feat(eslint): add no-pointless-reassignments rule

- Create custom ESLint rule to detect pointless variable reassignments
- A pointless reassignment is when a const/let is assigned to a single identifier
  with no transformation (e.g., `const x = y;` where y is already the target)
- Exempt underscore-prefixed variables (exhaustiveness check patterns)
- Fix all 16 violations throughout the codebase by:
  - Removing unnecessary schema aliases in CLI commands
  - Refactoring json-to-md parentDir initialization to use ternary
  - Converting remove-node's let-based accumulator to immutable updates object
  - Removing unused type alias export (TraceNode const)

All 458 tests pass. Linting now 100% clean with new rule enabled.

Author: Mearman

eslint.config.ts

@@ -75,10 +75,42 @@ const indexReExportsOnly: Rule.RuleModule = {
 	},
 };
 
+const noPointlessReassignments: Rule.RuleModule = {
+	meta: {
+		type: "problem",
+		messages: {
+			pointlessReassignment:
+				"Pointless reassignment. {{ name }} is just an alias for {{ value }}. Use the original directly instead.",
+		},
+	},
+	create(context) {
+		return {
+			VariableDeclarator(node) {
+				if (node.id.type !== "Identifier" || node.init?.type !== "Identifier") {
+					return;
+				}
+				// Skip intentional patterns (underscore prefix = exhaustiveness checks, etc.)
+				if (node.id.name.startsWith("_")) {
+					return;
+				}
+				context.report({
+					node,
+					messageId: "pointlessReassignment",
+					data: {
+						name: node.id.name,
+						value: node.init.name,
+					},
+				});
+			},
+		};
+	},
+};
+
 const barrelPlugin = {
 	rules: {
 		"no-re-exports": noReExports,
 		"index-re-exports-only": indexReExportsOnly,
+		"no-pointless-reassignments": noPointlessReassignments,
 	},
 };
 
@@ -135,6 +167,7 @@ export default defineConfig(
 			],
 			"barrel/no-re-exports": "error",
 			"barrel/index-re-exports-only": "error",
+			"barrel/no-pointless-reassignments": "error",
 			"eslint-comments/no-use": "error",
 		},
 	},

src/cli/commands/check.ts

@@ -2,13 +2,11 @@ import type { CommandDef } from "../define-command.js";
 import { checkOp } from "../../operations/index.js";
 import { noArgs, readOpts, loadDoc } from "../shared.js";
 
-const optsSchema = readOpts;
-
-export const checkCommand: CommandDef<typeof noArgs, typeof optsSchema> = {
+export const checkCommand: CommandDef<typeof noArgs, typeof readOpts> = {
 	name: "check",
 	description: checkOp.def.description,
 	apiLink: checkOp.def.name,
-	opts: optsSchema,
+	opts: readOpts,
 	action(_args, opts) {
 		const { doc } = loadDoc(opts.path);
 		const result = checkOp({ doc });

src/cli/commands/json2md.ts

@@ -43,10 +43,8 @@ export const json2mdCommand: CommandDef = {
 	action(args: unknown, opts: unknown) {
 		if (!isArgs(args)) throw new Error("Invalid args");
 		if (!isOpts(opts)) throw new Error("Invalid opts");
-		const typedArgs = args;
-		const typedOpts = opts;
-		const inputPath = resolve(typedArgs.input);
-		const outputPath = resolve(typedArgs.output);
+		const inputPath = resolve(args.input);
+		const outputPath = resolve(args.output);
 
 		const raw: unknown = JSON.parse(readFileSync(inputPath, "utf8"));
 
@@ -62,7 +60,7 @@ export const json2mdCommand: CommandDef = {
 		}
 
 		const form =
-			typedOpts.singleFile || outputPath.endsWith(".md")
+			opts.singleFile || outputPath.endsWith(".md")
 				? "single-file"
 				: "multi-doc";
 

src/cli/commands/md2json.ts

@@ -28,9 +28,8 @@ export const md2jsonCommand: CommandDef = {
 	opts: z.object({}).strict(),
 	action(args: unknown) {
 		if (!isArgs(args)) throw new Error("Invalid args");
-		const typedArgs = args;
-		const inputPath = resolve(typedArgs.input);
-		const outputPath = resolve(typedArgs.output);
+		const inputPath = resolve(args.input);
+		const outputPath = resolve(args.output);
 
 		const doc = markdownToJson(inputPath);
 		writeFileSync(outputPath, canonicalise(doc, { indent: "\t" }) + "\n");

src/cli/commands/query.ts

@@ -96,7 +96,6 @@ const nodesOpts = readOpts.extend({
 const nodeArgs = z.object({
 	id: z.string().describe("node ID to retrieve"),
 });
-const nodeOpts = readOpts;
 
 const relsOpts = readOpts.extend({
 	from: z.string().optional().describe("filter relationships by source node"),
@@ -107,7 +106,6 @@ const relsOpts = readOpts.extend({
 const traceArgs = z.object({
 	id: z.string().describe("node ID to start trace from"),
 });
-const traceOpts = readOpts;
 
 const timelineOpts = readOpts.extend({
 	node: z.string().optional().describe("filter events to a specific node"),
@@ -116,7 +114,6 @@ const timelineOpts = readOpts.extend({
 const stateAtArgs = z.object({
 	time: z.string().describe("ISO timestamp to query"),
 });
-const stateAtOpts = readOpts;
 
 // ---------------------------------------------------------------------------
 // Subcommands
@@ -145,10 +142,10 @@ const nodeSubcommand: CommandDef = {
 	description: queryNodeOp.def.description,
 	apiLink: queryNodeOp.def.name,
 	args: nodeArgs,
-	opts: nodeOpts,
+	opts: readOpts,
 	action(rawArgs: unknown, rawOpts: unknown) {
 		const args = nodeArgs.parse(rawArgs);
-		const opts = nodeOpts.parse(rawOpts);
+		const opts = readOpts.parse(rawOpts);
 		const { doc } = loadDoc(opts.path);
 		const result = queryNodeOp({ doc, id: args.id });
 		if (!result) {
@@ -205,10 +202,10 @@ const traceSubcommand: CommandDef = {
 	description: traceFromNodeOp.def.description,
 	apiLink: traceFromNodeOp.def.name,
 	args: traceArgs,
-	opts: traceOpts,
+	opts: readOpts,
 	action(rawArgs: unknown, rawOpts: unknown) {
 		const args = traceArgs.parse(rawArgs);
-		const opts = traceOpts.parse(rawOpts);
+		const opts = readOpts.parse(rawOpts);
 		const { doc } = loadDoc(opts.path);
 		const trace = traceFromNodeOp({ doc, startId: args.id });
 		if (opts.json) {
@@ -251,10 +248,10 @@ const stateAtSubcommand: CommandDef = {
 	description: stateAtOp.def.description,
 	apiLink: stateAtOp.def.name,
 	args: stateAtArgs,
-	opts: stateAtOpts,
+	opts: readOpts,
 	action(rawArgs: unknown, rawOpts: unknown) {
 		const args = stateAtArgs.parse(rawArgs);
-		const opts = stateAtOpts.parse(rawOpts);
+		const opts = readOpts.parse(rawOpts);
 		const { doc } = loadDoc(opts.path);
 		const result = stateAtOp({ doc, timestamp: args.time });
 		if (opts.json) {

src/cli/commands/rename.ts

@@ -8,33 +8,32 @@ const argsSchema = z.object({
 	newId: z.string().describe("New node ID"),
 });
 
-const optsSchema = mutationOpts;
+export const renameCommand: CommandDef<typeof argsSchema, typeof mutationOpts> =
+	{
+		name: "rename",
+		description: renameOp.def.description,
+		apiLink: renameOp.def.name,
+		args: argsSchema,
+		opts: mutationOpts,
+		action(args, opts) {
+			try {
+				const loaded = loadDoc(opts.path);
+				const { doc } = loaded;
+				const updated = renameOp({ doc, oldId: args.oldId, newId: args.newId });
+				persistDoc(updated, loaded, opts);
 
-export const renameCommand: CommandDef<typeof argsSchema, typeof optsSchema> = {
-	name: "rename",
-	description: renameOp.def.description,
-	apiLink: renameOp.def.name,
-	args: argsSchema,
-	opts: optsSchema,
-	action(args, opts) {
-		try {
-			const loaded = loadDoc(opts.path);
-			const { doc } = loaded;
-			const updated = renameOp({ doc, oldId: args.oldId, newId: args.newId });
-			persistDoc(updated, loaded, opts);
-
-			if (opts.json) {
-				console.log(
-					JSON.stringify({ oldId: args.oldId, newId: args.newId }, null, 2),
-				);
-			} else {
-				console.log(
-					`${opts.dryRun ? "[dry-run] Would rename" : "Renamed"} ${args.oldId} → ${args.newId}`,
-				);
+				if (opts.json) {
+					console.log(
+						JSON.stringify({ oldId: args.oldId, newId: args.newId }, null, 2),
+					);
+				} else {
+					console.log(
+						`${opts.dryRun ? "[dry-run] Would rename" : "Renamed"} ${args.oldId} → ${args.newId}`,
+					);
+				}
+			} catch (err: unknown) {
+				console.error(err instanceof Error ? err.message : String(err));
+				process.exit(1);
 			}
-		} catch (err: unknown) {
-			console.error(err instanceof Error ? err.message : String(err));
-			process.exit(1);
-		}
-	},
-};
+		},
+	};

src/cli/commands/search.ts

@@ -8,14 +8,12 @@ const argsSchema = z.object({
 	term: z.string().describe("Search term"),
 });
 
-const optsSchema = readOpts;
-
-export const searchCommand: CommandDef<typeof argsSchema, typeof optsSchema> = {
+export const searchCommand: CommandDef<typeof argsSchema, typeof readOpts> = {
 	name: "search",
 	description: searchOp.def.description,
 	apiLink: searchOp.def.name,
 	args: argsSchema,
-	opts: optsSchema,
+	opts: readOpts,
 	action(args, opts) {
 		const { doc } = loadDoc(opts.path);
 		const matches = searchOp({ doc, term: args.term });

src/cli/commands/stats.ts

@@ -3,13 +3,11 @@ import type { CommandDef } from "../define-command.js";
 import { statsOp } from "../../operations/index.js";
 import { noArgs, readOpts, loadDoc } from "../shared.js";
 
-const optsSchema = readOpts;
-
-export const statsCommand: CommandDef<typeof noArgs, typeof optsSchema> = {
+export const statsCommand: CommandDef<typeof noArgs, typeof readOpts> = {
 	name: "stats",
 	description: statsOp.def.description,
 	apiLink: statsOp.def.name,
-	opts: optsSchema,
+	opts: readOpts,
 	action(_args, opts) {
 		const { doc } = loadDoc(opts.path);
 		const s = statsOp({ doc });

src/cli/commands/update.ts

@@ -54,14 +54,12 @@ const addRelArgs = z.object({
 	type: RelationshipType.describe("relationship type"),
 	to: z.string().describe("target node ID"),
 });
-const addRelOpts = mutationOpts;
 
 const removeRelArgs = z.object({
 	from: z.string().describe("source node ID"),
 	type: RelationshipType.describe("relationship type"),
 	to: z.string().describe("target node ID"),
 });
-const removeRelOpts = mutationOpts;
 
 const metaOpts = mutationOpts.extend({
 	fields: z
@@ -141,10 +139,10 @@ const addRelSubcommand: CommandDef = {
 	description: addRelationshipOp.def.description,
 	apiLink: addRelationshipOp.def.name,
 	args: addRelArgs,
-	opts: addRelOpts,
+	opts: mutationOpts,
 	action(rawArgs: unknown, rawOpts: unknown) {
 		const args = addRelArgs.parse(rawArgs);
-		const opts = addRelOpts.parse(rawOpts);
+		const opts = mutationOpts.parse(rawOpts);
 		const loaded = loadDoc(opts.path);
 		const { doc } = loaded;
 
@@ -173,10 +171,10 @@ const removeRelSubcommand: CommandDef = {
 	description: removeRelationshipOp.def.description,
 	apiLink: removeRelationshipOp.def.name,
 	args: removeRelArgs,
-	opts: removeRelOpts,
+	opts: mutationOpts,
 	action(rawArgs: unknown, rawOpts: unknown) {
 		const args = removeRelArgs.parse(rawArgs);
-		const opts = removeRelOpts.parse(rawOpts);
+		const opts = mutationOpts.parse(rawOpts);
 		const loaded = loadDoc(opts.path);
 		const { doc } = loaded;
 

src/cli/commands/validate.ts

@@ -3,13 +3,11 @@ import type { CommandDef } from "../define-command.js";
 import { validateOp } from "../../operations/index.js";
 import { noArgs, readOpts, loadDoc } from "../shared.js";
 
-const optsSchema = readOpts;
-
-export const validateCommand: CommandDef<typeof noArgs, typeof optsSchema> = {
+export const validateCommand: CommandDef<typeof noArgs, typeof readOpts> = {
 	name: "validate",
 	description: validateOp.def.description,
 	apiLink: validateOp.def.name,
-	opts: optsSchema,
+	opts: readOpts,
 	action(_args, opts) {
 		const { doc } = loadDoc(opts.path);
 		const result = validateOp({ doc });