Add extra error message context for fn executions

src/clj/fluree/db/query/exec/eval.cljc

@@ -398,7 +398,7 @@
                       allowed-scalar-fns)]
     (if (contains? allowed-fns sym)
       (let [qsym (get qualified-symbols sym sym)]
-        (log/debug "qualified symbol" sym "as" qsym)
+        (log/trace "qualified symbol" sym "as" qsym)
         qsym)
       (let [err-msg (if (and (not allow-aggregates?)
                              (contains? allowed-aggregate-fns sym))
@@ -442,7 +442,7 @@
                            (log/trace "fn bindings:" (quote ~bdg))
                            (let ~bdg
                              ~qualified-code))]
-     (log/debug "compiled fn:" fn-code)
+     (log/trace "compiled fn:" fn-code)
      (eval fn-code))))
 
 (defn compile-filter

src/clj/fluree/db/query/exec/where.cljc

@@ -1,6 +1,7 @@
 (ns fluree.db.query.exec.where
   (:require [fluree.db.query.range :as query-range]
             [clojure.core.async :as async :refer [>! go]]
+            [clojure.string :as str]
             [fluree.db.flake :as flake]
             [fluree.db.fuel :as fuel]
             [fluree.db.index :as index]
@@ -425,16 +426,31 @@
         (-match-class active-graph fuel-tracker solution triple error-ch)))
     nil-channel))
 
+(defn filter-exception
+  "Reformats raw filter exception to try to provide more useful feedback."
+  [e solution f]
+  (let [fn-str (->> f meta :fns (str/join " "))
+        ex-msg (or (ex-message e)
+                   ;; note: NullPointerException is common but has no ex-message, create one
+                   (let [ex-type (str (type e))] ;; attempt to make JS compatible
+                     (if (= ex-type "class java.lang.NullPointerException")
+                       "Variable has null value, cannot apply filter"
+                       "Unknown error")))
+        e*     (ex-info (str "Exception in statement '[filter " fn-str "]': " ex-msg)
+                        {:status 400
+                         :error  :db/invalid-query}
+                        e)]
+    (log/warn (ex-message e*))
+    e*))
+
 (defmethod match-pattern :filter
   [_ds _fuel-tracker solution pattern error-ch]
   (go
-    (try*
-      (let [f (pattern-data pattern)]
-        (when (f solution)
-          solution))
-      (catch* e
-              (log/error e "Error applying filter")
-              (>! error-ch e)))))
+    (let [f (pattern-data pattern)]
+      (try*
+       (when (f solution)
+         solution)
+       (catch* e (>! error-ch (filter-exception e solution f)))))))
 
 (defn with-constraint
   "Return a channel of all solutions from the data set `ds` that extend from the

src/clj/fluree/db/query/fql/parse.cljc

@@ -385,7 +385,7 @@
                (map parse-code)
                (map eval/compile)
                (apply every-pred))]
-    [(where/->pattern :filter f)]))
+    [(where/->pattern :filter (with-meta f {:fns codes}))]))
 
 (defmethod parse-pattern :union
   [[_ & unions] vars context]

src/clj/fluree/db/query/range.cljc

@@ -95,6 +95,19 @@
   [f]
   (= f ::unauthorized))
 
+(defn authorize-flake-exception
+  "Wraps upstream exception and logs out a warning message"
+  [e db flake]
+  (let [e* (ex-info (str "Policy exception authorizing Flake in "
+                         (:alias db) "?t=" (:t db)
+                         ". " (ex-message e))
+                    {:error  :db/policy-exception
+                     :status 400
+                     :flake  flake}
+                    e)]
+    (log/warn (ex-message e*))
+    e*))
+
 (defn authorize-flake
   [db error-ch flake]
   (go
@@ -103,10 +116,7 @@
             flake
             ::unauthorized)
           (catch* e
-                  (log/error e
-                             "Error authorizing flake in ledger"
-                             (select-keys db [:network :ledger-id :t]))
-                  (>! error-ch e)))))
+                  (>! error-ch (authorize-flake-exception e db flake))))))
 
 (defn authorize-flakes
   "Authorize each flake in the supplied `flakes` collection asynchronously,