refactor: track maxDepth via depthLimit Limiter on Context

Replace increaseDepth/decreaseDepth with a shared Limiter that supports
paired use/release, matching templateLimit and outputLengthLimit patterns.

Co-authored-by: Cursor <[email protected]>

src/context/context.ts

@@ -2,7 +2,7 @@ import { Drop } from '../drop/drop'
 import { __assign } from 'tslib'
 import { NormalizedFullOptions, defaultOptions, RenderOptions } from '../liquid-options'
 import { createScope, Scope } from './scope'
-import { hasOwnProperty, isArray, isNil, isUndefined, isString, isFunction, isNumber, toLiquid, InternalUndefinedVariableError, toValueSync, isObject, Limiter, toValue, readArrayElement, assert } from '../util'
+import { hasOwnProperty, isArray, isNil, isUndefined, isString, isFunction, isNumber, toLiquid, InternalUndefinedVariableError, toValueSync, isObject, Limiter, toValue, readArrayElement } from '../util'
 
 type PropertyKey = string | number;
 
@@ -37,8 +37,8 @@ export class Context {
   public ownPropertyOnly: boolean;
   public templateLimit: Limiter;
   public outputLengthLimit: Limiter;
-  public depth: number;
-  public constructor (env: object = {}, opts: NormalizedFullOptions = defaultOptions, renderOptions: RenderOptions = {}, { templateLimit, outputLengthLimit, depth }: { templateLimit?: Limiter, outputLengthLimit?: Limiter, depth?: number } = {}) {
+  public depthLimit: Limiter;
+  public constructor (env: object = {}, opts: NormalizedFullOptions = defaultOptions, renderOptions: RenderOptions = {}, { templateLimit, outputLengthLimit, depthLimit }: { templateLimit?: Limiter, outputLengthLimit?: Limiter, depthLimit?: Limiter } = {}) {
     this.sync = !!renderOptions.sync
     this.opts = opts
     this.globals = renderOptions.globals ?? opts.globals
@@ -47,14 +47,7 @@ export class Context {
     this.ownPropertyOnly = renderOptions.ownPropertyOnly ?? opts.ownPropertyOnly
     this.templateLimit = templateLimit ?? new Limiter('template', renderOptions.templateLimit ?? opts.templateLimit)
     this.outputLengthLimit = outputLengthLimit ?? new Limiter('output length', renderOptions.outputLengthLimit ?? opts.outputLengthLimit)
-    this.depth = depth ?? 0
-  }
-  public increaseDepth () {
-    assert(this.depth < this.opts.maxDepth, 'template depth limit exceeded')
-    this.depth++
-  }
-  public decreaseDepth () {
-    this.depth--
+    this.depthLimit = depthLimit ?? new Limiter('template depth', opts.maxDepth)
   }
   public getRegister<T> (key: string, defaultValue: T = undefined as T): T {
     return (this.registers[key] = this.registers[key] || defaultValue)
@@ -119,7 +112,7 @@ export class Context {
     }, {
       templateLimit: this.templateLimit,
       outputLengthLimit: this.outputLengthLimit,
-      depth: this.depth
+      depthLimit: this.depthLimit
     })
   }
   private findScope (key: string | number) {

src/tags/include.ts

@@ -28,7 +28,7 @@ export default class extends Tag {
     this.hash = new Hash(tokenizer, liquid.options.jekyllInclude || liquid.options.keyValueSeparator)
   }
   * render (ctx: Context, emitter: Emitter): Generator<unknown, void, unknown> {
-    ctx.increaseDepth()
+    ctx.depthLimit.use(1)
     try {
       const { liquid, hash, withVar } = this
       const { renderer } = liquid
@@ -46,7 +46,7 @@ export default class extends Tag {
       ctx.pop()
       ctx.restoreRegister(saved)
     } finally {
-      ctx.decreaseDepth()
+      ctx.depthLimit.release(1)
     }
   }
 

src/tags/layout.ts

@@ -26,7 +26,7 @@ export default class extends Tag {
       yield renderer.renderTemplates(this.templates, ctx, emitter)
       return
     }
-    ctx.increaseDepth()
+    ctx.depthLimit.use(1)
     try {
       const filepath = (yield renderFilePath(this.file, ctx, liquid)) as string
       assert(filepath, () => `illegal file path "${filepath}"`)
@@ -46,7 +46,7 @@ export default class extends Tag {
       yield renderer.renderTemplates(templates, ctx, emitter)
       ctx.pop()
     } finally {
-      ctx.decreaseDepth()
+      ctx.depthLimit.release(1)
     }
   }
 

src/tags/render.ts

@@ -55,7 +55,7 @@ export default class extends Tag {
     this.hash = new Hash(tokenizer, liquid.options.keyValueSeparator)
   }
   * render (ctx: Context, emitter: Emitter): Generator<unknown, void, unknown> {
-    ctx.increaseDepth()
+    ctx.depthLimit.use(1)
     try {
       const { liquid, hash } = this
       const filepath = (yield renderFilePath(this.file, ctx, liquid)) as string
@@ -84,7 +84,7 @@ export default class extends Tag {
         yield liquid.renderer.renderTemplates(templates, childCtx, emitter)
       }
     } finally {
-      ctx.decreaseDepth()
+      ctx.depthLimit.release(1)
     }
   }
 

src/util/limiter.ts

@@ -14,6 +14,11 @@ export class Limiter {
       this.base += +count
     }
   }
+  release (count: number) {
+    if (+count > 0) {
+      this.base -= +count
+    }
+  }
   check (count: number) {
     if (+count > 0) {
       assert(+count <= this.limit, this.message)