Bump SnakeYAML and Expose Parse Options

project.clj

@@ -11,6 +11,6 @@
   :java-source-paths ["src/java"]
   :javac-options ["-target" "1.7" "-source" "1.7" "-Xlint:-options"]
   :dependencies
-  [[org.yaml/snakeyaml "1.25"]
+  [[org.yaml/snakeyaml "1.26"]
    [org.flatland/ordered "1.5.9"]]
   :profiles {:provided {:dependencies [[org.clojure/clojure "1.10.1"]]}})

src/clojure/clj_yaml/core.clj

@@ -1,7 +1,7 @@
 (ns clj-yaml.core
   (:require [flatland.ordered.map :refer (ordered-map)]
             [flatland.ordered.set :refer (ordered-set)])
-  (:import (org.yaml.snakeyaml Yaml DumperOptions DumperOptions$FlowStyle)
+  (:import (org.yaml.snakeyaml Yaml DumperOptions DumperOptions$FlowStyle LoaderOptions)
            (org.yaml.snakeyaml.constructor Constructor SafeConstructor BaseConstructor)
            (org.yaml.snakeyaml.representer Representer)
            (org.yaml.snakeyaml.error Mark)
@@ -27,17 +27,37 @@
   (doto (default-dumper-options)
     (.setDefaultFlowStyle (flow-styles flow-style))))
 
+(defn ^LoaderOptions default-loader-options
+  []
+  (LoaderOptions.))
+
+(defn ^LoaderOptions make-loader-options
+  [& {:keys [max-aliases-for-collections allow-recursive-keys]}]
+  (let [loader (default-loader-options)]
+    (when max-aliases-for-collections
+      (.setMaxAliasesForCollections loader max-aliases-for-collections))
+    (when allow-recursive-keys
+      (.setAllowRecursiveKeys loader allow-recursive-keys))
+    loader))
+
 (defn ^Yaml make-yaml
   "Make a yaml encoder/decoder with some given options."
-  [& {:keys [dumper-options unsafe mark]}]
-  (let [^BaseConstructor constructor
-        (if unsafe (Constructor.)
-            (if mark (MarkedConstructor.) (SafeConstructor.)))
+  [& {:keys [dumper-options unsafe mark max-aliases-for-collections allow-recursive-keys]}]
+  (let [loader (make-loader-options :max-aliases-for-collections max-aliases-for-collections
+                                    :allow-recursive-keys allow-recursive-keys)
+        ^BaseConstructor constructor
+        (if unsafe (Constructor. loader)
+            (if mark
+              ;; construct2ndStep isn't implemented by MarkedConstructor,
+              ;; causing an exception to be thrown before loader options are
+              ;; used
+              (MarkedConstructor.)
+              (SafeConstructor. loader)))
         ;; TODO: unsafe marked constructor
         dumper (if dumper-options
                  (make-dumper-options :flow-style (:flow-style dumper-options))
                  (default-dumper-options))]
-    (Yaml. constructor (Representer.) dumper)))
+    (Yaml. constructor (Representer.) dumper loader)))
 
 (defrecord Marked
   [start end unmark])
@@ -126,5 +146,9 @@
          (encode data)))
 
 (defn parse-string
-  [^String string & {:keys [unsafe mark keywords] :or {keywords true}}]
-  (decode (.load (make-yaml :unsafe unsafe :mark mark) string) keywords))
+  [^String string & {:keys [unsafe mark keywords max-aliases-for-collections allow-recursive-keys] :or {keywords true}}]
+  (decode (.load (make-yaml :unsafe unsafe
+                            :mark mark
+                            :max-aliases-for-collections max-aliases-for-collections
+                            :allow-recursive-keys allow-recursive-keys)
+                 string) keywords))

test/clj_yaml/core_test.clj

@@ -2,7 +2,8 @@
   (:require [clojure.test :refer (deftest testing is)]
             [clojure.string :as string]
             [clj-yaml.core :refer [parse-string unmark generate-string]])
-  (:import [java.util Date]))
+  (:import [java.util Date]
+           (org.yaml.snakeyaml.error YAMLException)))
 
 (def nested-hash-yaml
   "root:\n  childa: a\n  childb: \n    grandchild: \n      greatgrandchild: bar\n")
@@ -199,3 +200,23 @@ the-bin: !!binary 0101")
   (testing "emoji in comments are OK too"
     (let [yaml "# 💣 emoji in a comment\n42"]
       (is (= 42 (parse-string yaml))))))
+
+(def too-many-aliases
+  (->> (range 51)
+       (map #(str "b" % ": *a"))
+       (cons "a: &a [\"a\",\"a\"]")
+       (string/join "\n")))
+
+(deftest max-aliases-for-collections-works
+  (is (thrown-with-msg? YAMLException #"Number of aliases" (parse-string too-many-aliases)))
+  (is (parse-string too-many-aliases :max-aliases-for-collections 51)))
+
+(def recursive-yaml "
+---
+&A
+- *A: *A
+")
+
+(deftest allow-recursive-works
+  (is (thrown-with-msg? YAMLException #"Recursive" (parse-string recursive-yaml)))
+  (is (parse-string recursive-yaml :allow-recursive-keys true)))