Ensure ex-data is always presentable (#617)

Prevent browser from crashing when the file watcher is started with `:show-filter-fn` and a namespace throws exceptions

Author: zampino

CHANGELOG.md

@@ -31,6 +31,8 @@ Changes can be:
 
 * 🐜 Fix blank screen caused by react unmounting when an exception occurs during `clerk/show!`, fixes [#586](https://github.com/nextjournal/clerk/issues/586) @elken
 
+* 🐜 Fix browser crashing when file watcher is used with `:show-filter-fn` option in notebooks with exceptions, fixes [#616](https://github.com/nextjournal/clerk/issues/616).
+
 * 🐜 Make edn transmission resilient to symbols and keywords containing multiple slashes like `foo/bar/baz`. Those can be read by `read-string` but not in ClojureScript which is based on `tools.reader`.
 
 * 🐞 Fix `:nextjournal.clerk/page-size` option throwing when set on string values, fixes [#584][https://github.com/nextjournal/clerk/issues/584]

notebooks/pagination.clj

@@ -93,3 +93,10 @@
 
 ;; Images are displayed correctly when expanding elided data:
 (concat (range 20) (list (clerk/image "trees.png")))
+
+;; Elisions in exception data are fetched correctly:
+(ex-info "Boink 💥"
+         {:boom (fn boom [x] x)
+          :range (range 30)
+          :image (clerk/image "trees.png")}
+         (RuntimeException. "no way"))

src/nextjournal/clerk.clj

@@ -75,7 +75,7 @@
          (println (str "Clerk evaluated '" file "' in " time-ms "ms."))
          (webserver/update-doc! result))
        (catch Exception e
-         (webserver/update-doc! (assoc (-> e ex-data ::doc) :error e))
+         (webserver/update-doc! (-> e ex-data ::doc (assoc :error e) (update :ns #(or % (find-ns 'user)))))
          (throw e))))))
 
 #_(show! "notebooks/exec_status.clj")

src/nextjournal/clerk/paths.clj

@@ -2,8 +2,7 @@
   "Clerk's paths expansion and paths-fn handling."
   (:require [babashka.fs :as fs]
             [clojure.edn :as edn]
-            [clojure.string :as str]
-            [nextjournal.clerk.git :as git])
+            [clojure.string :as str])
   (:import [java.net URL]))
 
 (defn ^:private ensure-not-empty [build-opts {:as opts :keys [error expanded-paths]}]
@@ -123,19 +122,6 @@
 #_(index-paths {:paths ["CHANGELOG.md"]})
 #_(index-paths {:paths-fn "boom"})
 
-(defn process-paths [{:as opts :keys [paths paths-fn index]}]
-  (merge (if (or paths paths-fn index)
-           (expand-paths opts)
-           opts)
-         (git/read-git-attrs)))
-
-#_(process-paths {:paths ["notebooks/rule_30.clj"]})
-#_(process-paths {:paths ["notebooks/rule_30.clj"] :index "notebooks/links.md"})
-#_(process-paths {:paths ["notebooks/no_rule_30.clj"]})
-#_(v/route-index? (process-paths @!server))
-#_(route-index (process-paths @!server) "")
-
-
 (defn path-in-cwd
   "Turns `file` into a unixified (forward slashed) path if the is in the cwd,
   returns `nil` otherwise."

src/nextjournal/clerk/render.cljs

@@ -480,7 +480,7 @@
      [:div.overflow-x-auto.overflow-y-hidden.w-full.shadow.sticky-table-header
       [:table.text-xs.sans-serif.text-gray-900.dark:text-white.not-prose {:ref !table-clone-ref :style {:margin 0}}]]]))
 
-(defn throwable-view [{:keys [via trace]}]
+(defn throwable-view [{:keys [via trace]} opts]
   [:div.bg-white.max-w-6xl.mx-auto.text-xs.monospace.not-prose
    (into
     [:div]
@@ -491,7 +491,7 @@
           [:div.font-bold "Unhandled " type])
         [:div.font-bold.mt-1 message]
         (when data
-          [:div.mt-1 [inspect (viewer/inspect-wrapped-values data)]])])
+          [:div.mt-1 [inspect-presented opts data]])])
      via))
    [:div.py-6.overflow-x-auto
     [:table.w-full
@@ -503,10 +503,10 @@
                    [:td.py-1.pr-6 call]]))
            trace)]]])
 
-(defn render-throwable [ex]
+(defn render-throwable [ex opts]
   (if (or (:stack ex) (instance? js/Error ex))
     [error-view ex]
-    [throwable-view ex]))
+    [throwable-view ex opts]))
 
 (defn render-tagged-value
   ([tag value] (render-tagged-value {:space? true} tag value))
@@ -560,16 +560,30 @@
 
 #_(show-panel :test {:content [:div "Test"] :width 600 :height 600})
 
+(defn with-fetch-fn [{:nextjournal/keys [presented blob-id]} body-fn]
+  ;; TODO: unify with result-viewer
+  (let [!presented-value (hooks/use-state presented)
+        body-fn* (hooks/use-callback body-fn)]
+    [view-context/provide
+     {:fetch-fn (fn [elision]
+                  (.then (fetch! {:blob-id blob-id} elision)
+                         (fn [more] (swap! !presented-value viewer/merge-presentations more elision))))}
+     [body-fn* @!presented-value]]))
+
 (defn root []
   [:<>
    [:div.fixed.w-full.z-20.top-0.left-0.w-full
     (when-let [status (:nextjournal.clerk.sci-env/connection-status @!doc)]
       [connection-status status])
     (when-let [status (:status @!doc)]
       [exec-status status])]
-   (when-let [error (get-in @!doc [:nextjournal/value :error])]
-     [:div.fixed.top-0.left-0.w-full.h-full
-      [inspect-presented error]])
+   (when-let [{:as wrapped-value :nextjournal/keys [blob-id]} (get-in @!doc [:nextjournal/value :error])]
+     (let [!expanded-at (r/atom {})]
+       ^{:key blob-id}
+       [with-fetch-fn wrapped-value
+        (fn [presented-value]
+          [:div.fixed.top-0.left-0.w-full.h-full
+           [inspect-presented {:!expanded-at !expanded-at} presented-value]])]))
    (when (:nextjournal/value @!doc)
      [inspect-presented @!doc])
    (into [:<>]

src/nextjournal/clerk/viewer.cljc

@@ -901,12 +901,35 @@
    :transform-fn (comp #?(:cljs var->symbol :clj symbol) ->value)
    :render-fn '(fn [x] [:span.inspected-value [:span.cmt-meta "#'" (str x)]])})
 
+(defn ->opts [wrapped-value]
+  (select-keys wrapped-value [:nextjournal/budget :nextjournal/css-class :nextjournal/width :nextjournal/render-opts
+                              :nextjournal/render-evaluator
+                              :!budget :store!-wrapped-value :present-elision-fn :path :offset]))
+
+(defn inherit-opts [{:as wrapped-value :nextjournal/keys [viewers]} value path-segment]
+  (-> (ensure-wrapped-with-viewers viewers value)
+      (merge (select-keys (->opts wrapped-value) [:!budget :store!-wrapped-value :present-elision-fn :nextjournal/budget :path]))
+      (update :path (fnil conj []) path-segment)))
+
+(defn present-ex-data [parent throwable-map]
+  (let [present-child (fn [idx data] (present (inherit-opts parent data idx)))]
+    (-> throwable-map
+        (update-if :data (partial present-child 0))
+        (update-if :via (fn [exs]
+                          (mapv (fn [i ex] (update-if ex :data (partial present-child (inc i))))
+                                (range (count exs))
+                                exs))))))
+
 (def throwable-viewer
   {:name `throwable-viewer
    :render-fn 'nextjournal.clerk.render/render-throwable
    :pred (fn [e] (instance? #?(:clj Throwable :cljs js/Error) e))
-   :transform-fn (comp mark-presented (update-val (comp demunge-ex-data
-                                                        datafy/datafy)))})
+   :transform-fn (fn [wrapped-value]
+                   (-> wrapped-value
+                       mark-presented
+                       (update :nextjournal/value (comp demunge-ex-data
+                                                        (partial present-ex-data wrapped-value)
+                                                        datafy/datafy))))})
 
 #?(:clj
    (defn buffered-image->bytes [^BufferedImage image]
@@ -957,17 +980,6 @@
 (def mathjax-viewer
   {:name `mathjax-viewer :render-fn 'nextjournal.clerk.render/render-mathjax :transform-fn mark-presented})
 
-(defn ->opts [wrapped-value]
-  (select-keys wrapped-value [:nextjournal/budget :nextjournal/css-class :nextjournal/width :nextjournal/render-opts
-                              :nextjournal/render-evaluator
-                              :!budget :store!-wrapped-value :present-elision-fn :path :offset]))
-
-(defn inherit-opts [{:as wrapped-value :nextjournal/keys [viewers]} value path-segment]
-  (-> (ensure-wrapped-with-viewers viewers value)
-      (merge (select-keys (->opts wrapped-value) [:!budget :store!-wrapped-value :present-elision-fn :nextjournal/budget :path]))
-      (update :path (fnil conj []) path-segment)))
-
-
 (defn transform-html [{:as wrapped-value :keys [path]}]
   (let [!path-idx (atom -1)]
     (update wrapped-value
@@ -1254,6 +1266,10 @@
    :transform-fn transform-toc
    :render-fn 'nextjournal.clerk.render.navbar/render-items})
 
+(defn present-error [error]
+  {:nextjournal/presented (present error)
+   :nextjournal/blob-id (str (gensym "error"))})
+
 (defn process-blocks [viewers {:as doc :keys [ns]}]
   (-> doc
       (assoc :atom-var-name->state (atom-var-name->state doc))
@@ -1278,7 +1294,7 @@
                     :toc-visibility
                     :header
                     :footer])
-      (update-if :error present)
+      (update-if :error present-error)
       (assoc :sidenotes? (boolean (seq (:footnotes doc))))
       #?(:clj (cond-> ns (assoc :scope (datafy-scope ns))))))
 

src/nextjournal/clerk/webserver.clj

@@ -7,6 +7,7 @@
             [clojure.string :as str]
             [editscript.core :as editscript]
             [nextjournal.clerk.config :as config]
+            [nextjournal.clerk.git :as git]
             [nextjournal.clerk.paths :as paths]
             [nextjournal.clerk.view :as view]
             [nextjournal.clerk.viewer :as v]
@@ -173,10 +174,21 @@
 
 (declare present+reset!)
 
-(defn get-build-opts []
-  (paths/process-paths @!server))
+(defn get-build-opts
+  ([] (get-build-opts @!server))
+  ([{:as opts :keys [paths paths-fn index]}]
+   (merge (git/read-git-attrs)
+          (if (or paths paths-fn index)
+            (paths/expand-paths opts)
+            opts))))
 
 #_(get-build-opts)
+#_(get-build-opts {:paths ["notebooks/rule_30.clj"]})
+#_(get-build-opts {:paths ["notebooks/rule_30.clj"] :index "notebooks/links.md"})
+#_(get-build-opts {:paths ["notebooks/no_rule_30.clj"]})
+#_(v/route-index? (get-build-opts @!server))
+#_(route-index (get-build-opts @!server) "")
+#_(route-index (get-build-opts {:index "notebooks/rule_30.clj"}) "")
 
 (defn ->nav-path [file-or-ns]
   (cond (or (= 'nextjournal.clerk.index file-or-ns)
@@ -247,7 +259,7 @@
 (defn prefetch-request? [req] (= "prefetch" (-> req :headers (get "purpose"))))
 
 (defn serve-notebook [{:as req :keys [uri]}]
-  (let [opts (paths/process-paths @!server)
+  (let [opts (get-build-opts)
         nav-path (maybe-route-index opts (subs uri 1))]
     (cond
       (prefetch-request? req)

test/nextjournal/clerk/viewer_test.clj

@@ -132,6 +132,28 @@
     (is (= :full
            (:nextjournal/width (v/apply-viewers (v/table {:nextjournal.clerk/width :full} {:a [1] :b [2] :c [3]})))))))
 
+(deftest present-exceptions
+  (testing "can represent ex-data in a readable way"
+    (binding [*data-readers* v/data-readers]
+
+      (is (-> (eval-test/eval+extract-doc-blocks "(ex-info \"💥\"  {:foo 123 :boom (fn boom [x] x)})")
+              second :nextjournal/value :nextjournal/presented
+              v/->edn
+              read-string))
+
+      (is (-> (eval-test/eval+extract-doc-blocks "(ex-info \"💥\"  {:foo 123 :boom (fn boom [x] x)} (RuntimeException. \"no way\"))")
+              second :nextjournal/value :nextjournal/presented
+              v/->edn
+              read-string)))))
+
+(deftest present-functions
+  (testing "can represent functions in a readable way"
+    (binding [*data-readers* v/data-readers]
+      (is (-> (eval-test/eval+extract-doc-blocks "(fn boom [x] x)")
+              second :nextjournal/value :nextjournal/presented
+              v/->edn
+              read-string)))))
+
 (deftest datafy-scope
   (is (= (ns-name *ns*)
          (v/datafy-scope *ns*)