Reanalyze server: invalidate cache on config change

CHANGELOG.md

@@ -20,6 +20,8 @@
 
 #### :bug: Bug fix
 
+- Reanalyze server: invalidate cache and recompute results when config changes in `rescript.json`. https://github.com/rescript-lang/rescript/pull/8262
+
 #### :memo: Documentation
 
 #### :nail_care: Polish

analysis/reanalyze/src/ReanalyzeServer.ml

@@ -96,6 +96,14 @@ module Server = struct
     let s = Gc.quick_stat () in
     mb_of_words s.live_words
 
+  type reactive_pipeline = {
+    dce_config: DceConfig.t;
+    reactive_collection: ReactiveAnalysis.t;
+    reactive_merge: ReactiveMerge.t;
+    reactive_liveness: ReactiveLiveness.t;
+    reactive_solver: ReactiveSolver.t;
+  }
+
   type server_state = {
     parse_argv: string array -> string option;
     run_analysis:
@@ -111,12 +119,9 @@ module Server = struct
       unit;
     config: server_config;
     cmtRoot: string option;
-    dce_config: DceConfig.t;
-    reactive_collection: ReactiveAnalysis.t;
-    reactive_merge: ReactiveMerge.t;
-    reactive_liveness: ReactiveLiveness.t;
-    reactive_solver: ReactiveSolver.t;
+    mutable pipeline: reactive_pipeline;
     stats: server_stats;
+    mutable config_snapshot: RunConfig.snapshot;
   }
 
   type request_info = {
@@ -261,6 +266,32 @@ Examples:
         unlink_if_exists stderr_path)
       run
 
+  let create_reactive_pipeline () : reactive_pipeline =
+    let dce_config = DceConfig.current () in
+    let reactive_collection = ReactiveAnalysis.create ~config:dce_config in
+    let file_data_collection =
+      ReactiveAnalysis.to_file_data_collection reactive_collection
+    in
+    let reactive_merge = ReactiveMerge.create file_data_collection in
+    let reactive_liveness = ReactiveLiveness.create ~merged:reactive_merge in
+    let value_refs_from =
+      if dce_config.DceConfig.run.transitive then None
+      else Some reactive_merge.ReactiveMerge.value_refs_from
+    in
+    let reactive_solver =
+      ReactiveSolver.create ~decls:reactive_merge.ReactiveMerge.decls
+        ~live:reactive_liveness.ReactiveLiveness.live
+        ~annotations:reactive_merge.ReactiveMerge.annotations ~value_refs_from
+        ~config:dce_config
+    in
+    {
+      dce_config;
+      reactive_collection;
+      reactive_merge;
+      reactive_liveness;
+      reactive_solver;
+    }
+
   let init_state ~(parse_argv : string array -> string option)
       ~(run_analysis :
          dce_config:DceConfig.t ->
@@ -291,39 +322,16 @@ Examples:
              server with editor-like args only."
             !Cli.churn
         else
-          let dce_config = DceConfig.current () in
-          let reactive_collection =
-            ReactiveAnalysis.create ~config:dce_config
-          in
-          let file_data_collection =
-            ReactiveAnalysis.to_file_data_collection reactive_collection
-          in
-          let reactive_merge = ReactiveMerge.create file_data_collection in
-          let reactive_liveness =
-            ReactiveLiveness.create ~merged:reactive_merge
-          in
-          let value_refs_from =
-            if dce_config.DceConfig.run.transitive then None
-            else Some reactive_merge.ReactiveMerge.value_refs_from
-          in
-          let reactive_solver =
-            ReactiveSolver.create ~decls:reactive_merge.ReactiveMerge.decls
-              ~live:reactive_liveness.ReactiveLiveness.live
-              ~annotations:reactive_merge.ReactiveMerge.annotations
-              ~value_refs_from ~config:dce_config
-          in
+          let pipeline = create_reactive_pipeline () in
           Ok
             {
               parse_argv;
               run_analysis;
               config;
               cmtRoot;
-              dce_config;
-              reactive_collection;
-              reactive_merge;
-              reactive_liveness;
-              reactive_solver;
+              pipeline;
               stats = {request_count = 0};
+              config_snapshot = RunConfig.snapshot ();
             })
 
   let run_one_request (state : server_state) (_req : request) :
@@ -347,6 +355,17 @@ Examples:
         (* Always run from the server's project root; client cwd is not stable in VS Code. *)
         state.config.cwd (fun () ->
           capture_stdout_stderr (fun () ->
+              (* Re-read config from rescript.json to detect changes.
+                 If changed, recreate the entire reactive pipeline from scratch. *)
+              RunConfig.reset ();
+              Paths.Config.processConfig ();
+              let new_snapshot = RunConfig.snapshot () in
+              if
+                not
+                  (RunConfig.equal_snapshot state.config_snapshot new_snapshot)
+              then (
+                state.pipeline <- create_reactive_pipeline ();
+                state.config_snapshot <- new_snapshot);
               Log_.Color.setup ();
               Timing.enabled := !Cli.timing;
               Reactive.set_debug !Cli.timing;
@@ -357,18 +376,18 @@ Examples:
               (* Match direct CLI output (a leading newline before the JSON array). *)
               Printf.printf "\n";
               EmitJson.start ();
-              state.run_analysis ~dce_config:state.dce_config
-                ~cmtRoot:state.cmtRoot
-                ~reactive_collection:(Some state.reactive_collection)
-                ~reactive_merge:(Some state.reactive_merge)
-                ~reactive_liveness:(Some state.reactive_liveness)
-                ~reactive_solver:(Some state.reactive_solver) ~skip_file:None
+              let p = state.pipeline in
+              state.run_analysis ~dce_config:p.dce_config ~cmtRoot:state.cmtRoot
+                ~reactive_collection:(Some p.reactive_collection)
+                ~reactive_merge:(Some p.reactive_merge)
+                ~reactive_liveness:(Some p.reactive_liveness)
+                ~reactive_solver:(Some p.reactive_solver) ~skip_file:None
                 ~file_stats ();
               issue_count := Log_.Stats.get_issue_count ();
-              let d, l = ReactiveSolver.stats ~t:state.reactive_solver in
+              let d, l = ReactiveSolver.stats ~t:p.reactive_solver in
               dead_count := d;
               live_count := l;
-              Log_.Stats.report ~config:state.dce_config;
+              Log_.Stats.report ~config:p.dce_config;
               Log_.Stats.clear ();
               EmitJson.finish ())
           |> response_of_result)

analysis/reanalyze/src/RunConfig.ml

@@ -21,6 +21,14 @@ let runConfig =
     unsuppress = [];
   }
 
+let reset () =
+  runConfig.dce <- false;
+  runConfig.exception_ <- false;
+  runConfig.suppress <- [];
+  runConfig.termination <- false;
+  runConfig.transitive <- false;
+  runConfig.unsuppress <- []
+
 let all () =
   runConfig.dce <- true;
   runConfig.exception_ <- true;
@@ -31,3 +39,24 @@ let exception_ () = runConfig.exception_ <- true
 let termination () = runConfig.termination <- true
 
 let transitive b = runConfig.transitive <- b
+
+type snapshot = {
+  dce: bool;
+  exception_: bool;
+  suppress: string list;
+  termination: bool;
+  transitive: bool;
+  unsuppress: string list;
+}
+
+let snapshot () =
+  {
+    dce = runConfig.dce;
+    exception_ = runConfig.exception_;
+    suppress = runConfig.suppress;
+    termination = runConfig.termination;
+    transitive = runConfig.transitive;
+    unsuppress = runConfig.unsuppress;
+  }
+
+let equal_snapshot (a : snapshot) (b : snapshot) = a = b

tests/analysis_tests/tests-reanalyze/deadcode/test-reactive-server.sh

@@ -58,7 +58,9 @@ time_end() {
 }
 
 BACKUP_FILE="/tmp/reactive-test-backup.$$"
+CONFIG_BACKUP_FILE="/tmp/reactive-test-config-backup.$$"
 DEFAULT_SOCKET_FILE=""
+CONFIG_FILE=""
 
 # Cleanup function
 cleanup() {
@@ -67,6 +69,11 @@ cleanup() {
     cp "$BACKUP_FILE" "$TEST_FILE"
     rm -f "$BACKUP_FILE"
   fi
+  # Restore config file if backup exists
+  if [[ -n "$CONFIG_FILE" && -f "$CONFIG_BACKUP_FILE" ]]; then
+    cp "$CONFIG_BACKUP_FILE" "$CONFIG_FILE"
+    rm -f "$CONFIG_BACKUP_FILE"
+  fi
   # Stop server if running
   if [[ -n "$SERVER_PID" ]] && kill -0 "$SERVER_PID" 2>/dev/null; then
     kill "$SERVER_PID" 2>/dev/null || true
@@ -190,6 +197,12 @@ configure_project() {
     log_error "Could not find test file for project: $project_name"
     exit 1
   fi
+
+  CONFIG_FILE="$PROJECT_DIR/rescript.json"
+  if [[ ! -f "$CONFIG_FILE" ]]; then
+    log_error "Could not find config file: $CONFIG_FILE"
+    exit 1
+  fi
 }
 
 configure_project
@@ -214,6 +227,7 @@ time_end "initial_build"
 
 # Backup the test file
 cp "$TEST_FILE" "$BACKUP_FILE"
+cp "$CONFIG_FILE" "$CONFIG_BACKUP_FILE"
 
 # Start the server
 start_server() {
@@ -332,6 +346,24 @@ PY
   time_end "json_compare"
 }
 
+set_config_suppress_all() {
+  python3 - <<PY
+import json
+
+path = "$CONFIG_FILE"
+with open(path) as f:
+    cfg = json.load(f)
+
+reanalyze = cfg.setdefault("reanalyze", {})
+reanalyze["suppress"] = ["src"]
+reanalyze["unsuppress"] = []
+
+with open(path, "w") as f:
+    json.dump(cfg, f, indent=2)
+    f.write("\\n")
+PY
+}
+
 # Add an unused value to the test file (creates +1 dead code warning)
 add_unused_value() {
   log_verbose "Adding unused value to $TEST_FILE"
@@ -487,6 +519,42 @@ run_scenario_make_live() {
   return 0
 }
 
+run_scenario_config_change() {
+  local baseline_count="$1"
+  local server_after="/tmp/reanalyze-after-config-server-$$.json"
+  local server_restored="/tmp/reanalyze-restored-config-server-$$.json"
+
+  log_edit "Updating rescript.json (reanalyze.suppress=[\"src\"])..."
+  set_config_suppress_all
+
+  log_reactive "Analyzing after config change..."
+  send_request "$server_after" "incremental"
+  local suppressed_count
+  suppressed_count=$(count_issues "$server_after")
+  if [[ "$suppressed_count" -ne 0 ]]; then
+    log_error "Expected 0 issues after suppressing src via config, got $suppressed_count"
+    rm -f "$server_after" "$server_restored"
+    return 1
+  fi
+
+  cp "$CONFIG_BACKUP_FILE" "$CONFIG_FILE"
+
+  log_reactive "Analyzing after config restore..."
+  send_request "$server_restored" "incremental"
+
+  local restored_count
+  restored_count=$(count_issues "$server_restored")
+  if [[ "$restored_count" -ne "$baseline_count" ]]; then
+    log_error "Expected $baseline_count issues after restoring config, got $restored_count"
+    rm -f "$server_after" "$server_restored"
+    return 1
+  fi
+
+  log "✓ Config change invalidates/recomputes server cache correctly"
+  rm -f "$server_after" "$server_restored"
+  return 0
+}
+
 # Run one benchmark iteration
 run_iteration() {
   local iter="$1"
@@ -539,6 +607,14 @@ main() {
   baseline_count=$(count_issues "$baseline_file")
   log "Baseline: $baseline_count issues"
   log ""
+
+  if ! run_scenario_config_change "$baseline_count"; then
+    log_error "Config-change scenario failed"
+    stop_server
+    rm -f "$baseline_file"
+    exit 1
+  fi
+  log ""
 
   #-----------------------------------------
   # BENCHMARK PHASE: Edit → Rebuild → Measure
@@ -627,4 +703,3 @@ main() {
 }
 
 main
-