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edn: clean exception for an unknown reader tag

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clojure.edn's __read-tagged seam called (empty-pmap) — applying the empty-pmap
VALUE as a procedure — so an unknown tag (e.g. #object[...] from a JVM-printed
object, or any unregistered #foo) crashed the Chez VM with "attempt to apply
non-procedure" and surfaced a malformed condition (class :object, nil message)
instead of a catchable error.

Throw a clean ex-info naming the tag, matching the JVM's "No reader function
for tag <tag>". A reader port over edn (transit-jolt's read-conformance skip
path, aero, etc.) now catches a real exception instead of aborting.

clojure.core/read-string stays lenient (returns the tagged form) so clojure.edn
can apply :readers / :default before falling through to this throw.
This commit is contained in:
Yogthos 2026-06-24 23:09:07 -04:00
parent 9c48440a43
commit fb2749ac4c
2 changed files with 10 additions and 2 deletions
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3
test/chez/corpus.edn
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@ -3063,4 +3063,7 @@
{:suite "interop / java.io streams" :label "BufferedReader over StringReader readLine" :expected "[\"a\" \"b\" nil]" :actual "(let [r (java.io.BufferedReader. (java.io.StringReader. \"a\\nb\\n\"))] [(.readLine r) (.readLine r) (.readLine r)])"}
{:suite "interop / java.io streams" :label "instance? InputStream" :expected "true" :actual "(instance? java.io.InputStream (java.io.ByteArrayInputStream. (.getBytes \"x\")))"}
{:suite "interop / java.io streams" :label "FileOutputStream then FileInputStream round-trip" :expected "90" :actual "(let [f (java.io.File/createTempFile \"jc\" \".t\") o (java.io.FileOutputStream. f)] (.write o (byte-array [90])) (.close o) (let [in (java.io.FileInputStream. f) b (.read in)] (.close in) (.delete f) b))"}
{:suite "clojure.edn / unknown tags" :label "unknown tag throws naming the tag" :expected "\"No reader function for tag foobar\"" :actual "(do (require (quote [clojure.edn :as e1])) (try (e1/read-string \"#foobar 1\") (catch Exception e (ex-message e))))"}
{:suite "clojure.edn / unknown tags" :label "object tag throws naming the tag" :expected "\"No reader function for tag object\"" :actual "(do (require (quote [clojure.edn :as e2])) (try (e2/read-string \"#object [1 2 3]\") (catch Exception e (ex-message e))))"}
{:suite "clojure.edn / unknown tags" :label ":default opt handles an unknown tag" :expected "[\"foobar\" 9]" :actual "(do (require (quote [clojure.edn :as e3])) (e3/read-string {:default (fn [t v] [(name t) v])} \"#foobar 9\"))"}
]