fsqlite 0.3.7

Public API facade
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186

//! GH#354 (bd-gy3a9): the persistent database-header field `default_cache_size`
//! (bytes 48..52, big-endian `i32`) must be `0` ("unset") on a freshly created
//! database, matching stock SQLite. The engine previously stamped its *runtime*
//! default (`-2000`) there, so every fsqlite-created file looked like the client
//! had explicitly requested a cache size it never asked for — a file-format
//! divergence that breaks any consumer pinning/preserving header fields.
//!
//! Both halves the issue requests are verified:
//!   1. (bd-gy3a9) Create a database without touching the pragma -> bytes 48..52
//!      == 0, and stock still reports -2000 at the pragma surface.
//!   2. (bd-n7eih) An explicit `PRAGMA default_cache_size=N` persists to bytes
//!      48..52 (stored as abs(N), matching stock's sqlite3AbsInt32), survives
//!      reopen, and is echoed in-session — cross-checked against the C-SQLite
//!      file-format oracle.

use fsqlite::Connection;

/// Read header bytes 48..52 of a SQLite database file as a big-endian `i32`.
fn header_default_cache_size(path: &str) -> i32 {
    let bytes = std::fs::read(path).expect("read database file");
    assert!(
        bytes.len() >= 52,
        "database file shorter than the 100-byte header: {} bytes",
        bytes.len()
    );
    assert_eq!(
        &bytes[..16],
        b"SQLite format 3\0",
        "file is not a stock SQLite image"
    );
    i32::from_be_bytes([bytes[48], bytes[49], bytes[50], bytes[51]])
}

#[test]
fn fresh_database_leaves_default_cache_size_unset_gh354() {
    asupersync::test_utils::run_test(|| async {
        let dir = tempfile::tempdir().expect("tempdir");
        let db = dir
            .path()
            .join("hdr_dcs.sqlite")
            .to_string_lossy()
            .into_owned();

        let conn = Connection::open(&db).await.expect("open database");
        conn.execute("CREATE TABLE t(a INTEGER PRIMARY KEY, b TEXT)")
            .await
            .expect("create table");
        conn.execute("INSERT INTO t VALUES (1, 'x')")
            .await
            .expect("insert row");
        conn.close().await.expect("close database");

        let stored = header_default_cache_size(&db);
        assert_eq!(
            stored, 0,
            "fresh database must carry default_cache_size=0 in header bytes 48..52, \
             not the runtime default; stock writes 0 unless PRAGMA default_cache_size is set"
        );

        // The written image must also be readable by the C-SQLite oracle.
        let oracle = rusqlite::Connection::open(&db).expect("oracle opens database");
        let oracle_dcs: i64 = oracle
            .query_row("PRAGMA default_cache_size", [], |row| row.get(0))
            .expect("oracle reads default_cache_size");
        // Stock reports the runtime default (-2000) at the pragma surface even
        // though the persisted field is 0.
        assert_eq!(
            oracle_dcs, -2000,
            "oracle runtime default_cache_size should be the compiled default"
        );
    });
}

/// Read header bytes 48..52 of a stock database written by rusqlite with the
/// given `PRAGMA default_cache_size` assignment, as the file-format oracle.
fn oracle_header_default_cache_size(dir: &std::path::Path, name: &str, assign: &str) -> i32 {
    let path = dir.join(name);
    let conn = rusqlite::Connection::open(&path).expect("oracle open");
    conn.execute_batch(&format!(
        "PRAGMA default_cache_size={assign}; CREATE TABLE t(a);"
    ))
    .expect("oracle set + create");
    drop(conn);
    header_default_cache_size(path.to_str().expect("path utf8"))
}

#[test]
fn explicit_default_cache_size_pragma_persists_gh354() {
    asupersync::test_utils::run_test(|| async {
        let dir = tempfile::tempdir().expect("tempdir");
        let db = dir
            .path()
            .join("hdr_dcs_explicit.sqlite")
            .to_string_lossy()
            .into_owned();

        let conn = Connection::open(&db).await.expect("open database");
        conn.execute("PRAGMA default_cache_size=5000")
            .await
            .expect("set default_cache_size");
        // In-session the bare query echoes the set value (matching stock).
        let in_session = conn
            .query("PRAGMA default_cache_size")
            .await
            .expect("query default_cache_size in session");
        assert_eq!(
            in_session[0].values()[0].clone(),
            fsqlite::SqliteValue::Integer(5000),
            "in-session PRAGMA default_cache_size must echo the set value"
        );
        conn.execute("CREATE TABLE t(a INTEGER PRIMARY KEY)")
            .await
            .expect("create table");
        conn.close().await.expect("close database");

        let stored = header_default_cache_size(&db);
        assert_eq!(
            stored, 5000,
            "explicit PRAGMA default_cache_size=5000 must persist to header bytes 48..52"
        );
        assert_eq!(
            stored,
            oracle_header_default_cache_size(dir.path(), "oracle_5000.db", "5000"),
            "header value must match the C-SQLite oracle for default_cache_size=5000"
        );

        // And it must survive reopen.
        let reopened = Connection::open(&db).await.expect("reopen database");
        let rows = reopened
            .query("PRAGMA default_cache_size")
            .await
            .expect("query default_cache_size");
        assert_eq!(
            rows[0].values()[0].clone(),
            fsqlite::SqliteValue::Integer(5000),
            "explicit default_cache_size must survive reopen"
        );
        reopened.close().await.expect("close reopened");
    });
}

#[test]
fn default_cache_size_negative_is_stored_as_abs_gh354() {
    asupersync::test_utils::run_test(|| async {
        // Stock stores abs(N) as a page count (legacy sqlite3AbsInt32): a
        // negative assignment persists positive. `-3000` -> header 3000.
        let dir = tempfile::tempdir().expect("tempdir");
        let db = dir
            .path()
            .join("hdr_dcs_neg.sqlite")
            .to_string_lossy()
            .into_owned();

        let conn = Connection::open(&db).await.expect("open database");
        conn.execute("PRAGMA default_cache_size=-3000")
            .await
            .expect("set default_cache_size");
        conn.execute("CREATE TABLE t(a)")
            .await
            .expect("create table");
        conn.close().await.expect("close database");

        let stored = header_default_cache_size(&db);
        assert_eq!(
            stored, 3000,
            "PRAGMA default_cache_size=-3000 must persist as abs -> 3000"
        );
        assert_eq!(
            stored,
            oracle_header_default_cache_size(dir.path(), "oracle_neg.db", "-3000"),
            "abs-store behaviour must match the C-SQLite oracle"
        );

        let reopened = Connection::open(&db).await.expect("reopen database");
        let rows = reopened
            .query("PRAGMA default_cache_size")
            .await
            .expect("query default_cache_size");
        assert_eq!(
            rows[0].values()[0].clone(),
            fsqlite::SqliteValue::Integer(3000),
            "abs-stored default_cache_size must survive reopen"
        );
        reopened.close().await.expect("close reopened");
    });
}