Diagnostics

cobble check, cobble build, and the browser compiler run the same source-aware checks before compiling. They report:

• unsupported Python syntax;
• a missing : after a block header, unexpected or inconsistent indentation;
• unclosed delimiters and strings;
• duplicate functions and parameters, including across imported files or a compiled directory;
• expressions that produce no command;
• missing and circular imports, and diagnostics inside imported files;
• non-stdlib imports in the single-file browser compiler;
• undefined variables, functions, and stdlib modules;
• undefined, invalid, or unclosed {name} placeholders in raw commands;
• type mismatches;
• malformed datapack.* arguments, resource IDs, and tag entries.

Compilation then adds its own errors, such as loop expansion limits and JSON resource formats.

Output Format

Each diagnostic names its kind, points at the source, and adds a hint when there is one:

Error: missing-block-colon: Block headers must end with `:`
   ╭─[ main.cbl:1:8 ]
   │
 1 │ def f()
   │        ┬
   │        ╰── Block headers must end with `:`
   │
   │ Note: Add `:` at the end of the line before the indented block.
───╯

cobble check --json writes the same diagnostics to stdout as JSON with file, line, column, severity, kind, message, help, and a formatted text version. The browser compiler shows the same fields.

Kinds Listed Elsewhere

• Loop kinds such as unroll-limit-exceeded: For Loops.
• missing-stdlib-module: Standard Library Modules.
• datapack-resource-format: Data Pack Resources.
• resource-pack-* kinds: Resource Packs.
• temp-objective-reference in cobble migrate: Upgrading.