fix: pin_module_config no longer silently destroys pipelines (audit wave 3)

NEWS.md

@@ -39,6 +39,10 @@ First development changelog. dsprrr is experimental; the API may change.
   `refine(best_of_n(mod))`) compose their ids cleanly instead of crashing with
   a duplicate-argument error (#dsprrr-pcd, #dsprrr-wx6).
 
+* `pin_module_config()` now errors clearly for pipelines and other unsupported
+  module types instead of silently serialising them as an empty `PredictModule`
+  and dropping every step on restore (#dsprrr-07u).
+
 ## Internal
 
 * Tests now isolate the on-disk cache to a temporary directory, so running

R/orchestration.R

@@ -159,6 +159,15 @@ restore_module_config <- function(config, signature = NULL) {
 }
 
 serialize_module_config_v2 <- function(module) {
+  if (inherits(module, "PipelineModule")) {
+    cli::cli_abort(c(
+      "Pipeline persistence is not yet supported",
+      "x" = "{.fn pin_module_config} cannot serialise a {.cls PipelineModule}",
+      "i" = "Persisting it here would silently drop every step and its demos",
+      "i" = "Pin each step module individually, or rebuild the pipeline from source"
+    ))
+  }
+
   kind <- module_kind(module)
   supported <- c("predict", "react", "chain_of_thought", "multichain")
   if (!kind %in% supported) {

R/run.R

@@ -292,7 +292,11 @@ module_kind <- function(module) {
       "ReactModule" = "react",
       "MultiChainComparisonModule" = "multichain",
       "PredictModule" = "predict",
-      "predict"
+      # Fall back to the actual class name rather than silently claiming
+      # "predict" -- otherwise unsupported module types (pipelines, ensembles,
+      # RAG, ...) pass the persistence allow-list and serialize as a bare
+      # PredictModule, losing all of their structure.
+      class(module)[1]
     )
 }
 

tests/testthat/test-orchestration.R

@@ -465,3 +465,20 @@ test_that("module config round-trips correctly", {
   expect_true(restored$is_compiled())
   expect_equal(restored$state$best_score, 0.92)
 })
+
+test_that("pin_module_config refuses to silently destroy pipelines (dsprrr-07u)", {
+  skip_if_not_installed("pins")
+
+  m1 <- module(signature("question -> thought"), type = "predict")
+  m2 <- module(signature("thought -> answer"), type = "predict")
+  pipe <- pipeline(m1, m2)
+  board <- pins::board_temp()
+
+  # Regression: module_kind() collapsed unknown classes to "predict", so a
+  # pipeline pinned without error and restored as a single empty PredictModule,
+  # silently losing every step and its bootstrapped demos.
+  expect_error(
+    pin_module_config(board, "pipe", pipe),
+    "[Pp]ipeline"
+  )
+})