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with-meta on a list/seq returns a fresh copy, not the original

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meta-copy keyed metadata on the SAME cseq/lazyseq object (the else branch), so
(with-meta xs m) mutated the original list in place — Clojure's PersistentList
is immutable and withMeta returns a new list. (with-meta xs {:k xs}) thus built
a self-referential cycle (the list's metadata pointed at the list), which looped
*print-meta* printing forever — the root of aero's meta-preservation hang. Now
copies the cseq/lazyseq node like the other collections. aero suite completes:
58/0/1 (was hanging).
This commit is contained in:
Yogthos 2026-06-27 01:10:34 -04:00
parent afc733a439
commit 3491312ca1
2 changed files with 13 additions and 1 deletions
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4
test/chez/corpus.edn
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@ -3308,4 +3308,8 @@
{:suite "reader / metadata" :label "an empty list in metadata reads as a value" :expected "true" :actual "(= () (:e (meta (read-string \"^{:e ()} [1]\"))))"}
{:suite "edn / readers in collections" :label "a :default tag reader applies inside a set" :expected "true" :actual "(= #{[:t 1]} (clojure.edn/read-string {:default (fn [t v] [:t v])} \"#{#foo 1}\"))"}
{:suite "edn / readers in collections" :label "a registered reader applies inside a set" :expected "true" :actual "(= #{6} (clojure.edn/read-string {:readers {(quote x) (fn [v] (* v 2))}} \"#{#x 3}\"))"}
{:suite "metadata / immutability" :label "with-meta on a list does not mutate the original" :expected "true" :actual "(let [ds (list 1 2)] (with-meta ds {:k 1}) (nil? (meta ds)))"}
{:suite "metadata / immutability" :label "with-meta on a list carries the metadata" :expected "true" :actual "(= {:k 1} (meta (with-meta (list 1) {:k 1})))"}
{:suite "metadata / immutability" :label "a meta-bearing list still equals the bare list" :expected "true" :actual "(let [ds (list 1)] (= ds (with-meta ds {:k 9})))"}
{:suite "metadata / immutability" :label "with-meta on a lazy seq carries metadata" :expected "true" :actual "(= {:k 5} (meta (with-meta (lazy-seq (list 1)) {:k 5})))"}
]