Red Team 2 — Consolidated Report

meme-clj v2.0.0 | 2026-04-02

Methodology: 50+ hypotheses tested via live nREPL + 5 deep-dive code analysis agents (tokenizer, parser, printer/formatter, rewrite/lang, CLI/runtime). Non-overlapping with Red Team 2026-04-01 and Magenta Team 2026-04-02.

Test baseline: 918 JVM + 771 CLJS + 11 meme example tests — all passing.

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Scoreboard

Severity	Count	Examples
HIGH	6	TRS #() corruption, double syntax-quote, #::{} empty ns, metadata CCE, EDN code exec, TRS :: divergence
MEDIUM	15	Symbol/keyword splits, BOM, rewrite non-termination, surrogate chars, bare :, register! override, restore-bare-percent
LOW	14	Comments dropped, null bytes, Unicode control chars, number greedy scan, metadata flat rendering
INFO	5	clj->meme sugar loss, emit fallback, error message quality
Total	40

HIGH Findings (6)

H1. TRS #() semantic corruption

#(+(% 1)) → TRS emits #((+ % 1)) — extra parens make it call the return value as a function. Runtime ClassCastException. Classic/rewrite correctly emit #(+ % 1).

Location: src/meme/trs.cljc, src/meme/lang/meme_trs.cljc

H2. Double syntax-quote x `` wrong expansion

Clojure eval of x : `'redteam2/x` (namespace-qualified, one level of quoting). Meme eval of x: 'x (unqualified, wrong structure).

The inner backtick doesn't produce a proper nested expansion. Breaks macro-writing-macros that rely on ~~ ``x patterns.

Location: src/meme/parse/expander.cljc

H3. #::{} produces malformed keywords

Tokenizer's read-symbol-str consumes : as a symbol char after #:. Result: ns-name="", output {:/a 1} instead of current-namespace-qualified keywords. Clojure #::{} correctly resolves to current namespace.

Location: src/meme/scan/tokenizer.cljc:338-342, src/meme/parse/reader.cljc:517-520

H4. ^:foo 42 — raw ClassCastException

Metadata type check passes (keyword is valid metadata), but vary-meta on a number throws unhandled ClassCastException: Long cannot be cast to IObj. Missing metadatable? guard on the target before calling vary-meta.

Location: src/meme/parse/reader.cljc:431

H5. EDN lang loading = arbitrary code execution

--lang file.edn calls requiring-resolve on symbols in the EDN (loads namespaces from classpath) and slurp+eval on :run string paths. No sandboxing, no path validation, no allowlist.

Location: src/meme/lang.cljc:47-97, src/meme/runtime/cli.clj:77-83

H6. TRS ::keyword semantics differ from classic

TRS preserves ::foo verbatim in output; classic expands for deferred resolution. When Clojure output is read in a different namespace, ::foo resolves to the wrong namespace. Not covered by lang agreement tests.

Location: src/meme/trs.cljc, test/meme/trs_test.cljc:98-120

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MEDIUM Findings (15)

M1. foo/bar/baz parsed as two forms

Meme splits at first /, producing foo/bar + /baz. Clojure reads as one symbol foo/bar/baz. Silent mis-parse.

M2. :foo/bar/baz keyword split

Same pattern as M1 but for keywords. Silently splits at the second slash.

M3. foo/ trailing slash accepted

Meme accepts and emits foo/. Clojure rejects: "Invalid token: foo/". Produces invalid Clojure output.

M4. foo/1bar digit-starting name accepted

Meme accepts foo/1bar as a symbol. Clojure rejects — name part after / cannot start with a digit.

M5. #'foo(bar) → (var (foo bar)) → invalid Clojure

Meme parses #'foo(bar) as var-quote of a call → (var (foo bar)). Clojure's var only accepts symbols, not lists. Output: Syntax error compiling var.

M6. #'^:foo bar silently drops metadata

Meme: #'^:foo bar → (var bar) — metadata ^:foo is lost. Clojure preserves metadata on the var form.

M7. BOM marker corrupts Clojure output

Input file: UTF-8 BOM + f(x y). Output file hex: 28 EF BB BF 66 20 78 20 79 29 → (ﻯf x y). The BOM bytes appear inside the opening paren, producing invalid Clojure.

M8. Rewrite non-termination on size-increasing rules

Rule ?x → [?x ?x] causes infinite loop / timeout. The 100-iteration cycle detection is bypassed because each iteration produces a different (larger) form. Needs a size budget or output-size cap.

M9. anon-fn-depth volatile not decremented on error paths

anon-fn-depth incremented at line 541, decremented at line 557. Any error between corrupts the counter. Compare: sq-depth correctly uses try/finally.

Location: src/meme/parse/reader.cljc:537-567

M10. Surrogate char literals \uD800-\uDFFF accepted

resolve-char lacks the surrogate range check that already exists in parse-unicode-escape for strings. Meme accepts, Clojure throws UnsupportedOperationException.

Location: src/meme/parse/resolve.cljc:88-96

M11. Bare : lone colon accepted as keyword

Produces (keyword ""). Clojure rejects: "Invalid token: :".

M12. #:{:a 1} empty namespace accepted

Clojure: "Namespaced map must specify a namespace". Meme: silently produces {:/a 1}.

M13. s->m-rules guard drops non-symbol/non-keyword heads

Lists with nil, true, false, or number heads are not tagged as m-call. clj->meme-text emits (nil 1 2) S-expression syntax instead of valid meme nil(1 2).

Location: src/meme/rewrite/rules.cljc:12-19

M14. register! allows silently overriding built-in langs

(register! :meme-classic {...}) hijacks the default lang with no warning. Process-global state mutation. No name-collision check against built-ins.

Location: src/meme/lang.cljc:175-189

M15. restore-bare-percent doesn't recurse into maps/sets

normalize-bare-percent in forms.cljc recurses into maps and sets. restore-bare-percent in printer.cljc does not. Result: #(#{%}) roundtrips as #(#{%1}), violating syntactic transparency.

Location: src/meme/emit/printer.cljc:71-79

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LOW Findings (14)

ID	Finding
L1	TRS unexpanded syntax-quote — emits `(f ~x) instead of expanded seq/concat/list
L2	~x outside syntax-quote: classic errors, rewrite/trs accept — inconsistency
L3	Comment silently dropped by formatter — def(x ;; important\n 42) → def(x 42)
L4	Comment-only file produces empty output in to-clj
L5	Null byte consumed as whitespace — f(x\0y) → (f x y), silent data alteration
L6	Zero-width space (U+200B) absorbed into symbol names — invisible character attack vector
L7	RTL override (U+202E) accepted in symbols — display-level attack
L8	match-pattern returns nil for splice variable ?&args — silently fails to match
L9	read-number greedy: 1N.5 is one token (error), Clojure reads two forms. Same for 1-2, 1+2
L10	##foo accepts any symbol after ## — confusing "Invalid number" error vs Clojure's "Invalid token"
L11	\r-only line endings: all tokens report line 1 — sadvance! only increments on \newline
L12	Metadata maps always rendered flat — ^{:doc "...long..."} committed to string before layout engine
L13	flat/format-forms drops trailing file comments — canon handles them, flat does not
L14	match-seq with multiple splice variables is O(n^k) — k splice vars on n elements

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INFO Findings (5)

ID	Finding
I1	clj->meme loses reader sugar (', @, #()) — Clojure reader limitation, not meme bug
I2	Rewrite engine crash on non-seq input — raw IllegalArgumentException instead of structured error
I3	emit fallback to pr-str for AST node records — no error, produces garbage output
I4	format-error drops info for non-ExceptionInfo exceptions — user code eval errors show no source context
I5	REPL default resolve-keyword uses clojure.core/read-string — latent escalation point

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Fix Priority (Highest ROI)

1. H1 + H6 — TRS cross-validation: add #(inc(%)), ::foo to lang agreement tests, fix TRS #() wrapping
2. H4 — One-line fix: add metadatable? check before vary-meta in reader.cljc:431
3. M9 — One-line fix: wrap anon-fn-depth in try/finally like sq-depth
4. M1-M4, M11-M12 — Single tokenizer layer: validate symbol/keyword structure after scanning
5. M7 — Strip BOM in file reader path
6. M10 — Copy surrogate range check from parse-unicode-escape to resolve-char
7. H3 — Special-case #:: in tokenizer dispatch (don't let read-symbol-str consume :)
8. M15 — Add map? and set? cases to restore-bare-percent

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Defenses Confirmed (What We Failed to Break)

Defense	Hypotheses Refuted
Number validation (1.2.3, 0xGG, 1/0, 1.5N, 1/2/3)	5
Formatter idempotency at all widths including width=1	2
Error messages with accurate source locations	5
CLI: missing files, unknown commands, wrong extensions	5
Eval semantics for all tested programs	5
200+ level nesting without stack overflow	2
Duplicate map key detection	1
Odd-element-count map detection	1
Reader conditional validation (wrong arity, odd elements)	2
Stage contract validation	5
Regex validation for invalid patterns	1
Character literal roundtrip (named, unicode, octal)	5
Lang agreement on standard forms	4
All 918 JVM + 771 CLJS tests pass	—

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50+ hypotheses tested via REPL. 5 deep-dive code analysis agents. 40 findings confirmed across 4 severity levels. 70+ hypotheses refuted.