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Copy pathwal.rs
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743 lines (639 loc) · 28.2 KB
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//! Write-Ahead Log (WAL) for Minigraf.
//!
//! The WAL sidecar file (`<db>.wal`) stores committed transaction entries as
//! CRC32-protected binary records. Facts go to the WAL before the main file,
//! ensuring crash safety.
//!
//! # File layout
//!
//! ```text
//! WAL header (32 bytes):
//! magic: [u8; 4] = b"MWAL"
//! version: u32 LE = 1
//! reserved: [u8; 24]
//!
//! WAL entries (variable length, sequential):
//! checksum: u32 LE CRC32 of everything after this field in this entry
//! tx_count: u64 LE monotonic counter from FactStorage
//! num_facts: u64 LE
//! facts: for each fact: fact_len: u32 LE | fact_bytes: [u8; fact_len]
//! ```
use crate::db::SyncMode;
use crate::error::{ErrorCode, bail_coded, err_coded};
use crate::graph::types::Fact;
use crate::storage::packed_pages::MAX_FACT_BYTES;
use anyhow::Result;
use std::fs::{File, OpenOptions};
use std::io::{self, Read, Seek, SeekFrom, Write};
use std::path::Path;
const WAL_MAGIC: [u8; 4] = *b"MWAL";
const WAL_VERSION: u32 = 1;
const WAL_HEADER_SIZE: usize = 32;
// ─── WAL Header ─────────────────────────────────────────────────────────────
fn write_wal_header(file: &mut File) -> Result<()> {
let mut buf = [0u8; WAL_HEADER_SIZE];
buf[0..4].copy_from_slice(&WAL_MAGIC);
buf[4..8].copy_from_slice(&WAL_VERSION.to_le_bytes());
// bytes 8..32 are reserved zeros
file.seek(SeekFrom::Start(0))?;
file.write_all(&buf)?;
file.sync_all()?;
Ok(())
}
fn validate_wal_header(file: &mut File) -> Result<()> {
let mut buf = [0u8; WAL_HEADER_SIZE];
file.seek(SeekFrom::Start(0))?;
file.read_exact(&mut buf)?;
if buf[0..4] != WAL_MAGIC {
bail_coded!(ErrorCode::Wal001);
}
let version = u32::from_le_bytes([buf[4], buf[5], buf[6], buf[7]]);
if version != WAL_VERSION {
bail_coded!(ErrorCode::Wal002, version, WAL_VERSION);
}
Ok(())
}
/// Whether an existing WAL file's header is intact, or too short to
/// contain one at all.
enum WalHeaderState {
/// At least `WAL_HEADER_SIZE` bytes present; validated by
/// `validate_wal_header` (magic/version checked separately).
Present,
/// Fewer than `WAL_HEADER_SIZE` bytes on disk. This can only happen
/// from a crash between `create_new` and `write_wal_header` completing
/// in `WalWriter::open_or_create` -- before any `WalWriter` existed to
/// append an entry with. Safe to treat as an empty WAL (#308-class
/// fix: the same "kill mid multi-step file write" window that
/// corrupted the main `.graph` header applies here to the WAL sidecar).
Absent,
}
/// Distinguishes a too-short WAL file from one long enough to validate.
/// Does not itself validate magic/version -- callers still run
/// `validate_wal_header` on the `Present` case.
fn check_wal_header_length(file: &mut File) -> Result<WalHeaderState> {
let len = file.metadata()?.len();
if len < WAL_HEADER_SIZE as u64 {
Ok(WalHeaderState::Absent)
} else {
Ok(WalHeaderState::Present)
}
}
// ─── Entry serialization ────────────────────────────────────────────────────
fn serialize_entry(tx_count: u64, facts: &[Fact]) -> Result<Vec<u8>> {
// Build payload (everything covered by the checksum)
let mut payload: Vec<u8> = Vec::new();
payload.extend_from_slice(&tx_count.to_le_bytes());
payload.extend_from_slice(&(facts.len() as u64).to_le_bytes());
for fact in facts {
let fact_bytes = postcard::to_allocvec(fact)?;
if fact_bytes.len() > MAX_FACT_BYTES {
bail_coded!(ErrorCode::Wal003, fact_bytes.len(), MAX_FACT_BYTES);
}
let fact_len = u32::try_from(fact_bytes.len())
.map_err(|_| err_coded!(ErrorCode::Wal004, fact_bytes.len()))?;
payload.extend_from_slice(&fact_len.to_le_bytes());
payload.extend_from_slice(&fact_bytes);
}
let checksum = crc32fast::hash(&payload);
let mut entry = Vec::with_capacity(payload.len().saturating_add(4));
entry.extend_from_slice(&checksum.to_le_bytes());
entry.extend_from_slice(&payload);
Ok(entry)
}
// ─── Public types ───────────────────────────────────────────────────────────
/// A single committed transaction entry read from the WAL.
#[derive(Debug)]
pub struct WalEntry {
pub tx_count: u64,
pub facts: Vec<Fact>,
}
// ─── WalWriter ──────────────────────────────────────────────────────────────
/// Appends committed transaction entries to the WAL sidecar file.
///
/// Created by `Minigraf::open()` for file-backed databases.
/// Not used for in-memory databases.
pub struct WalWriter {
file: File,
sync_mode: SyncMode,
}
impl WalWriter {
/// Open an existing WAL or create a new one.
///
/// If creating, writes the WAL header.
/// If opening, validates the header and seeks to the end for appending.
pub fn open_or_create(path: &Path, sync_mode: SyncMode) -> Result<Self> {
// Try atomic create-new first (no TOCTOU window)
match OpenOptions::new()
.read(true)
.write(true)
.create_new(true)
.open(path)
{
Ok(mut file) => {
write_wal_header(&mut file)?;
file.seek(SeekFrom::End(0))?;
return Ok(WalWriter { file, sync_mode });
}
Err(e) if e.kind() == std::io::ErrorKind::AlreadyExists => {}
Err(e) => return Err(e.into()),
}
// File exists — validate its header and seek to end for appending
let mut file = OpenOptions::new().read(true).write(true).open(path)?;
match check_wal_header_length(&mut file)? {
WalHeaderState::Present => validate_wal_header(&mut file)?,
// A previous crash landed between this file's creation and its
// header write completing; no entry could have been appended
// yet, so re-initialize it as a fresh, empty WAL.
WalHeaderState::Absent => write_wal_header(&mut file)?,
}
file.seek(SeekFrom::End(0))?;
Ok(WalWriter { file, sync_mode })
}
/// The `SyncMode` this writer was opened with. Used only in tests, to
/// verify that `SyncMode` reaches `WalWriter` from every call site.
#[cfg(test)]
pub(crate) fn sync_mode(&self) -> SyncMode {
self.sync_mode
}
/// Serialize `facts` as a WAL entry and append it to the file.
///
/// The entry is written atomically from the caller's perspective:
/// a partial write produces a bad CRC32, which the reader discards.
/// Then flushes to disk, unless `sync_mode` is `SyncMode::Normal` — see [`SyncMode`].
pub fn append_entry(&mut self, tx_count: u64, facts: &[Fact]) -> Result<()> {
let entry_bytes = serialize_entry(tx_count, facts)?;
self.file.write_all(&entry_bytes)?;
match self.sync_mode {
SyncMode::Full => self.file.sync_data()?,
SyncMode::Normal => {}
}
Ok(())
}
/// Delete the WAL file at `path`. Called after a successful checkpoint.
///
/// Uses a short retry loop to tolerate Windows races where the OS file handle
/// is not immediately released after the `WalWriter` is dropped.
pub fn delete_file(path: &Path) -> Result<()> {
// Retry up to ~500 ms on Windows where handle release can lag drop().
let retries: u32 = if cfg!(windows) { 10 } else { 1 };
let mut last_err = None;
for i in 0..retries {
match std::fs::remove_file(path) {
Ok(()) => return Ok(()),
Err(e) => {
last_err = Some(e);
if i.saturating_add(1) < retries {
std::thread::sleep(std::time::Duration::from_millis(50));
}
}
}
}
Err(err_coded!(
ErrorCode::Wal006,
path.display(),
last_err
.map(|e| e.to_string())
.unwrap_or_else(|| "unknown error".to_string())
))
}
}
// ─── WalReader ──────────────────────────────────────────────────────────────
/// Reads and validates WAL entries for crash recovery.
pub struct WalReader {
file: File,
}
impl WalReader {
/// Open the WAL at `path` for reading.
pub fn open(path: &Path) -> Result<Self> {
let mut file = File::open(path)?;
match check_wal_header_length(&mut file)? {
WalHeaderState::Present => validate_wal_header(&mut file)?,
// Too short to contain a header, which can only mean a crash
// landed before any entry was ever appended (see
// `WalHeaderState::Absent`). `read_entries` already treats
// hitting EOF while reading an entry as "no more entries", so
// leaving the file as-is and letting that seek-past-end happen
// naturally is correct -- there is nothing here to replay.
WalHeaderState::Absent => {}
}
Ok(WalReader { file })
}
/// Read all valid entries from the WAL.
///
/// Reads sequentially from after the header. Stops at the first entry
/// with an invalid CRC32 (partial write) or at EOF. Earlier entries are
/// unaffected by a bad entry.
pub fn read_entries(&mut self) -> Result<Vec<WalEntry>> {
self.file.seek(SeekFrom::Start(WAL_HEADER_SIZE as u64))?;
let mut entries = Vec::new();
loop {
// Read checksum (4 bytes); EOF here means no more entries
let mut csum_buf = [0u8; 4];
match self.file.read_exact(&mut csum_buf) {
Err(e) if e.kind() == io::ErrorKind::UnexpectedEof => break,
Err(e) => return Err(e.into()),
Ok(()) => {}
}
let expected_csum = u32::from_le_bytes(csum_buf);
// Read tx_count (8 bytes)
let mut tx_count_buf = [0u8; 8];
if self.file.read_exact(&mut tx_count_buf).is_err() {
break; // truncated
}
let tx_count = u64::from_le_bytes(tx_count_buf);
// Read num_facts (8 bytes)
let mut num_facts_buf = [0u8; 8];
if self.file.read_exact(&mut num_facts_buf).is_err() {
break; // truncated
}
let num_facts = usize::try_from(u64::from_le_bytes(num_facts_buf))
.map_err(|_| err_coded!(ErrorCode::Wal005))?;
// Sanity cap: no legitimate entry has more than 1M facts
const MAX_FACTS_PER_ENTRY: usize = 1_000_000;
if num_facts > MAX_FACTS_PER_ENTRY {
break; // treat as corrupt entry
}
// Maximum fact size to prevent memory exhaustion from large facts
const MAX_FACT_SIZE: usize = 10 * 1024 * 1024; // 10MB
// Build payload for CRC32 verification
let mut payload = Vec::new();
payload.extend_from_slice(&tx_count_buf);
payload.extend_from_slice(&num_facts_buf);
// Read each fact
let mut facts = Vec::new(); // grow dynamically instead of pre-allocating
let mut truncated = false;
for _ in 0..num_facts {
let mut len_buf = [0u8; 4];
if self.file.read_exact(&mut len_buf).is_err() {
truncated = true;
break;
}
let fact_len = u32::from_le_bytes(len_buf) as usize;
if fact_len > MAX_FACT_SIZE {
truncated = true;
break;
}
payload.extend_from_slice(&len_buf);
let mut fact_bytes = vec![0u8; fact_len];
if self.file.read_exact(&mut fact_bytes).is_err() {
truncated = true;
break;
}
payload.extend_from_slice(&fact_bytes);
match postcard::from_bytes::<Fact>(&fact_bytes) {
Ok(f) => facts.push(f),
Err(_) => {
truncated = true;
break;
}
}
}
if truncated {
break;
}
// Verify CRC32 over the full payload
let actual_csum = crc32fast::hash(&payload);
if expected_csum != actual_csum {
break; // corrupted entry — stop here
}
entries.push(WalEntry { tx_count, facts });
}
Ok(entries)
}
}
// ─── Unit tests ─────────────────────────────────────────────────────────────
#[cfg(all(test, not(target_arch = "wasm32")))]
mod tests {
use super::*;
use crate::graph::types::{VALID_TIME_FOREVER, Value};
use uuid::Uuid;
fn make_fact(entity: Uuid, attr: &str, value: Value, tx_count: u64) -> Fact {
Fact::with_valid_time(
entity,
attr.to_string(),
value,
1000,
tx_count,
0,
VALID_TIME_FOREVER,
)
}
#[test]
fn test_wal_empty_round_trip() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("test.wal");
let _writer = WalWriter::open_or_create(&path, SyncMode::Full).unwrap();
let mut reader = WalReader::open(&path).unwrap();
let entries = reader.read_entries().unwrap();
assert!(entries.is_empty(), "new WAL should have no entries");
}
#[test]
fn test_wal_single_fact_round_trip() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("test.wal");
let alice = Uuid::new_v4();
let fact = make_fact(alice, ":name", Value::String("Alice".to_string()), 1);
let mut writer = WalWriter::open_or_create(&path, SyncMode::Full).unwrap();
writer.append_entry(1, std::slice::from_ref(&fact)).unwrap();
let mut reader = WalReader::open(&path).unwrap();
let entries = reader.read_entries().unwrap();
assert_eq!(entries.len(), 1);
assert_eq!(entries[0].tx_count, 1);
assert_eq!(entries[0].facts.len(), 1);
assert_eq!(entries[0].facts[0].entity, fact.entity);
assert_eq!(entries[0].facts[0].attribute, fact.attribute);
assert_eq!(entries[0].facts[0].value, fact.value);
}
#[test]
fn test_wal_normal_mode_write_and_replay() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("test.wal");
let alice = Uuid::new_v4();
let fact = make_fact(alice, ":name", Value::String("Alice".to_string()), 1);
// Normal mode skips the per-write flush; the entry must still be
// durable-within-process (write_all()'d) and correctly replayable.
let mut writer = WalWriter::open_or_create(&path, SyncMode::Normal).unwrap();
writer.append_entry(1, std::slice::from_ref(&fact)).unwrap();
let mut reader = WalReader::open(&path).unwrap();
let entries = reader.read_entries().unwrap();
assert_eq!(entries.len(), 1);
assert_eq!(entries[0].tx_count, 1);
assert_eq!(entries[0].facts.len(), 1);
assert_eq!(entries[0].facts[0].entity, fact.entity);
}
#[test]
fn test_wal_multi_fact_entry_round_trip() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("test.wal");
let alice = Uuid::new_v4();
let facts = vec![
make_fact(alice, ":name", Value::String("Alice".to_string()), 1),
make_fact(alice, ":age", Value::Integer(30), 1),
];
let mut writer = WalWriter::open_or_create(&path, SyncMode::Full).unwrap();
writer.append_entry(1, &facts).unwrap();
let mut reader = WalReader::open(&path).unwrap();
let entries = reader.read_entries().unwrap();
assert_eq!(entries.len(), 1);
assert_eq!(entries[0].facts.len(), 2);
assert_eq!(entries[0].facts[0].entity, facts[0].entity);
assert_eq!(entries[0].facts[0].attribute, facts[0].attribute);
assert_eq!(entries[0].facts[0].value, facts[0].value);
assert_eq!(entries[0].facts[1].entity, facts[1].entity);
assert_eq!(entries[0].facts[1].attribute, facts[1].attribute);
assert_eq!(entries[0].facts[1].value, facts[1].value);
}
#[test]
fn test_wal_multiple_entries_round_trip() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("test.wal");
let alice = Uuid::new_v4();
let bob = Uuid::new_v4();
let mut writer = WalWriter::open_or_create(&path, SyncMode::Full).unwrap();
writer
.append_entry(
1,
&[make_fact(
alice,
":name",
Value::String("Alice".to_string()),
1,
)],
)
.unwrap();
writer
.append_entry(
2,
&[make_fact(bob, ":name", Value::String("Bob".to_string()), 2)],
)
.unwrap();
let mut reader = WalReader::open(&path).unwrap();
let entries = reader.read_entries().unwrap();
assert_eq!(entries.len(), 2);
assert_eq!(entries[0].tx_count, 1);
assert_eq!(entries[1].tx_count, 2);
}
#[test]
fn test_wal_reopen_and_append() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("test.wal");
let alice = Uuid::new_v4();
let bob = Uuid::new_v4();
// First open: create WAL and write entry with tx_count=1
let mut writer = WalWriter::open_or_create(&path, SyncMode::Full).unwrap();
writer
.append_entry(
1,
&[make_fact(
alice,
":name",
Value::String("Alice".to_string()),
1,
)],
)
.unwrap();
drop(writer);
// Second open: exercises the fallback branch (file already exists)
let mut writer = WalWriter::open_or_create(&path, SyncMode::Full).unwrap();
writer
.append_entry(
2,
&[make_fact(bob, ":name", Value::String("Bob".to_string()), 2)],
)
.unwrap();
drop(writer);
// Read back and verify both entries are present with correct tx_count values
let mut reader = WalReader::open(&path).unwrap();
let entries = reader.read_entries().unwrap();
assert_eq!(entries.len(), 2);
assert_eq!(entries[0].tx_count, 1);
assert_eq!(entries[1].tx_count, 2);
}
#[test]
fn test_wal_bad_magic_rejected() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("bad.wal");
// Write garbage header
std::fs::write(&path, b"XXXX\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00").unwrap();
let result = WalReader::open(&path);
assert!(result.is_err(), "bad magic should be rejected");
}
/// #308-class fix: a crash between `create_new` and the header write
/// finishing in `open_or_create` leaves a WAL file shorter than
/// `WAL_HEADER_SIZE`. No entry could ever have been appended at that
/// point (that requires a fully-open `WalWriter`), so this must be
/// treated as an empty WAL rather than a hard read error.
#[test]
fn test_wal_reader_tolerates_header_shorter_than_wal_header_size() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("short.wal");
// Simulates a kill mid-write_wal_header: only the magic made it out.
std::fs::write(&path, b"MWAL").unwrap();
let mut reader = WalReader::open(&path).unwrap();
let entries = reader.read_entries().unwrap();
assert!(
entries.is_empty(),
"a too-short WAL header must read back as empty, not error"
);
}
/// As above, but for the writer side: re-opening a WAL left too short
/// by a prior crash must re-initialize it with a fresh header instead
/// of failing `open_or_create`, and the WAL must be fully usable
/// afterward.
#[test]
fn test_wal_writer_reinitializes_header_shorter_than_wal_header_size() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("short.wal");
std::fs::write(&path, b"MW").unwrap();
let mut writer = WalWriter::open_or_create(&path, SyncMode::Full).unwrap();
let alice = Uuid::new_v4();
let fact = make_fact(alice, ":name", Value::String("Alice".to_string()), 1);
writer.append_entry(1, std::slice::from_ref(&fact)).unwrap();
drop(writer);
let mut reader = WalReader::open(&path).unwrap();
let entries = reader.read_entries().unwrap();
assert_eq!(entries.len(), 1, "re-initialized WAL must accept entries");
}
/// A completely empty (0-byte) WAL file -- the earliest possible point
/// in the crash window, right after `create_new` -- must be tolerated
/// the same way.
#[test]
fn test_wal_reader_tolerates_zero_byte_file() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("empty.wal");
std::fs::write(&path, []).unwrap();
let mut reader = WalReader::open(&path).unwrap();
let entries = reader.read_entries().unwrap();
assert!(entries.is_empty(), "a 0-byte WAL must read back as empty");
}
#[test]
fn test_wal_truncated_entry_stops_replay() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("test.wal");
let alice = Uuid::new_v4();
let fact = make_fact(alice, ":name", Value::String("Alice".to_string()), 1);
// Write a valid entry
let mut writer = WalWriter::open_or_create(&path, SyncMode::Full).unwrap();
writer.append_entry(1, &[fact]).unwrap();
drop(writer);
// Append garbage bytes after the valid entry to simulate a partial second write
let mut file = OpenOptions::new().append(true).open(&path).unwrap();
file.write_all(&[0xFF, 0xFF, 0xFF, 0xFF, 0x01]).unwrap(); // bad checksum prefix
drop(file);
let mut reader = WalReader::open(&path).unwrap();
let entries = reader.read_entries().unwrap();
// Only the valid first entry should be returned
assert_eq!(entries.len(), 1);
assert_eq!(entries[0].tx_count, 1);
}
#[test]
fn test_wal_delete_file() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("test.wal");
WalWriter::open_or_create(&path, SyncMode::Full).unwrap();
assert!(path.exists());
WalWriter::delete_file(&path).unwrap();
assert!(!path.exists());
}
#[test]
fn test_wal_fact_size_limit() {
use crate::graph::types::{Fact, Value};
use uuid::Uuid;
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("test.wal");
let mut writer = WalWriter::open_or_create(&path, SyncMode::Full).unwrap();
let entity = Uuid::new_v4();
let fact = Fact::new(
entity,
":test".to_string(),
Value::String("x".to_string()),
1,
);
// Write an entry with one fact
writer.append_entry(1, &[fact]).unwrap();
writer.file.sync_all().unwrap();
// Manually corrupt the WAL to have a fact larger than MAX_FACT_SIZE
let mut file = std::fs::OpenOptions::new().write(true).open(&path).unwrap();
file.seek(std::io::SeekFrom::End(-20)).unwrap();
// Overwrite the fact length to be huge
let huge_len: u32 = (10 * 1024 * 1024 + 1) as u32; // Just over MAX_FACT_SIZE
file.write_all(&huge_len.to_le_bytes()).unwrap();
drop(file);
// Try to read - should fail gracefully
let mut reader = WalReader::open(&path).unwrap();
let result = reader.read_entries();
assert!(
result.is_err() || result.unwrap().is_empty(),
"Should fail or return empty on corrupted large fact"
);
}
// ── #360: WAL-0xx error code regression tests ──────────────────────────
//
// These assert the exact code carried by `MinigrafError::from(err)` for
// each migrated call site, complementing `tests/error_codes_wal_test.rs`
// (which exercises the same WAL-001/002/003 paths through the public
// `Minigraf` API). WAL-004 and WAL-005 are documented as "practically
// unreachable" (WAL-004 needs a ~4 GB single fact; WAL-005 can never
// fail on a 64-bit target, where `usize` and `u64` are the same width)
// and have no dedicated trigger test here for that reason — they are
// still covered by `error::tests::registry_is_a_subset_of_error_reference_doc`
// and `error::tests::every_error_code_variant_has_a_registry_entry`.
#[test]
fn test_wal_bad_magic_error_code_is_wal_001() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("bad.wal");
std::fs::write(&path, b"XXXX\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00").unwrap();
let result = WalReader::open(&path);
let err = match result {
Err(e) => e,
Ok(_) => panic!("bad magic should be rejected"),
};
let minigraf_err: crate::error::MinigrafError = err.into();
assert_eq!(minigraf_err.code(), "WAL-001");
}
#[test]
fn test_wal_bad_version_error_code_is_wal_002() {
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("badversion.wal");
let mut header = [0u8; WAL_HEADER_SIZE];
header[0..4].copy_from_slice(&WAL_MAGIC);
header[4..8].copy_from_slice(&99u32.to_le_bytes());
std::fs::write(&path, header).unwrap();
let result = WalReader::open(&path);
let err = match result {
Err(e) => e,
Ok(_) => panic!("bad version should be rejected"),
};
let minigraf_err: crate::error::MinigrafError = err.into();
assert_eq!(minigraf_err.code(), "WAL-002");
}
#[test]
fn test_wal_fact_size_limit_error_code_is_wal_003() {
use crate::graph::types::{Fact, Value};
use uuid::Uuid;
let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("oversized.wal");
let mut writer = WalWriter::open_or_create(&path, SyncMode::Full).unwrap();
let entity = Uuid::new_v4();
let huge_string = "a".repeat(MAX_FACT_BYTES + 1000);
let fact = Fact::new(entity, ":test".to_string(), Value::String(huge_string), 1);
let result = writer.append_entry(1, &[fact]);
let err = result.expect_err("oversized fact should be rejected");
let minigraf_err: crate::error::MinigrafError = err.into();
assert_eq!(minigraf_err.code(), "WAL-003");
}
#[test]
fn test_wal_delete_directory_error_code_is_wal_006() {
let dir = tempfile::tempdir().unwrap();
// A directory at the WAL path, rather than a file, makes
// `std::fs::remove_file` fail regardless of permissions -- portable
// across platforms without needing a permission-denial trick.
let path = dir.path().join("not-a-file.wal");
std::fs::create_dir(&path).unwrap();
let result = WalWriter::delete_file(&path);
let err = result.expect_err("deleting a directory should fail");
let minigraf_err: crate::error::MinigrafError = err.into();
assert_eq!(minigraf_err.code(), "WAL-006");
std::fs::remove_dir(&path).unwrap();
}
}