Add support for all file extensions (including files without extensions) and folders

AGENTS.md

@@ -36,7 +36,7 @@ If `lat search` fails because no API key is configured, explain to the user that
 
 - **Section ids**: `lat.md/path/to/file#Heading#SubHeading` — full form uses project-root-relative path (e.g. `lat.md/tests/search#RAG Replay Tests`). Short form uses bare file name when unique (e.g. `search#RAG Replay Tests`, `cli#search#Indexing`).
 - **Wiki links**: `[[target]]` or `[[target|alias]]` — cross-references between sections. Can also reference source code: `[[src/foo.ts#myFunction]]`.
-- **Source code links**: Wiki links in `lat.md/` files can reference functions, classes, constants, and methods in TypeScript/JavaScript/Python/Rust/Go/C files. Use the full path: `[[src/config.ts#getConfigDir]]`, `[[src/server.ts#App#listen]]` (class method), `[[lib/utils.py#parse_args]]`, `[[src/lib.rs#Greeter#greet]]` (Rust impl method), `[[src/app.go#Greeter#Greet]]` (Go method), `[[src/app.h#Greeter]]` (C struct). `lat check` validates these exist.
+- **Source code links**: Wiki links in `lat.md/` files can reference functions, classes, constants, and methods in TypeScript/JavaScript/Python/Rust/Go/C files. Use the full path: `[[src/config.ts#getConfigDir]]`, `[[src/server.ts#App#listen]]` (class method), `[[lib/utils.py#parse_args]]`, `[[src/lib.rs#Greeter#greet]]` (Rust impl method), `[[src/app.go#Greeter#Greet]]` (Go method), `[[src/app.h#Greeter]]` (C struct). Can also link to folders (`[[src/components]]`) or files with any extension (`[[schema.sql]]`) — these are validated to exist. Symbol references (`#`) only work for supported extensions. `lat check` validates these exist.
 - **Code refs**: `// @lat: [[section-id]]` (JS/TS/Rust/Go/C) or `# @lat: [[section-id]]` (Python) — ties source code to concepts
 
 # Test specs

CLAUDE.md

@@ -36,7 +36,7 @@ If `lat search` fails because no API key is configured, explain to the user that
 
 - **Section ids**: `lat.md/path/to/file#Heading#SubHeading` — full form uses project-root-relative path (e.g. `lat.md/tests/search#RAG Replay Tests`). Short form uses bare file name when unique (e.g. `search#RAG Replay Tests`, `cli#search#Indexing`).
 - **Wiki links**: `[[target]]` or `[[target|alias]]` — cross-references between sections. Can also reference source code: `[[src/foo.ts#myFunction]]`.
-- **Source code links**: Wiki links in `lat.md/` files can reference functions, classes, constants, and methods in TypeScript/JavaScript/Python/Rust/Go/C files. Use the full path: `[[src/config.ts#getConfigDir]]`, `[[src/server.ts#App#listen]]` (class method), `[[lib/utils.py#parse_args]]`, `[[src/lib.rs#Greeter#greet]]` (Rust impl method), `[[src/app.go#Greeter#Greet]]` (Go method), `[[src/app.h#Greeter]]` (C struct). `lat check` validates these exist.
+- **Source code links**: Wiki links in `lat.md/` files can reference functions, classes, constants, and methods in TypeScript/JavaScript/Python/Rust/Go/C files. Use the full path: `[[src/config.ts#getConfigDir]]`, `[[src/server.ts#App#listen]]` (class method), `[[lib/utils.py#parse_args]]`, `[[src/lib.rs#Greeter#greet]]` (Rust impl method), `[[src/app.go#Greeter#Greet]]` (Go method), `[[src/app.h#Greeter]]` (C struct). Can also link to folders (`[[src/components]]`) or files with any extension (`[[schema.sql]]`) — these are validated to exist. Symbol references (`#`) only work for supported extensions. `lat check` validates these exist.
 - **Code refs**: `// @lat: [[section-id]]` (JS/TS/Rust/Go/C) or `# @lat: [[section-id]]` (Python) — ties source code to concepts
 
 # Test specs

lat.md/markdown.md

@@ -32,17 +32,25 @@ Resolution is handled by [[src/lattice.ts#resolveRef]]. See [[parser#Short Ref R
 
 ### Source Code Links
 
-Wiki links can reference symbols in TypeScript, JavaScript, Python, Rust, Go, and C source files:
+Wiki links can point to any file or folder in the project, and — for supported languages — to individual symbols within a source file.
+
+**Symbol targets** (use `#` to select a symbol inside a file):
 
 - **`[[src/config.ts#getConfigDir]]`** — the `getConfigDir` function in `src/config.ts`
-- **`[[src/server.ts#App#listen]]`** — the `listen` method on class `App` in `src/server.ts`
+- **`[[src/server.ts#App#listen]]`** — the `listen` method on class `App`
 - **`[[src/lib.rs#Greeter#greet]]`** — the `greet` method on struct `Greeter` in Rust
 - **`[[src/app.go#Greeter#Greet]]`** — the `Greet` method on type `Greeter` in Go
 - **`[[src/app.h#Greeter]]`** — the `Greeter` struct in a C header
 - **`[[src/app.h#Greeter#prefix]]`** — the `prefix` field of struct `Greeter` in C
-- **`[[src/config.ts]]`** — link to the file itself (no symbol)
 
-Supported extensions: `.ts`, `.tsx`, `.js`, `.jsx`, `.py`, `.rs`, `.go`, `.c`, `.h`.
+**Path targets** (no `#` — any file or folder in the project):
+
+- **`[[src/config.ts]]`** — a source file, linked without picking a symbol
+- **`[[src/schema.sql]]`** — a file with any extension
+- **`[[docs/CHANGELOG]]`** — a file with no extension
+- **`[[src/components]]`** — a folder
+
+`lat check` verifies path targets exist on disk and symbol targets resolve to a real definition. Symbol targets (`#`) are only supported for these extensions: `.ts`, `.tsx`, `.js`, `.jsx`, `.py`, `.rs`, `.go`, `.c`, `.h`. Using `#` with any other extension (e.g. `[[schema.sql#foo]]`) is an error.
 
 Python symbols: functions, classes, methods, module-level variables. Decorated definitions (`@decorator`) are unwrapped transparently — `[[file.py#my_func]]` resolves whether or not `my_func` has decorators, and `# @lat:` comments placed between decorators and the `def`/`class` line are scanned normally.
 

src/cli/check.ts

@@ -1,22 +1,21 @@
-import { readFile } from 'node:fs/promises';
 import { existsSync } from 'node:fs';
+import { readFile } from 'node:fs/promises';
 import { basename, dirname, extname, join, relative } from 'node:path';
+import { scanCodeRefs } from '../code-refs.js';
+import type { CmdContext, CmdResult, Styler } from '../context.js';
+import { INIT_VERSION, readInitVersion } from '../init-version.js';
 import {
-  listLatticeFiles,
-  loadAllSections,
+  buildFileIndex,
   extractRefs,
   flattenSections,
+  listLatticeFiles,
+  loadAllSections,
   parseFrontmatter,
   parseSections,
-  buildFileIndex,
   resolveRef,
-  type Section,
 } from '../lattice.js';
-import { scanCodeRefs } from '../code-refs.js';
 import { SOURCE_EXTENSIONS, clearSymbolCache } from '../source-parser.js';
 import { walkEntries } from '../walk.js';
-import type { CmdContext, CmdResult, Styler } from '../context.js';
-import { INIT_VERSION, readInitVersion } from '../init-version.js';
 
 export type CheckError = {
   file: string;
@@ -92,14 +91,28 @@ async function tryResolveSourceRef(
   projectRoot: string,
 ): Promise<string | null> {
   if (!isSourcePath(target)) {
-    // Check if it looks like a file path with an unsupported extension
     const hashIdx = target.indexOf('#');
     const filePart = hashIdx === -1 ? target : target.slice(0, hashIdx);
     const ext = extname(filePart);
-    if (ext && hashIdx !== -1) {
+
+    const targetHasHash = hashIdx !== -1;
+
+    // Unsupported extension with # — can't validate symbols
+    if (ext && targetHasHash) {
       const supported = [...SOURCE_EXTENSIONS].sort().join(', ');
-      return `broken link [[${target}]] — unsupported file extension "${ext}". Supported: ${supported}`;
+      return `broken link [[${target}]] — unsupported file extension "${ext}". Symbol references (#) only supported for: ${supported}`;
     }
+
+    // File or folder without # — validate existence
+    if (!targetHasHash) {
+      const absPath = join(projectRoot, filePart);
+      if (existsSync(absPath)) {
+        return null;
+      }
+
+      return `broken link [[${target}]] — file or folder "${filePart}" not found`;
+    }
+
     return `broken link [[${target}]] — no matching section found`;
   }
 

templates/AGENTS.md

@@ -35,7 +35,7 @@ If `lat search` fails because no API key is configured, explain to the user that
 
 - **Section ids**: `lat.md/path/to/file#Heading#SubHeading` — full form uses project-root-relative path (e.g. `lat.md/tests/search#RAG Replay Tests`). Short form uses bare file name when unique (e.g. `search#RAG Replay Tests`, `cli#search#Indexing`).
 - **Wiki links**: `[[target]]` or `[[target|alias]]` — cross-references between sections. Can also reference source code: `[[src/foo.ts#myFunction]]`.
-- **Source code links**: Wiki links in `lat.md/` files can reference functions, classes, constants, and methods in TypeScript/JavaScript/Python/Rust/Go/C files. Use the full path: `[[src/config.ts#getConfigDir]]`, `[[src/server.ts#App#listen]]` (class method), `[[lib/utils.py#parse_args]]`, `[[src/lib.rs#Greeter#greet]]` (Rust impl method), `[[src/app.go#Greeter#Greet]]` (Go method), `[[src/app.h#Greeter]]` (C struct). `lat check` validates these exist.
+- **Source code links**: Wiki links in `lat.md/` files can reference functions, classes, constants, and methods in TypeScript/JavaScript/Python/Rust/Go/C files. Use the full path: `[[src/config.ts#getConfigDir]]`, `[[src/server.ts#App#listen]]` (class method), `[[lib/utils.py#parse_args]]`, `[[src/lib.rs#Greeter#greet]]` (Rust impl method), `[[src/app.go#Greeter#Greet]]` (Go method), `[[src/app.h#Greeter]]` (C struct). Can also link to folders (`[[src/components]]`) or files with any extension (`[[schema.sql]]`) — these are validated to exist. Symbol references (`#`) only work for supported extensions. `lat check` validates these exist.
 - **Code refs**: `// @lat: [[section-id]]` (JS/TS/Rust/Go/C) or `# @lat: [[section-id]]` (Python) — ties source code to concepts
 
 # Test specs

templates/cursor-rules.md

@@ -33,7 +33,7 @@ If `lat_search` fails because `LAT_LLM_KEY` is not set, explain to the user that
 
 - **Section ids**: `lat.md/path/to/file#Heading#SubHeading` — full form uses project-root-relative path (e.g. `lat.md/tests/search#RAG Replay Tests`). Short form uses bare file name when unique (e.g. `search#RAG Replay Tests`, `cli#search#Indexing`).
 - **Wiki links**: `[[target]]` or `[[target|alias]]` — cross-references between sections. Can also reference source code: `[[src/foo.ts#myFunction]]`.
-- **Source code links**: Wiki links in `lat.md/` files can reference functions, classes, constants, and methods in TypeScript/JavaScript/Python/Rust/Go/C files. Use the full path: `[[src/config.ts#getConfigDir]]`, `[[src/server.ts#App#listen]]` (class method), `[[lib/utils.py#parse_args]]`, `[[src/lib.rs#Greeter#greet]]` (Rust impl method), `[[src/app.go#Greeter#Greet]]` (Go method), `[[src/app.h#Greeter]]` (C struct). `lat check` validates these exist.
+- **Source code links**: Wiki links in `lat.md/` files can reference functions, classes, constants, and methods in TypeScript/JavaScript/Python/Rust/Go/C files. Use the full path: `[[src/config.ts#getConfigDir]]`, `[[src/server.ts#App#listen]]` (class method), `[[lib/utils.py#parse_args]]`, `[[src/lib.rs#Greeter#greet]]` (Rust impl method), `[[src/app.go#Greeter#Greet]]` (Go method), `[[src/app.h#Greeter]]` (C struct). Can also link to folders (`[[src/components]]`) or files with any extension (`[[schema.sql]]`) — these are validated to exist. Symbol references (`#`) only work for supported extensions. `lat check` validates these exist.
 - **Code refs**: `// @lat: [[section-id]]` (JS/TS/Rust/Go/C) or `# @lat: [[section-id]]` (Python) — ties source code to concepts
 
 # Test specs

templates/skill/SKILL.md

@@ -85,9 +85,11 @@ Reference functions, classes, constants, and methods in source files:
 [[src/lib.rs#Greeter#greet]]            — Rust impl method
 [[src/app.go#Greeter#Greet]]            — Go method
 [[src/app.h#Greeter]]                   — C struct
+[[src/components]]                      — folder (existence check)
+[[schema.sql]]                          — any file extension (existence check)
 ```
 
-`lat check` validates that all targets exist.
+Symbol references (`#`) only work for supported extensions. File-only and folder links work with any path. `lat check` validates that all targets exist.
 
 ## Code refs
 

tests/cases.test.ts

@@ -658,15 +658,15 @@ describe('error-bare-heading-ref', () => {
     const { errors } = await checkMd(lat);
     const bare = errors.find((e) => e.target === 'Installation');
     expect(bare).toBeDefined();
-    expect(bare!.message).toContain('no matching section found');
+    expect(bare!.message).toContain('not found');
   });
 
   // @lat: [[ref-resolution#Local section syntax in md is error]]
   it('check md rejects [[#Heading]] local section syntax', async () => {
     const { errors } = await checkMd(lat);
     const local = errors.find((e) => e.target === '#Configuration');
     expect(local).toBeDefined();
-    expect(local!.message).toContain('no matching section found');
+    expect(local!.message).toContain('broken link');
   });
 
   // @lat: [[ref-resolution#Nonexistent file ref in md is error]]
@@ -951,13 +951,58 @@ describe('error-source-ref-unsupported-ext', () => {
     expect(errors).toHaveLength(1);
     expect(errors[0].target).toBe('src/app.blah#spam');
     expect(errors[0].message).toContain('unsupported file extension ".blah"');
-    expect(errors[0].message).toContain('Supported:');
+    expect(errors[0].message).toContain('Symbol references (#) only supported for:');
     expect(errors[0].message).toContain('.ts');
     expect(errors[0].message).toContain('.rs');
     expect(errors[0].message).toContain('.go');
   });
 });
 
+describe('source-ref-folder-valid', () => {
+  it('check md accepts wiki link to existing folder', async () => {
+    const { errors } = await checkMd(latDir('source-ref-folder-valid'));
+    expect(errors).toHaveLength(0);
+  });
+});
+
+describe('error-source-ref-bad-folder', () => {
+  it('check md reports broken link for nonexistent folder and folder with symbol ref', async () => {
+    const { errors } = await checkMd(latDir('error-source-ref-bad-folder'));
+    expect(errors).toHaveLength(2);
+    const byTarget = new Map(errors.map((e) => [e.target, e]));
+    expect(byTarget.get('src/nonexistent')!.message).toContain('file or folder "src/nonexistent" not found');
+    expect(byTarget.get('src/components#something')!.message).toContain('no matching section found');
+  });
+});
+
+describe('source-ref-unsupported-ext-valid', () => {
+  it('check md accepts wiki link to existing file with unsupported extension', async () => {
+    const { errors } = await checkMd(latDir('source-ref-unsupported-ext-valid'));
+    expect(errors).toHaveLength(0);
+  });
+});
+
+describe('source-ref-unsupported-ext-root-valid', () => {
+  it('check md accepts wiki link to root-level file with unsupported extension', async () => {
+    const { errors } = await checkMd(latDir('source-ref-unsupported-ext-root-valid'));
+    expect(errors).toHaveLength(0);
+  });
+});
+
+describe('error-source-ref-unsupported-ext-missing', () => {
+  it('check md reports broken link for missing unsupported-ext files and folders', async () => {
+    const { errors } = await checkMd(latDir('error-source-ref-unsupported-ext-missing'));
+    expect(errors).toHaveLength(3);
+    const targets = errors.map((e) => e.target);
+    expect(targets).toContain('nope.sql');
+    expect(targets).toContain('src/missing.sql');
+    expect(targets).toContain('src/missing/');
+    for (const e of errors) {
+      expect(e.message).toContain('not found');
+    }
+  });
+});
+
 // --- source file refs ---
 
 describe('source-file-refs', () => {

tests/cases/error-source-ref-bad-folder/lat.md/docs.md

@@ -0,0 +1,5 @@
+# Docs
+
+Links to a nonexistent folder: [[src/nonexistent]].
+
+Folder with symbol ref: [[src/components#something]].

tests/cases/error-source-ref-unsupported-ext-missing/lat.md/docs.md

@@ -0,0 +1,7 @@
+# Docs
+
+Missing root file: [[nope.sql]].
+
+Missing pathed file: [[src/missing.sql]].
+
+Missing pathed folder: [[src/missing/]].

tests/cases/source-ref-folder-valid/lat.md/docs.md

@@ -0,0 +1,3 @@
+# Docs
+
+Links to a folder: [[src/components]] and [[src/pages/]].

tests/cases/source-ref-unsupported-ext-root-valid/lat.md/docs.md

@@ -0,0 +1,3 @@
+# Docs
+
+Links to a root-level SQL file: [[schema.sql]].

tests/cases/source-ref-unsupported-ext-root-valid/schema.sql

@@ -0,0 +1 @@
+CREATE TABLE users (id INTEGER PRIMARY KEY);

tests/cases/source-ref-unsupported-ext-valid/lat.md/docs.md

@@ -0,0 +1,3 @@
+# Docs
+
+Links to a SQL file: [[src/schema.sql]].

tests/cases/source-ref-unsupported-ext-valid/src/schema.sql

@@ -0,0 +1 @@
+CREATE TABLE users (id INTEGER PRIMARY KEY);