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depot/third_party/nixpkgs/pkgs/development/libraries/expat/2.6.0-fix-tests-flakiness.patch
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GitOrigin-RevId: 1536926ef5621b09bba54035ae2bb6d806d72ac8
2024-02-29 21:09:43 +01:00

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diff --git a/lib/internal.h b/lib/internal.h
index cce71e4c..a217b3f9 100644
--- a/lib/internal.h
+++ b/lib/internal.h
@@ -31,7 +31,7 @@
Copyright (c) 2016-2023 Sebastian Pipping <sebastian@pipping.org>
Copyright (c) 2018 Yury Gribov <tetra2005@gmail.com>
Copyright (c) 2019 David Loffredo <loffredo@steptools.com>
- Copyright (c) 2023 Sony Corporation / Snild Dolkow <snild@sony.com>
+ Copyright (c) 2023-2024 Sony Corporation / Snild Dolkow <snild@sony.com>
Licensed under the MIT license:
Permission is hereby granted, free of charge, to any person obtaining
@@ -162,7 +162,7 @@ const char *unsignedCharToPrintable(unsigned char c);
#endif
extern XML_Bool g_reparseDeferralEnabledDefault; // written ONLY in runtests.c
-extern unsigned int g_parseAttempts; // used for testing only
+extern unsigned int g_bytesScanned; // used for testing only
#ifdef __cplusplus
}
diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index aaf0fa9c..6de99d99 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -38,7 +38,7 @@
Copyright (c) 2022 Jann Horn <jannh@google.com>
Copyright (c) 2022 Sean McBride <sean@rogue-research.com>
Copyright (c) 2023 Owain Davies <owaind@bath.edu>
- Copyright (c) 2023 Sony Corporation / Snild Dolkow <snild@sony.com>
+ Copyright (c) 2023-2024 Sony Corporation / Snild Dolkow <snild@sony.com>
Licensed under the MIT license:
Permission is hereby granted, free of charge, to any person obtaining
@@ -630,7 +630,7 @@ static unsigned long getDebugLevel(const char *variableName,
: ((*((pool)->ptr)++ = c), 1))
XML_Bool g_reparseDeferralEnabledDefault = XML_TRUE; // write ONLY in runtests.c
-unsigned int g_parseAttempts = 0; // used for testing only
+unsigned int g_bytesScanned = 0; // used for testing only
struct XML_ParserStruct {
/* The first member must be m_userData so that the XML_GetUserData
@@ -1017,7 +1017,7 @@ callProcessor(XML_Parser parser, const char *start, const char *end,
return XML_ERROR_NONE;
}
}
- g_parseAttempts += 1;
+ g_bytesScanned += (unsigned)have_now;
const enum XML_Error ret = parser->m_processor(parser, start, end, endPtr);
if (ret == XML_ERROR_NONE) {
// if we consumed nothing, remember what we had on this parse attempt.
diff --git a/tests/basic_tests.c b/tests/basic_tests.c
index 7112a440..a9cc3861 100644
--- a/tests/basic_tests.c
+++ b/tests/basic_tests.c
@@ -5202,13 +5202,7 @@ START_TEST(test_nested_entity_suspend) {
END_TEST
/* Regression test for quadratic parsing on large tokens */
-START_TEST(test_big_tokens_take_linear_time) {
- const char *const too_slow_failure_message
- = "Compared to the baseline runtime of the first test, this test has a "
- "slowdown of more than <max_slowdown>. "
- "Please keep increasing the value by 1 until it reliably passes the "
- "test on your hardware and open a bug sharing that number with us. "
- "Thanks in advance!";
+START_TEST(test_big_tokens_scale_linearly) {
const struct {
const char *pre;
const char *post;
@@ -5220,65 +5214,57 @@ START_TEST(test_big_tokens_take_linear_time) {
{"<e><", "/></e>"}, // big elem name, used to be O(N²)
};
const int num_cases = sizeof(text) / sizeof(text[0]);
- // For the test we need a <max_slowdown> value that is:
- // (1) big enough that the test passes reliably (avoiding flaky tests), and
- // (2) small enough that the test actually catches regressions.
- const int max_slowdown = 15;
char aaaaaa[4096];
const int fillsize = (int)sizeof(aaaaaa);
const int fillcount = 100;
+ const unsigned approx_bytes = fillsize * fillcount; // ignore pre/post.
+ const unsigned max_factor = 4;
+ const unsigned max_scanned = max_factor * approx_bytes;
memset(aaaaaa, 'a', fillsize);
if (! g_reparseDeferralEnabledDefault) {
return; // heuristic is disabled; we would get O(n^2) and fail.
}
-#if ! defined(__linux__)
- if (CLOCKS_PER_SEC < 100000) {
- // Skip this test if clock() doesn't have reasonably good resolution.
- // This workaround is primarily targeting Windows and FreeBSD, since
- // XSI requires the value to be 1.000.000 (10x the condition here), and
- // we want to be very sure that at least one platform in CI can catch
- // regressions (through a failing test).
- return;
- }
-#endif
- clock_t baseline = 0;
for (int i = 0; i < num_cases; ++i) {
XML_Parser parser = XML_ParserCreate(NULL);
assert_true(parser != NULL);
enum XML_Status status;
- set_subtest("max_slowdown=%d text=\"%saaaaaa%s\"", max_slowdown,
- text[i].pre, text[i].post);
- const clock_t start = clock();
+ set_subtest("text=\"%saaaaaa%s\"", text[i].pre, text[i].post);
// parse the start text
+ g_bytesScanned = 0;
status = _XML_Parse_SINGLE_BYTES(parser, text[i].pre,
(int)strlen(text[i].pre), XML_FALSE);
if (status != XML_STATUS_OK) {
xml_failure(parser);
}
+
// parse lots of 'a', failing the test early if it takes too long
+ unsigned past_max_count = 0;
for (int f = 0; f < fillcount; ++f) {
status = _XML_Parse_SINGLE_BYTES(parser, aaaaaa, fillsize, XML_FALSE);
if (status != XML_STATUS_OK) {
xml_failure(parser);
}
- // i == 0 means we're still calculating the baseline value
- if (i > 0) {
- const clock_t now = clock();
- const clock_t clocks_so_far = now - start;
- const int slowdown = clocks_so_far / baseline;
- if (slowdown >= max_slowdown) {
- fprintf(
- stderr,
- "fill#%d: clocks_so_far=%d baseline=%d slowdown=%d max_slowdown=%d\n",
- f, (int)clocks_so_far, (int)baseline, slowdown, max_slowdown);
- fail(too_slow_failure_message);
- }
+ if (g_bytesScanned > max_scanned) {
+ // We're not done, and have already passed the limit -- the test will
+ // definitely fail. This block allows us to save time by failing early.
+ const unsigned pushed
+ = (unsigned)strlen(text[i].pre) + (f + 1) * fillsize;
+ fprintf(
+ stderr,
+ "after %d/%d loops: pushed=%u scanned=%u (factor ~%.2f) max_scanned: %u (factor ~%u)\n",
+ f + 1, fillcount, pushed, g_bytesScanned,
+ g_bytesScanned / (double)pushed, max_scanned, max_factor);
+ past_max_count++;
+ // We are failing, but allow a few log prints first. If we don't reach
+ // a count of five, the test will fail after the loop instead.
+ assert_true(past_max_count < 5);
}
}
+
// parse the end text
status = _XML_Parse_SINGLE_BYTES(parser, text[i].post,
(int)strlen(text[i].post), XML_TRUE);
@@ -5286,18 +5272,14 @@ START_TEST(test_big_tokens_take_linear_time) {
xml_failure(parser);
}
- // how long did it take in total?
- const clock_t end = clock();
- const clock_t taken = end - start;
- if (i == 0) {
- assert_true(taken > 0); // just to make sure we don't div-by-0 later
- baseline = taken;
- }
- const int slowdown = taken / baseline;
- if (slowdown >= max_slowdown) {
- fprintf(stderr, "taken=%d baseline=%d slowdown=%d max_slowdown=%d\n",
- (int)taken, (int)baseline, slowdown, max_slowdown);
- fail(too_slow_failure_message);
+ assert_true(g_bytesScanned > approx_bytes); // or the counter isn't working
+ if (g_bytesScanned > max_scanned) {
+ fprintf(
+ stderr,
+ "after all input: scanned=%u (factor ~%.2f) max_scanned: %u (factor ~%u)\n",
+ g_bytesScanned, g_bytesScanned / (double)approx_bytes, max_scanned,
+ max_factor);
+ fail("scanned too many bytes");
}
XML_ParserFree(parser);
@@ -5774,19 +5756,17 @@ START_TEST(test_varying_buffer_fills) {
fillsize[2], fillsize[3]);
XML_Parser parser = XML_ParserCreate(NULL);
assert_true(parser != NULL);
- g_parseAttempts = 0;
CharData storage;
CharData_Init(&storage);
XML_SetUserData(parser, &storage);
XML_SetStartElementHandler(parser, start_element_event_handler);
+ g_bytesScanned = 0;
int worstcase_bytes = 0; // sum of (buffered bytes at each XML_Parse call)
- int scanned_bytes = 0; // sum of (buffered bytes at each actual parse)
int offset = 0;
while (*fillsize >= 0) {
assert_true(offset + *fillsize <= document_length); // or test is invalid
- const unsigned attempts_before = g_parseAttempts;
const enum XML_Status status
= XML_Parse(parser, &document[offset], *fillsize, XML_FALSE);
if (status != XML_STATUS_OK) {
@@ -5796,28 +5776,20 @@ START_TEST(test_varying_buffer_fills) {
fillsize++;
assert_true(offset <= INT_MAX - worstcase_bytes); // avoid overflow
worstcase_bytes += offset; // we might've tried to parse all pending bytes
- if (g_parseAttempts != attempts_before) {
- assert_true(g_parseAttempts == attempts_before + 1); // max 1/XML_Parse
- assert_true(offset <= INT_MAX - scanned_bytes); // avoid overflow
- scanned_bytes += offset; // we *did* try to parse all pending bytes
- }
}
assert_true(storage.count == 1); // the big token should've been parsed
- assert_true(scanned_bytes > 0); // test-the-test: does our counter work?
+ assert_true(g_bytesScanned > 0); // test-the-test: does our counter work?
if (g_reparseDeferralEnabledDefault) {
// heuristic is enabled; some XML_Parse calls may have deferred reparsing
- const int max_bytes_scanned = -*fillsize;
- if (scanned_bytes > max_bytes_scanned) {
+ const unsigned max_bytes_scanned = -*fillsize;
+ if (g_bytesScanned > max_bytes_scanned) {
fprintf(stderr,
- "bytes scanned in parse attempts: actual=%d limit=%d \n",
- scanned_bytes, max_bytes_scanned);
+ "bytes scanned in parse attempts: actual=%u limit=%u \n",
+ g_bytesScanned, max_bytes_scanned);
fail("too many bytes scanned in parse attempts");
}
- assert_true(scanned_bytes <= worstcase_bytes);
- } else {
- // heuristic is disabled; every XML_Parse() will have reparsed
- assert_true(scanned_bytes == worstcase_bytes);
}
+ assert_true(g_bytesScanned <= (unsigned)worstcase_bytes);
XML_ParserFree(parser);
}
@@ -6065,7 +6037,7 @@ make_basic_test_case(Suite *s) {
tcase_add_test__ifdef_xml_dtd(tc_basic,
test_pool_integrity_with_unfinished_attr);
tcase_add_test__if_xml_ge(tc_basic, test_nested_entity_suspend);
- tcase_add_test(tc_basic, test_big_tokens_take_linear_time);
+ tcase_add_test(tc_basic, test_big_tokens_scale_linearly);
tcase_add_test(tc_basic, test_set_reparse_deferral);
tcase_add_test(tc_basic, test_reparse_deferral_is_inherited);
tcase_add_test(tc_basic, test_set_reparse_deferral_on_null_parser);
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