fix: address harttle#404 to allow argument reassignment

src/builtin/tags/assign.ts

@@ -10,6 +10,7 @@ export default {
     this.value = tokenizer.remaining()
   },
   render: function * (ctx: Context) {
-    ctx.bottom()[this.key] = yield this.liquid._evalValue(this.value, ctx)
+    const firstPageLevelScope = ctx.getFirstPageLevelScope()
+    firstPageLevelScope[this.key] = yield this.liquid._evalValue(this.value, ctx)
   }
 } as TagImplOptions

src/builtin/tags/include.ts

@@ -34,7 +34,7 @@ export default {
     const scope = yield hash.render(ctx)
     if (withVar) scope[filepath] = evalToken(withVar, ctx)
     const templates = yield liquid._parsePartialFile(filepath, ctx.sync, this['currentFile'])
-    ctx.push(scope)
+    ctx.push({ ...scope, isPageLevel: true })
     yield renderer.renderTemplates(templates, ctx, emitter)
     ctx.pop()
     ctx.restoreRegister(saved)

src/builtin/tags/render.ts

@@ -56,7 +56,7 @@ export default {
       const { value, alias } = this['with']
       scope[alias || filepath] = evalToken(value, ctx)
     }
-    childCtx.push(scope)
+    childCtx.push({ ...scope, isPageLevel: true })
 
     if (this['for']) {
       const { value, alias } = this['for']

src/context/context.ts

@@ -57,6 +57,11 @@ export class Context {
   public bottom () {
     return this.scopes[0]
   }
+  /** Returns the first scope that's considered to be a page-level scope, if one exists. Otherwise, defaults to `bottom`. */
+  public getFirstPageLevelScope () {
+    const firstPageLevelScope = this.scopes.find((scope: Scope) => scope.isPageLevel)
+    return firstPageLevelScope || this.bottom()
+  }
   private findScope (key: string) {
     for (let i = this.scopes.length - 1; i >= 0; i--) {
       const candidate = this.scopes[i]

src/context/scope.ts

@@ -5,4 +5,8 @@ export interface PlainObject {
   toLiquid?: () => any;
 }
 
-export type Scope = PlainObject | Drop
+export type Scope = (PlainObject | Drop) & {
+  /** Whether this is a page-level scope (e.g., corresponding to include/render/layout).
+   * Transient scopes (like those created by a for loop) are not considered to be page-level scopes. */
+  isPageLevel?: boolean;
+}

test/integration/builtin/tags/assign.ts

@@ -69,6 +69,11 @@ describe('tags/assign', function () {
     const html = await liquid.parseAndRender(src)
     return expect(html).to.equal('-6')
   })
+  it('should allow reassignment', async function () {
+    const src = '{% assign var = 1 %}{% assign var = 2 %}{{ var }}'
+    const html = await liquid.parseAndRender(src)
+    return expect(html).to.equal('2')
+  })
   describe('scope', function () {
     it('should read from parent scope', async function () {
       const src = '{%for a in (1..2)%}{{num}}{%endfor%}'

test/integration/builtin/tags/include.ts

@@ -194,6 +194,16 @@ describe('tags/include', function () {
       const html = await staticLiquid.renderFile('parent.html')
       return expect(html).to.equal('Xchild with redY')
     })
+
+    it('should allow argument reassignment', async function () {
+      mock({
+        '/parent.html': '{% include child.html, color: "red" %}',
+        '/child.html': '{% assign color = "green" %}{{ color }}'
+      })
+      const staticLiquid = new Liquid({ dynamicPartials: false, root: '/' })
+      const html = await staticLiquid.renderFile('parent.html')
+      return expect(html).to.equal('green')
+    })
   })
   describe('sync support', function () {
     it('should support quoted string', function () {