node),
         });
         scope.locals.insert(var_name, LocalSource::CallReturn { callee });
@@ -1245,7 +1245,7 @@ fn handle_assignment(
                         func_name: Some(func_name.clone()),
                         receiver_name: receiver,
                         binding_type: binding.as_ref().map(|b| b.binding_type.clone()),
-                        mutating_expr: truncate(node_text(node, source), 120),
+                        mutating_expr: truncate(node_text(node, source), DATAFLOW_TRUNCATION_LIMIT),
                         line: node_line(node),
                     });
                 }
@@ -1264,7 +1264,7 @@ fn handle_assignment(
                         var_name: var_name.clone(),
                         caller_func: Some(func_name),
                         source_call_name: callee.clone(),
-                        expression: truncate(node_text(node, source), 120),
+                        expression: truncate(node_text(node, source), DATAFLOW_TRUNCATION_LIMIT),
                         line: node_line(node),
                     });
                     if let Some(scope) = scope_stack.last_mut() {
@@ -1340,7 +1340,7 @@ fn handle_call_expr(
                     arg_name: Some(tracked.clone()),
                     binding_type: binding.as_ref().map(|b| b.binding_type.clone()),
                     confidence: conf,
-                    expression: truncate(node_text(&arg_raw, source), 120),
+                    expression: truncate(node_text(&arg_raw, source), DATAFLOW_TRUNCATION_LIMIT),
                     line: node_line(node),
                 });
             }
@@ -1442,7 +1442,7 @@ fn handle_expr_stmt_mutation(
             func_name,
             receiver_name: recv,
             binding_type: binding.as_ref().map(|b| b.binding_type.clone()),
-            mutating_expr: truncate(node_text(&expr, source), 120),
+            mutating_expr: truncate(node_text(&expr, source), DATAFLOW_TRUNCATION_LIMIT),
             line: node_line(node),
         });
     }