linter: Oxc server crashes in VS Code when opening a .astro with pascalCase filename

[JamesJosephFinn]

What version of Oxlint are you using?

1.23.0

What command did you run?

pnpm run lint defined as oxlint . --type-aware --format=stylish --report-unused-disable-directives

What does your .oxlintrc.json config file look like?

{
	// schema kept here for reference. not needed with vscode extension.
	// "$schema": "https://raw.githubusercontent.com/oxc-project/oxc/main/npm/oxlint/configuration_schema.json",
	"ignorePatterns": [
		".astro/",
		"dist/",
		"node_modules/",
		".git/",
		".github/",
		".vscode/"
	],
	"categories": {
		"correctness": "error",
		"perf": "warn",
		"suspicious": "warn",
		"pedantic": "warn",
		"style": "warn",
		"nursery": "off",
		"restriction": "off"
	},
	"plugins": [
		"eslint",
		"typescript",
		"unicorn",
		"oxc",
		"import",
		"jsx-a11y",
		"node",
		"promise",
		"regex"
	],
	"rules": {
		"unicorn/filename-case": [
			"warn",
			{
				"cases": {
					"pascalCase": true, // components / layouts
					"kebabCase": true // everything else
				}
			}
		]
	},
	"overrides": [
		{
			"files": ["**/*.{jsx,tsx,mjsx,mtsx}"],
			"plugins": ["react", "react-perf"]
		},
		{
			"files": ["**/*.test.{js,ts}", "tests/**"],
			"plugins": ["vitest"]
		}
	]
}

What happened?

In VS Code, without the above rules: {} object for rule unicorn/filename-case, attempting to open, for example, /src/components/Component.astro crashes the Oxc server, and it needs to be restarted. After setting the rule as above, the file can be opened and parsed in VS Code by Oxc without issue.

Curiously, without the rule being set, opening of pascalCase files in the /src/layouts dir, e.g. /src/layouts/Layout.astro, does not crash the Oxc server. i.e., the issue is local only to the /src/components dir.

The CLI does not crash, but it mis-reports the warnings; i.e., without the rule being set, it emits a warning for /src/components/Component.astro, but not for src/layouts/Layout.astro. When adding the rule, the CLI behaves as expected, i.e. it emits no warnings for either file.

[camc314]

if possible could you share the logs from the language server? ( i only need the logs from when it crashes)

[JamesJosephFinn]

Certainly. Here you go sir:

2025-10-13 17:56:22.493 [info] 
thread 'main' panicked at crates/oxc_language_server/src/linter/error_with_position.rs:268:27:
slice index starts at 4 but ends at 3
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

2025-10-13 17:56:22.493 [info] [Error - 5:56:22 PM] Server process exited with signal SIGABRT.
2025-10-13 17:56:22.494 [info] [Info  - 5:56:22 PM] Connection to server got closed. Server will restart.
2025-10-13 17:56:22.494 [info] true
2025-10-13 17:56:22.500 [info] [2025-10-13T21:56:22Z INFO  oxc_language_server::backend] initialize: Some([WorkspaceOption { workspace_uri: Uri(Uri { scheme: Some("file"), authority: Some(Authority { userinfo: None, host: Host { text: "", data: RegName("") }, port: None }), path: "/Volumes/Catacomb/Polycarp%20Systems/Novus%20Ordo%20Watch/Website/App", query: None, fragment: None }), options: Options { lint: LintOptions { run: OnType, config_path: None, ts_config_path: None, unused_disable_directives: Warn, type_aware: true, flags: {} }, format: FormatOptions { experimental: false, config_path: None } } }])
[2025-10-13T21:56:22Z INFO  oxc_language_server::backend] language server version: 1.23.0

2025-10-13 17:56:22.508 [info] 
thread 'main' panicked at crates/oxc_language_server/src/linter/error_with_position.rs:268:27:
slice index starts at 4 but ends at 3
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

2025-10-13 17:56:22.508 [info] [Info  - 5:56:22 PM] Connection to server got closed. Server will restart.
2025-10-13 17:56:22.508 [info] true
2025-10-13 17:56:22.509 [info] [Error - 5:56:22 PM] Server process exited with signal SIGABRT.
2025-10-13 17:56:22.512 [info] [2025-10-13T21:56:22Z INFO  oxc_language_server::backend] initialize: Some([WorkspaceOption { workspace_uri: Uri(Uri { scheme: Some("file"), authority: Some(Authority { userinfo: None, host: Host { text: "", data: RegName("") }, port: None }), path: "/Volumes/Catacomb/Polycarp%20Systems/Novus%20Ordo%20Watch/Website/App", query: None, fragment: None }), options: Options { lint: LintOptions { run: OnType, config_path: None, ts_config_path: None, unused_disable_directives: Warn, type_aware: true, flags: {} }, format: FormatOptions { experimental: false, config_path: None } } }])
[2025-10-13T21:56:22Z INFO  oxc_language_server::backend] language server version: 1.23.0

2025-10-13 17:56:22.519 [info] 
thread 'main' panicked at crates/oxc_language_server/src/linter/error_with_position.rs:268:27:
slice index starts at 4 but ends at 3
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

2025-10-13 17:56:22.520 [info] [Error - 5:56:22 PM] Server process exited with signal SIGABRT.
2025-10-13 17:56:22.520 [info] [Info  - 5:56:22 PM] Connection to server got closed. Server will restart.
2025-10-13 17:56:22.520 [info] true
2025-10-13 17:56:22.523 [info] [2025-10-13T21:56:22Z INFO  oxc_language_server::backend] initialize: Some([WorkspaceOption { workspace_uri: Uri(Uri { scheme: Some("file"), authority: Some(Authority { userinfo: None, host: Host { text: "", data: RegName("") }, port: None }), path: "/Volumes/Catacomb/Polycarp%20Systems/Novus%20Ordo%20Watch/Website/App", query: None, fragment: None }), options: Options { lint: LintOptions { run: OnType, config_path: None, ts_config_path: None, unused_disable_directives: Warn, type_aware: true, flags: {} }, format: FormatOptions { experimental: false, config_path: None } } }])
[2025-10-13T21:56:22Z INFO  oxc_language_server::backend] language server version: 1.23.0

2025-10-13 17:56:22.550 [info] 
thread 'main' panicked at crates/oxc_language_server/src/linter/error_with_position.rs:268:27:
slice index starts at 4 but ends at 3
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

2025-10-13 17:56:22.551 [info] [Error - 5:56:22 PM] Server process exited with signal SIGABRT.
2025-10-13 17:56:22.551 [info] [Info  - 5:56:22 PM] Connection to server got closed. Server will restart.
2025-10-13 17:56:22.551 [info] true
2025-10-13 17:56:22.559 [info] [2025-10-13T21:56:22Z INFO  oxc_language_server::backend] initialize: Some([WorkspaceOption { workspace_uri: Uri(Uri { scheme: Some("file"), authority: Some(Authority { userinfo: None, host: Host { text: "", data: RegName("") }, port: None }), path: "/Volumes/Catacomb/Polycarp%20Systems/Novus%20Ordo%20Watch/Website/App", query: None, fragment: None }), options: Options { lint: LintOptions { run: OnType, config_path: None, ts_config_path: None, unused_disable_directives: Warn, type_aware: true, flags: {} }, format: FormatOptions { experimental: false, config_path: None } } }])
[2025-10-13T21:56:22Z INFO  oxc_language_server::backend] language server version: 1.23.0

2025-10-13 17:56:22.566 [info] 
thread 'main' panicked at crates/oxc_language_server/src/linter/error_with_position.rs:268:27:
slice index starts at 4 but ends at 3
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

2025-10-13 17:56:22.566 [info] [Info  - 5:56:22 PM] Connection to server got closed. Server will restart.
2025-10-13 17:56:22.566 [info] true
2025-10-13 17:56:22.567 [info] [Error - 5:56:22 PM] Server process exited with signal SIGABRT.
2025-10-13 17:56:22.573 [info] [2025-10-13T21:56:22Z INFO  oxc_language_server::backend] initialize: Some([WorkspaceOption { workspace_uri: Uri(Uri { scheme: Some("file"), authority: Some(Authority { userinfo: None, host: Host { text: "", data: RegName("") }, port: None }), path: "/Volumes/Catacomb/Polycarp%20Systems/Novus%20Ordo%20Watch/Website/App", query: None, fragment: None }), options: Options { lint: LintOptions { run: OnType, config_path: None, ts_config_path: None, unused_disable_directives: Warn, type_aware: true, flags: {} }, format: FormatOptions { experimental: false, config_path: None } } }])
[2025-10-13T21:56:22Z INFO  oxc_language_server::backend] language server version: 1.23.0

2025-10-13 17:56:22.580 [info] 
thread 'main' panicked at crates/oxc_language_server/src/linter/error_with_position.rs:268:27:
slice index starts at 4 but ends at 3
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

2025-10-13 17:56:22.581 [info] [Info  - 5:56:22 PM] Connection to server got closed. Server will restart.
2025-10-13 17:56:22.581 [info] true
2025-10-13 17:56:22.581 [info] [Error - 5:56:22 PM] Server process exited with signal SIGABRT.
2025-10-13 17:56:22.584 [info] [2025-10-13T21:56:22Z INFO  oxc_language_server::backend] initialize: Some([WorkspaceOption { workspace_uri: Uri(Uri { scheme: Some("file"), authority: Some(Authority { userinfo: None, host: Host { text: "", data: RegName("") }, port: None }), path: "/Volumes/Catacomb/Polycarp%20Systems/Novus%20Ordo%20Watch/Website/App", query: None, fragment: None }), options: Options { lint: LintOptions { run: OnType, config_path: None, ts_config_path: None, unused_disable_directives: Warn, type_aware: true, flags: {} }, format: FormatOptions { experimental: false, config_path: None } } }])
[2025-10-13T21:56:22Z INFO  oxc_language_server::backend] language server version: 1.23.0

2025-10-13 17:56:22.592 [info] 
thread 'main' panicked at crates/oxc_language_server/src/linter/error_with_position.rs:268:27:
slice index starts at 4 but ends at 3
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

2025-10-13 17:56:22.592 [info] [Info  - 5:56:22 PM] Connection to server got closed. Server will restart.
2025-10-13 17:56:22.592 [info] true
2025-10-13 17:56:22.593 [info] [Error - 5:56:22 PM] Server process exited with signal SIGABRT.
2025-10-13 17:56:22.611 [info] [2025-10-13T21:56:22Z INFO  oxc_language_server::backend] initialize: Some([WorkspaceOption { workspace_uri: Uri(Uri { scheme: Some("file"), authority: Some(Authority { userinfo: None, host: Host { text: "", data: RegName("") }, port: None }), path: "/Volumes/Catacomb/Polycarp%20Systems/Novus%20Ordo%20Watch/Website/App", query: None, fragment: None }), options: Options { lint: LintOptions { run: OnType, config_path: None, ts_config_path: None, unused_disable_directives: Warn, type_aware: true, flags: {} }, format: FormatOptions { experimental: false, config_path: None } } }])
[2025-10-13T21:56:22Z INFO  oxc_language_server::backend] language server version: 1.23.0

2025-10-13 17:56:22.617 [info] 
thread 'main' panicked at crates/oxc_language_server/src/linter/error_with_position.rs:268:27:
slice index starts at 4 but ends at 3
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

2025-10-13 17:56:22.620 [info] [Info  - 5:56:22 PM] Connection to server got closed. Server will restart.
2025-10-13 17:56:22.620 [info] true
2025-10-13 17:56:22.621 [info] [Error - 5:56:22 PM] Server process exited with signal SIGABRT.
2025-10-13 17:56:22.641 [info] [2025-10-13T21:56:22Z INFO  oxc_language_server::backend] initialize: Some([WorkspaceOption { workspace_uri: Uri(Uri { scheme: Some("file"), authority: Some(Authority { userinfo: None, host: Host { text: "", data: RegName("") }, port: None }), path: "/Volumes/Catacomb/Polycarp%20Systems/Novus%20Ordo%20Watch/Website/App", query: None, fragment: None }), options: Options { lint: LintOptions { run: OnType, config_path: None, ts_config_path: None, unused_disable_directives: Warn, type_aware: true, flags: {} }, format: FormatOptions { experimental: false, config_path: None } } }])
[2025-10-13T21:56:22Z INFO  oxc_language_server::backend] language server version: 1.23.0

2025-10-13 17:56:22.647 [info] 
thread 'main' panicked at crates/oxc_language_server/src/linter/error_with_position.rs:268:27:
slice index starts at 4 but ends at 3
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

2025-10-13 17:56:22.648 [info] [Info  - 5:56:22 PM] Connection to server got closed. Server will restart.
2025-10-13 17:56:22.648 [info] true
2025-10-13 17:56:22.649 [info] [Error - 5:56:22 PM] Server process exited with signal SIGABRT.
2025-10-13 17:56:22.669 [info] [2025-10-13T21:56:22Z INFO  oxc_language_server::backend] initialize: Some([WorkspaceOption { workspace_uri: Uri(Uri { scheme: Some("file"), authority: Some(Authority { userinfo: None, host: Host { text: "", data: RegName("") }, port: None }), path: "/Volumes/Catacomb/Polycarp%20Systems/Novus%20Ordo%20Watch/Website/App", query: None, fragment: None }), options: Options { lint: LintOptions { run: OnType, config_path: None, ts_config_path: None, unused_disable_directives: Warn, type_aware: true, flags: {} }, format: FormatOptions { experimental: false, config_path: None } } }])
[2025-10-13T21:56:22Z INFO  oxc_language_server::backend] language server version: 1.23.0

2025-10-13 17:56:22.676 [info] 
thread 'main' panicked at crates/oxc_language_server/src/linter/error_with_position.rs:268:27:
slice index starts at 4 but ends at 3
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

2025-10-13 17:56:22.676 [info] [Info  - 5:56:22 PM] Connection to server got closed. Server will restart.
2025-10-13 17:56:22.676 [info] true
2025-10-13 17:56:22.677 [info] [Error - 5:56:22 PM] Server process exited with signal SIGABRT.
2025-10-13 17:56:22.695 [info] [2025-10-13T21:56:22Z INFO  oxc_language_server::backend] initialize: Some([WorkspaceOption { workspace_uri: Uri(Uri { scheme: Some("file"), authority: Some(Authority { userinfo: None, host: Host { text: "", data: RegName("") }, port: None }), path: "/Volumes/Catacomb/Polycarp%20Systems/Novus%20Ordo%20Watch/Website/App", query: None, fragment: None }), options: Options { lint: LintOptions { run: OnType, config_path: None, ts_config_path: None, unused_disable_directives: Warn, type_aware: true, flags: {} }, format: FormatOptions { experimental: false, config_path: None } } }])
[2025-10-13T21:56:22Z INFO  oxc_language_server::backend] language server version: 1.23.0

2025-10-13 17:56:22.701 [info] 
thread 'main' panicked at crates/oxc_language_server/src/linter/error_with_position.rs:268:27:
slice index starts at 4 but ends at 3
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

2025-10-13 17:56:22.702 [info] [Error - 5:56:22 PM] The oxc server crashed 5 times in the last 3 minutes. The server will not be restarted. See the output for more information.
2025-10-13 17:56:22.702 [info] [Error - 5:56:22 PM] Server process exited with signal SIGABRT.

[Sysix]

It is fixed for the next release of the language server / VS Code extension,
thanks for reporting!

[JamesJosephFinn]

@Sysix thank you for helping make such a wonderful DX linter!!