+ "markdownDescription": "Configure a command that rust-analyzer can invoke to\nobtain configuration.\n\nThis is an alternative to manually generating\n`rust-project.json`: it enables rust-analyzer to generate\nrust-project.json on the fly, and regenerate it when\nswitching or modifying projects.\n\nThis is an object with three fields:\n\n* `command`: the shell command to invoke\n\n* `filesToWatch`: which build system-specific files should\nbe watched to trigger regenerating the configuration\n\n* `progressLabel`: the name of the command, used in\nprogress indicators in the IDE\n\nHere's an example of a valid configuration:\n\n```json\n\"rust-analyzer.workspace.discoverConfig\": {\n \"command\": [\n \"rust-project\",\n \"develop-json\",\n \"{arg}\"\n ],\n \"progressLabel\": \"buck2/rust-project\",\n \"filesToWatch\": [\n \"BUCK\"\n ]\n}\n```\n\n## Argument Substitutions\n\nIf `command` includes the argument `{arg}`, that argument will be substituted\nwith the JSON-serialized form of the following enum:\n\n```norun\n#[derive(PartialEq, Clone, Debug, Serialize)]\n#[serde(rename_all = \"camelCase\")]\npub enum DiscoverArgument {\n Path(AbsPathBuf),\n Buildfile(AbsPathBuf),\n}\n```\n\nrust-analyzer will use the path invocation to find and\ngenerate a `rust-project.json` and therefore a\nworkspace. Example:\n\n\n```norun\nrust-project develop-json '{ \"path\": \"myproject/src/main.rs\" }'\n```\n\nrust-analyzer will use build file invocations to update an\nexisting workspace. Example:\n\nOr with a build file and the configuration above:\n\n```norun\nrust-project develop-json '{ \"buildfile\": \"myproject/BUCK\" }'\n```\n\nAs a reference for implementors, buck2's `rust-project`\nwill likely be useful:\n<https://github.com/facebook/buck2/tree/main/integrations/rust-project>.\n\n## Discover Command Output\n\n**Warning**: This format is provisional and subject to change.\n\nThe discover command should output JSON objects, one per\nline (JSONL format). These objects should correspond to\nthis Rust data type:\n\n```norun\n#[derive(Debug, Clone, Deserialize, Serialize)]\n#[serde(tag = \"kind\")]\n#[serde(rename_all = \"snake_case\")]\nenum DiscoverProjectData {\n Finished { buildfile: Utf8PathBuf, project: ProjectJsonData },\n Error { error: String, source: Option<String> },\n Progress { message: String },\n}\n```\n\nFor example, a progress event:\n\n```json\n{\"kind\":\"progress\",\"message\":\"generating rust-project.json\"}\n```\n\nA finished event can look like this (expanded and\ncommented for readability):\n\n```json\n{\n // the internally-tagged representation of the enum.\n \"kind\": \"finished\",\n // the file used by a non-Cargo build system to define\n // a package or target.\n \"buildfile\": \"rust-analyzer/BUCK\",\n // the contents of a rust-project.json, elided for brevity\n \"project\": {\n \"sysroot\": \"foo\",\n \"crates\": []\n }\n}\n```\n\nOnly the finished event is required, but the other\nvariants are encouraged to give users more feedback about\nprogress or errors.",