easy implementation, sqlite claims it is a noop now
"This pragma no longer functions. It has become a no-op. The capabilities
formerly provided by PRAGMA legacy_file_format are now available using
the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option to the sqlite3_db_config()
C-language interface."
Fix is to track the state of encountering error in the `Parser` struct and set it to true whereever/whenever
we encounter an error. And the beginning of the next() we return `Ok(None)` to signal to `FallibleIterator` that we should stop parsing.
Fixes https://github.com/tursodatabase/limbo/issues/865
The pragma list will only grow. The strum crate can be used to:
* automatically convert to string from enum
* automatically convert to enum from string
* implement an iterator over all elements of the enum
Both () and = variants covered. It is important to make sure that
the transaction is a read transaction, so we cannot hide all that logic
inside update_pragma, and have to make our decision before that.
I noticed that the parse errors were a bit hard to read - only the
nearest token and the line/col offsets were printed.
I made a first attempt at improving the errors using
[miette](https://github.com/zkat/miette).
- Added derive for `miette::Diagnostic` to both the parser's error type
and LimboError.
- Added miette dependency to both sqlite3_parser and core. The `fancy`
feature is only enabled for the CLI. So the overhead on the libraries
(core, parser) should be minimal.
Some future improvements that can be made further:
- Add spans to AST nodes so that errors can better point to the correct
token. See upstream issue: https://github.com/gwenn/lemon-rs/issues/33
- Construct more errors with offset information. I noticed that most
parser errors are constructed with `None` as the offset.
- The messages are a bit redundant (example "syntax error at (1, 6)").
This can improved.
Comparisons.
Before:
```
❯ cargo run --package limbo --bin limbo database.db --output-mode pretty
...
limbo> selet * from a;
[2025-01-05T11:22:55Z ERROR sqlite3Parser] near "Token([115, 101, 108, 101, 116])": syntax error
Parse error: near "selet": syntax error at (1, 6)
```
<img width="969" alt="image" src="https://github.com/user-
attachments/assets/82651a77-f5ac-4eee-b208-88c6ea7fc9b7" />
After:
```
❯ cargo run --package limbo --bin limbo database.db --output-mode pretty
...
limbo> selet * from a;
[2025-01-05T12:25:52Z ERROR sqlite3Parser] near "Token([115, 101, 108, 101, 116])": syntax error
× near "selet": syntax error at (1, 6)
╭────
1 │ selet * from a
· ▲
· ╰── syntax error
╰────
```
<img width="980" alt="image" src="https://github.com/user-
attachments/assets/747a90e5-5085-41f9-b0fe-25864179ca35" />
Closes#618
I noticed that the parse errors were a bit hard to read - only the nearest token and the line/col offsets were printed.
I made a first attempt at improving the errors using [miette](https://github.com/zkat/miette).
- Added derive for `miette::Diagnostic` to both the parser's error type and LimboError.
- Added miette dependency to both sqlite3_parser and core. The `fancy` feature is only enabled for CLI.
Some future improvements that can be made further:
- Add spans to AST nodes so that errors can better point to the correct token. See upstream issue: https://github.com/gwenn/lemon-rs/issues/33
- Construct more errors with offset information. I noticed that most parser errors are constructed with `None` as the offset.
Comparisons.
Before:
```
❯ cargo run --package limbo --bin limbo database.db --output-mode pretty
...
limbo> selet * from a;
[2025-01-05T11:22:55Z ERROR sqlite3Parser] near "Token([115, 101, 108, 101, 116])": syntax error
Parse error: near "selet": syntax error at (1, 6)
```
After:
```
❯ cargo run --package limbo --bin limbo database.db --output-mode pretty
...
limbo> selet * from a;
[2025-01-05T12:25:52Z ERROR sqlite3Parser] near "Token([115, 101, 108, 101, 116])": syntax error
× near "selet": syntax error at (1, 6)
╭────
1 │ selet * from a
· ▲
· ╰── syntax error
╰────
```
This change refactors how PRAGMA statements are handled, introducing a
more organized and extensible structure to simplify adding new PRAGMA
properties in the future.
Previously, only the `cache_size` PRAGMA was supported. With this
update, support for the `journal_mode` PRAGMA has been added.
