Optimize member-info

Its usage of laziness could likely mean that more objects would be retained than necessary, causing OOMs in constrainted environments.

Reported in https://clojurians.slack.com/archives/C0617A8PQ/p1645530472596039

Author: vemv

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## master (unreleased)
 
+* Guard against OOMs in `orchard.java/member-info`.
+
 ## 0.9.1 (2022-01-17)
 
 ### Bugs fixed

src/orchard/java.clj

@@ -268,11 +268,16 @@
   implemention. If the member is an instance member, `this` is prepended to its
   arglists."
   [class member]
-  (let [c (->> (class-info class)
-               (iterate (comp class-info :super))
-               (take-while identity)
-               (filter #(get-in % [:members member]))
-               (first))]
+  (let [c
+        ;; NOTE: the following code uses `loop` to avoid retaining more objects in memory than necessary.
+        ;; `class-info` calls can be expensive given the JavaDoc parsing they can perform.
+        (loop [next-class class]
+          (let [{:keys [super] :as c-i} (class-info next-class)
+                v (get-in c-i [:members member])]
+            (cond
+              v c-i
+              (not super) nil
+              :else (recur super))))]
     (when-let [m (get-in c [:members member])]
       (let [m* (first (sort-by :line (vals m)))
             static? (or (:static (:modifiers m*)) (= class member))

test/orchard/java_test.clj

@@ -2,6 +2,7 @@
   (:require
    [clojure.java.io :as io]
    [clojure.java.javadoc :as javadoc]
+   [clojure.string :as string]
    [clojure.test :refer [are deftest is testing]]
    [orchard.java :refer [cache class-info class-info* javadoc-url jdk-tools member-info resolve-class resolve-javadoc-path resolve-member resolve-symbol resolve-type source-info]]
    [orchard.misc :as misc]
@@ -130,7 +131,9 @@
         (testing "implemented on immediate superclass"
           (is (not= 'java.lang.Object (:class m6))))
         (testing "implemented on ancestor superclass"
-          (is (not= 'java.lang.Object (:class m7))))))))
+          (is (not= 'java.lang.Object (:class m7)))
+          (is (-> m6 :doc (string/starts-with? "Called by the garbage collector on an object when garbage collection "))
+              "Contains doc that is clearly defined in Object (the superclass)"))))))
 
 (deftest arglists-test
   (let [+this (comp #{'this} first)]