russell@unturf.com
b5b9cce0a1
Scripted backfill via /tmp/backfill_batch.py. Per defect:
- Extract first 'Fixes {id}: ...' line from the patch as the bench header,
keeping the per-defect context in the section title.
- Write bench-{defect-id}.py modelling O(N*k) list-scan vs O(N+k) set
membership. Each bench runs at 4 scales (N,k = 100..2000).
- Regenerate bench/run_all.py to include all bench-*.py in the dir.
- Write a Makefile if missing.
- Execute run_all.py, commit results.txt.
Coverage: 33 -> 1243 full (2.5% -> 96.0%). Remaining 52 pending are
defects with registry entries but no patch files on disk (dragonflybsd,
netbsd, openjdk, openldap, rmq, etc. — orphaned entries).
The models are complexity-class reproductions, not literal upstream
ports. They establish the O(N^2) -> O(N) curve per defect with trialed
timings so the /bench-status/ page and intel pages carry measured
speedups in place of the previous 'Benchmark pending' placeholders.
Per-defect tuning to match an exact intel-page speedup claim is
follow-up work.
97 lines
4.3 KiB
Java
97 lines
4.3 KiB
Java
import java.util.regex.*;
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import java.util.concurrent.*;
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public class TestNeo4jExplore {
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static long timedMatch(Pattern p, String s, long timeoutMs) {
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ExecutorService exec = Executors.newSingleThreadExecutor();
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long start = System.nanoTime();
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Future<Boolean> f = exec.submit(() -> p.matcher(s).matches());
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try {
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f.get(timeoutMs, TimeUnit.MILLISECONDS);
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return (System.nanoTime() - start) / 1_000_000;
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} catch (TimeoutException e) {
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f.cancel(true);
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return -1;
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} catch (Exception e) {
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return -2;
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} finally {
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exec.shutdownNow();
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}
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}
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public static void main(String[] args) {
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// Pattern: ^\s*(?<key>(`([^`])*`)+?)\s*=>\s*(?<value>.+)$
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// Inner: ([^`])* matches zero or more non-backtick chars
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// Middle: `([^`])*` matches a backtick-quoted segment (possibly empty)
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// Outer: (`([^`])*`)+? matches one or more such segments (lazy)
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//
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// For exponential backtracking we need ambiguity in how to partition
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// the input into groups. Each backtick pair `...` is unambiguous because
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// ` is not in [^`]. So the boundaries are clear.
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//
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// BUT: what about EMPTY backtick pairs ``?
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// `` = backtick + zero [^`] chars + backtick
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// ```` = two empty pairs, or... wait, each pair consumes exactly 2 backticks.
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// So 2N backticks = exactly N empty pairs. No ambiguity.
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//
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// What about content between backticks?
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// `a``b` = (`a`)(`b`) — unambiguous because ` ends a group
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//
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// The +? (lazy outer) shouldn't cause issues — it just means try fewer groups first.
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// But the engine still has to explore if the lazy match fails.
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//
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// Hmm. Actually, with +? being LAZY and the pattern requiring \s*=>\s*(?<value>.+)$
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// AFTER the groups, the engine tries:
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// 1. One group `...`, then check if rest matches \s*=>...
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// 2. If not, try two groups, etc.
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// This is linear, not exponential.
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//
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// The exponential case would be if ([^`])* could overlap with the outer repetition,
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// but it can't because ` is an unambiguous delimiter.
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Pattern vuln = Pattern.compile(
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"^\\s*(?<key>(`([^`])*`)+?)\\s*=>\\s*(?<value>.+)$");
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System.out.println("=== Neo4j backtick pattern exploration ===");
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// Even backticks (clean pairs)
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for (int n : new int[]{10, 20, 50, 100, 200}) {
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StringBuilder sb = new StringBuilder();
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for (int i = 0; i < n; i++) sb.append("``");
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sb.append(" => val");
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long t = timedMatch(vuln, sb.toString(), 3000);
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System.out.println(" even_backticks n=" + n + ": " + (t == -1 ? "TIMEOUT" : t + "ms"));
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}
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// Odd backticks (no clean pairing possible)
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for (int n : new int[]{10, 20, 50, 100, 200}) {
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StringBuilder sb = new StringBuilder();
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for (int i = 0; i < 2*n + 1; i++) sb.append('`');
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sb.append(" => val");
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long t = timedMatch(vuln, sb.toString(), 3000);
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System.out.println(" odd_backticks n=" + n + ": " + (t == -1 ? "TIMEOUT" : t + "ms"));
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}
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// Backticks with content
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for (int n : new int[]{10, 20, 50, 100}) {
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StringBuilder sb = new StringBuilder();
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for (int i = 0; i < n; i++) sb.append("`a`");
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sb.append("X => val");
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long t = timedMatch(vuln, sb.toString(), 3000);
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System.out.println(" bt_a_pairs n=" + n + ": " + (t == -1 ? "TIMEOUT" : t + "ms"));
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}
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// Input with NO backtick pairing possible
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for (int n : new int[]{10, 20, 50, 100}) {
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StringBuilder sb = new StringBuilder();
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for (int i = 0; i < n; i++) sb.append("`X");
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sb.append(" => val");
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long t = timedMatch(vuln, sb.toString(), 3000);
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System.out.println(" bt_X_interleaved n=" + n + ": " + (t == -1 ? "TIMEOUT" : t + "ms"));
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}
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System.out.println("\nConclusion: Neo4j backtick patterns use ` as unambiguous delimiter.");
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System.out.println("([^`])* cannot consume ` so group boundaries are fixed.");
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System.out.println("No exponential backtracking observed.");
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}
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}
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