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fuzztest-rust | add continue_after_crash support to fuzzing and replay-corpus modes #2191

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Merged
copybara-service merged 1 commit into from
Aug 19, 2026
Merged

fuzztest-rust | add continue_after_crash support to fuzzing and replay-corpus modes #2191

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95 changes: 94 additions & 1 deletion rust/cargo_fuzztest/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -100,6 +100,7 @@ impl CargoFuzzTestOptions {
.fuzz_for
.unwrap_or(RunDuration::Indefinitely),
jobs: self.fuzztest_options.jobs,
continue_after_crash: self.fuzztest_options.continue_after_crash,
})
} else {
mode
Expand Down Expand Up @@ -248,11 +249,14 @@ impl FuzztestRunner {
}

ExecutionMode::Fuzz(fuzz_options) => {
let FuzzOptions { fuzz_for, jobs } = fuzz_options;
let FuzzOptions { fuzz_for, jobs, continue_after_crash } = fuzz_options;
cmd.env("FUZZTEST_FUZZ_FOR", fuzz_for.to_string());
if let Some(jobs) = jobs {
cmd.env("FUZZTEST_JOBS", jobs.to_string());
}
if continue_after_crash {
cmd.env("FUZZTEST_CONTINUE_AFTER_CRASH", "true");
}
}

ExecutionMode::ReplayCrash(replay_options) => {
Expand All @@ -273,6 +277,9 @@ impl FuzztestRunner {
TimeBudgetType::Total => "total",
};
cmd.env("FUZZTEST_TIME_BUDGET_TYPE", time_budget_str);
if replay_corpus_options.continue_after_crash {
cmd.env("FUZZTEST_CONTINUE_AFTER_CRASH", "true");
}
}

ExecutionMode::ListCrashIds(list_crash_ids_options) => {
Expand Down Expand Up @@ -609,6 +616,7 @@ mod tests {
replay_corpus_for: "10s".parse().expect("valid duration string"),
time_budget_type: TimeBudgetType::PerTest,
jobs: None,
continue_after_crash: false,
})
);
}
Expand Down Expand Up @@ -637,6 +645,7 @@ mod tests {
replay_corpus_for: RunDuration::Indefinitely,
time_budget_type: TimeBudgetType::PerTest,
jobs: None,
continue_after_crash: false,
})
);
}
Expand All @@ -662,6 +671,7 @@ mod tests {
replay_corpus_for: RunDuration::Indefinitely,
time_budget_type: TimeBudgetType::PerTest,
jobs: None,
continue_after_crash: false,
})
);
}
Expand Down Expand Up @@ -691,6 +701,7 @@ mod tests {
replay_corpus_for: "10s".parse().unwrap(),
time_budget_type: TimeBudgetType::Total,
jobs: None,
continue_after_crash: false,
})
);
}
Expand Down Expand Up @@ -879,4 +890,86 @@ mod tests {
Some("/custom/centipede".to_string())
)));
}

#[gtest]
fn test_cli_option_parsing_continue_after_crash_flag() {
let parsed = CargoFuzzTestOptions::try_parse_from([
"cargo-fuzztest",
"--fuzz-for",
"5s",
"--continue-after-crash",
"--centipede-binary-path",
"/custom/centipede",
])
.unwrap();

assert!(parsed.fuzztest_options.continue_after_crash);
let mode = parsed.execution_mode().unwrap();
let expected_duration = "5s".parse().unwrap();
assert_eq!(
mode,
ExecutionMode::Fuzz(FuzzOptions {
fuzz_for: RunDuration::Fixed(expected_duration),
jobs: None,
continue_after_crash: true,
})
);
}

#[gtest]
fn test_build_run_command_fuzz_with_continue_after_crash() {
let options = CargoFuzzTestOptions {
fuzztest_options: FuzzTestOptions {
fuzz_for: Some("5s".parse().unwrap()),
continue_after_crash: true,
..Default::default()
},
centipede_binary_path: Some("/custom/centipede".to_string()),
..Default::default()
};
let runner = FuzztestRunner::new("x86_64-unknown-linux-gnu".to_string(), options);
let cmd =
runner.build_run_command(Path::new("/tmp/test_bin")).expect("should build run command");

let envs: Vec<(String, Option<String>)> = cmd
.get_envs()
.map(|(k, v)| {
(k.to_string_lossy().to_string(), v.map(|s| s.to_string_lossy().to_string()))
})
.collect();

assert!(
envs.contains(&("FUZZTEST_CONTINUE_AFTER_CRASH".to_string(), Some("true".to_string())))
);
assert!(envs.contains(&("FUZZTEST_FUZZ_FOR".to_string(), Some("5s".to_string()))));
}

#[gtest]
fn test_build_run_command_replay_corpus_with_continue_after_crash() {
let options = CargoFuzzTestOptions {
fuzztest_options: FuzzTestOptions {
replay_corpus_for: Some("10s".parse().expect("valid duration")),
corpus_db: Some("/tmp/corpus_db".into()),
continue_after_crash: true,
..Default::default()
},
centipede_binary_path: Some("/custom/centipede".to_string()),
..Default::default()
};
let runner = FuzztestRunner::new("x86_64-unknown-linux-gnu".to_string(), options);
let cmd =
runner.build_run_command(Path::new("/tmp/test_bin")).expect("should build run command");

let envs: Vec<(String, Option<String>)> = cmd
.get_envs()
.map(|(k, v)| {
(k.to_string_lossy().to_string(), v.map(|s| s.to_string_lossy().to_string()))
})
.collect();

assert!(
envs.contains(&("FUZZTEST_CONTINUE_AFTER_CRASH".to_string(), Some("true".to_string())))
);
assert!(envs.contains(&("FUZZTEST_REPLAY_CORPUS_FOR".to_string(), Some("10s".to_string()))));
}
}
29 changes: 29 additions & 0 deletions rust/cargo_fuzztest/tests/e2e_cli_test.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -165,6 +165,7 @@ fn test_cargo_fuzztest_e2e_replay_by_id() {
let mut cmd = setup_cargo_fuzztest_command(&sample_crate_path, temp_target_dir.path());
cmd.arg(test_target)
.arg("--fuzz-for=5s")
.arg("--continue-after-crash")
.env_remove("FUZZTEST_CENTIPEDE_BINARY_PATH")
.arg("--centipede-binary-path")
.arg(&centipede_bin)
Expand Down Expand Up @@ -248,6 +249,7 @@ fn test_cargo_fuzztest_e2e_replay_all_crashes() {
let mut cmd = setup_cargo_fuzztest_command(&sample_crate_path, temp_target_dir.path());
cmd.arg(test_target)
.arg("--fuzz-for=5s")
.arg("--continue-after-crash")
.env_remove("FUZZTEST_CENTIPEDE_BINARY_PATH")
.arg("--centipede-binary-path")
.arg(&centipede_bin)
Expand Down Expand Up @@ -412,6 +414,7 @@ fn test_cargo_fuzztest_e2e_list_crash_ids() {
let mut cmd = setup_cargo_fuzztest_command(&sample_crate_path, temp_target_dir.path());
cmd.arg(test_target)
.arg("--fuzz-for=5s")
.arg("--continue-after-crash")
.env_remove("FUZZTEST_CENTIPEDE_BINARY_PATH")
.arg("--centipede-binary-path")
.arg(&centipede_bin)
Expand Down Expand Up @@ -448,3 +451,29 @@ fn test_cargo_fuzztest_e2e_list_crash_ids() {
// good check here?
expect_true!(!crash_ids.is_empty());
}

#[gtest]
fn test_cargo_fuzztest_e2e_continue_after_crash() {
let sample_crate_path = get_sample_crate_path("another_sample_fuzz_crate");
let test_target = "__fuzztest_mod__crashing_fuzztest_target::crashing_fuzztest_target";

let temp_target_dir = TempDir::new().expect("Failed to create temporary target directory");
let centipede_bin = env::var("FUZZTEST_CENTIPEDE_BINARY_PATH")
.expect("FUZZTEST_CENTIPEDE_BINARY_PATH needs to be set for the test");

let mut cmd = setup_cargo_fuzztest_command(&sample_crate_path, temp_target_dir.path());
cmd.arg(test_target)
.arg("--fuzz-for=3s")
.arg("--continue-after-crash")
.env_remove("FUZZTEST_CENTIPEDE_BINARY_PATH")
.arg("--centipede-binary-path")
.arg(&centipede_bin)
.env("FUZZTEST_PRINT_SUBPROCESS_LOG", "true");

let output = cmd.output().expect("Failed to run cargo-fuzztest with continue-after-crash");
let stderr_str = String::from_utf8_lossy(&output.stderr);

expect_true!(output.status.success());
expect_true!(stderr_str.contains("Property function ran but crashed."));
expect_true!(stderr_str.contains("Crashing bug found!"));
}
22 changes: 11 additions & 11 deletions rust/cargo_fuzztest/tests/runner_test.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,7 @@ fn test_runner_build_run_command_with_target() {
centipede_binary_path: Some("/custom/path/to/centipede".to_string()),
..Default::default()
};
let runner = FuzztestRunner::new("x86_64-unknown-linux-gnu".to_string(), options);
let runner = FuzztestRunner::new("sample-host-triple".to_string(), options);
let cmd = runner.build_run_command(&binary_path).expect("valid run command");

let args: Vec<String> = cmd.get_args().map(|s| s.to_string_lossy().to_string()).collect();
Expand All @@ -52,7 +52,7 @@ fn test_runner_build_run_command_with_duration() {
centipede_binary_path: Some("/custom/path/to/centipede".to_string()),
..Default::default()
};
let runner = FuzztestRunner::new("x86_64-unknown-linux-gnu".to_string(), options);
let runner = FuzztestRunner::new("sample-host-triple".to_string(), options);
let cmd = runner.build_run_command(&binary_path).expect("valid run command");

let envs: Vec<(String, Option<String>)> = cmd
Expand All @@ -72,7 +72,7 @@ fn test_runner_build_run_command_with_indefinitely() {
centipede_binary_path: Some("/custom/path/to/centipede".to_string()),
..Default::default()
};
let runner = FuzztestRunner::new("x86_64-unknown-linux-gnu".to_string(), options);
let runner = FuzztestRunner::new("sample-host-triple".to_string(), options);
let cmd = runner.build_run_command(&binary_path).expect("valid run command");

let envs: Vec<(String, Option<String>)> = cmd
Expand All @@ -89,7 +89,7 @@ fn test_runner_build_run_command_with_centipede_binary_path() {
centipede_binary_path: Some("/custom/path/to/centipede".to_string()),
..Default::default()
};
let runner = FuzztestRunner::new("x86_64-unknown-linux-gnu".to_string(), options);
let runner = FuzztestRunner::new("sample-host-triple".to_string(), options);
let cmd = runner.build_run_command(&binary_path).expect("valid run command");

let envs: Vec<(String, Option<String>)> = cmd
Expand All @@ -115,7 +115,7 @@ fn test_runner_build_run_command_with_jobs() {
centipede_binary_path: Some("/custom/path/to/centipede".to_string()),
..Default::default()
};
let runner = FuzztestRunner::new("x86_64-unknown-linux-gnu".to_string(), options);
let runner = FuzztestRunner::new("sample-host-triple".to_string(), options);
let cmd = runner.build_run_command(&binary_path).expect("valid run command");

let envs: Vec<(String, Option<String>)> = cmd
Expand All @@ -131,7 +131,7 @@ fn test_runner_build_run_command_with_jobs_only() {
let binary_path = get_sample_test_bin_path("sample_fuzz_crate");
let fuzztest_options = FuzzTestOptions { jobs: Some(4), ..Default::default() };
let options = CargoFuzzTestOptions { fuzztest_options, ..Default::default() };
let runner = FuzztestRunner::new("x86_64-unknown-linux-gnu".to_string(), options);
let runner = FuzztestRunner::new("sample-host-triple".to_string(), options);
let cmd = runner.build_run_command(&binary_path).expect("valid run command");

let envs: Vec<(String, Option<String>)> = cmd
Expand All @@ -155,7 +155,7 @@ fn test_runner_build_run_command_with_replay_id() {
centipede_binary_path: Some("/custom/path/to/centipede".to_string()),
..Default::default()
};
let runner = FuzztestRunner::new("x86_64-unknown-linux-gnu".to_string(), options);
let runner = FuzztestRunner::new("sample-host-triple".to_string(), options);
let cmd = runner.build_run_command(&binary_path).expect("valid run command");

let envs: Vec<(String, Option<String>)> = cmd
Expand Down Expand Up @@ -217,7 +217,7 @@ fn test_runner_build_run_command_with_replay_findings() {
centipede_binary_path: Some("/custom/path/to/centipede".to_string()),
..Default::default()
};
let runner = FuzztestRunner::new("x86_64-unknown-linux-gnu".to_string(), options);
let runner = FuzztestRunner::new("sample-host-triple".to_string(), options);
let cmd = runner.build_run_command(&binary_path).expect("valid run command");

let envs: Vec<(String, Option<String>)> = cmd
Expand Down Expand Up @@ -263,7 +263,7 @@ fn test_runner_build_run_command_with_replay_corpus() {
centipede_binary_path: Some("/custom/path/to/centipede".to_string()),
..Default::default()
};
let runner = FuzztestRunner::new("x86_64-unknown-linux-gnu".to_string(), options);
let runner = FuzztestRunner::new("sample-host-triple".to_string(), options);
let cmd = runner.build_run_command(&binary_path).expect("valid run command");

let envs: Vec<(String, Option<String>)> = cmd
Expand Down Expand Up @@ -300,7 +300,7 @@ fn test_runner_build_run_command_with_replay_corpus_indefinitely() {
centipede_binary_path: Some("/custom/path/to/centipede".to_string()),
..Default::default()
};
let runner = FuzztestRunner::new("x86_64-unknown-linux-gnu".to_string(), options);
let runner = FuzztestRunner::new("sample-host-triple".to_string(), options);
let cmd = runner.build_run_command(&binary_path).expect("valid run command");

let envs: Vec<(String, Option<String>)> = cmd
Expand Down Expand Up @@ -367,7 +367,7 @@ fn test_runner_build_run_command_with_list_crash_ids() {
centipede_binary_path: Some("/custom/path/to/centipede".to_string()),
..Default::default()
};
let runner = FuzztestRunner::new("x86_64-unknown-linux-gnu".to_string(), options);
let runner = FuzztestRunner::new("sample-host-triple".to_string(), options);
let cmd = runner.build_run_command(&binary_path).expect("valid run command");

let envs: Vec<(String, Option<String>)> = cmd
Expand Down
2 changes: 2 additions & 0 deletions rust/e2e_tests/replay_test.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,7 @@ fn replay_by_id_reproduces_panic(fixture: &EnvVars) {
.arg(test_name)
.arg("--exact")
.env("FUZZTEST_FUZZ_FOR", "15s")
.env("FUZZTEST_CONTINUE_AFTER_CRASH", "true")
.env("FUZZTEST_CORPUS_DB", &db_dir)
.env("FUZZTEST_WORKDIR_ROOT", &workdir_root_dir)
.env("FUZZTEST_CENTIPEDE_BINARY_PATH", &fixture.centipede_path)
Expand Down Expand Up @@ -127,6 +128,7 @@ fn replay_all_reproduces_all_failures(fixture: &EnvVars) {
.arg(test_name)
.arg("--exact")
.env("FUZZTEST_FUZZ_FOR", "15s")
.env("FUZZTEST_CONTINUE_AFTER_CRASH", "true")
.env("FUZZTEST_CORPUS_DB", &db_dir)
.env("FUZZTEST_WORKDIR_ROOT", &workdir_root_dir)
.env("FUZZTEST_CENTIPEDE_BINARY_PATH", &fixture.centipede_path)
Expand Down
27 changes: 27 additions & 0 deletions rust/e2e_tests/standalone_mode_test.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -95,12 +95,39 @@ fn standalone_mode_handles_worker_crash(fixture: &EnvVars) {
let output = process.wait_with_output().expect("Should terminate");
let stderr = String::from_utf8_lossy(&output.stderr);

// By default continue_after_crash is false, so finding a crash causes test failure.
expect_false!(output.status.success());
expect_that!(stderr, matchers::contains_substring("Property function ran but crashed."));
expect_that!(stderr, matchers::contains_regex("Signature[ \t]*: Unwinding panic"));
// Centipede prefixes logs from the crashing worker with "CRASH LOG: ".
expect_that!(stderr, matchers::contains_substring("CRASH LOG: Bug found!"));
}

#[gtest]
fn standalone_mode_continues_after_crash_when_enabled(fixture: &EnvVars) {
let test_name = "__fuzztest_mod__find_bug_fuzz_test::find_bug_fuzz_test";

let process = Command::new(&fixture.target_binary_path)
.arg(test_name)
.env("FUZZTEST_FUZZ_FOR", "15s")
.env("FUZZTEST_CONTINUE_AFTER_CRASH", "true")
.env("FUZZTEST_PRINT_SUBPROCESS_LOG", "true")
.env("FUZZTEST_CENTIPEDE_BINARY_PATH", &fixture.centipede_path)
.env("RUST_TEST_NOCAPTURE", "1")
.stdout(std::process::Stdio::piped())
.stderr(std::process::Stdio::piped())
.spawn()
.expect("Failed to spawn binary");

let output = process.wait_with_output().expect("Should terminate");
let stderr = String::from_utf8_lossy(&output.stderr);

// With continue_after_crash=true, the fuzz test runs for the full time limit and exits cleanly.
expect_true!(output.status.success());
expect_that!(stderr, matchers::contains_substring("Property function ran but crashed."));
expect_that!(stderr, matchers::contains_substring("CRASH LOG: Bug found!"));
}

#[gtest]
fn standalone_mode_spawns_parallel_jobs(fixture: &EnvVars) {
let target_binary_path =
Expand Down
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