Fixes #3410

src/GlobalDependencyMap.js

@@ -373,13 +373,22 @@ class GlobalDependencyMap {
 		}
 
 		// The file that changed is a dependency of the template
+		// comparisonFile is used by fullTemplateInputPath
 		if (this.hasDependency(fullTemplateInputPath, comparisonFile, includeLayouts)) {
 			return true;
 		}
 
 		return false;
 	}
 
+	isFileUsedBy(parent, child, includeLayouts) {
+		if (this.hasDependency(parent, child, includeLayouts)) {
+			// child is used by parent
+			return true;
+		}
+		return false;
+	}
+
 	stringify() {
 		return JSON.stringify(this.map, function replacer(key, value) {
 			// Serialize internal Map objects.

src/Template.js

@@ -889,7 +889,7 @@ class Template extends TemplateContent {
 			let content;
 
 			// Note that behavior.render is overridden when using json or ndjson output
-			if (page.template.behavior.isRenderable()) {
+			if (page.template.isRenderable()) {
 				// this reuses page.templateContent, it doesn’t render it
 				content = await page.template.renderPageEntry(page);
 			}
@@ -918,7 +918,7 @@ class Template extends TemplateContent {
 				continue;
 			}
 
-			if (!page.template.behavior.isRenderable()) {
+			if (!page.template.isRenderable()) {
 				debug("Template not written %o from %o.", page.outputPath, page.template.inputPath);
 				continue;
 			}

src/TemplateWriter.js

@@ -142,7 +142,6 @@ class TemplateWriter {
 
 	_createTemplate(path, to = "fs") {
 		let tmpl = this._templatePathCache.get(path);
-
 		let wasCached = false;
 		if (tmpl) {
 			wasCached = true;
@@ -233,8 +232,13 @@ class TemplateWriter {
 					isFullTemplate: incrementalFileShape === "template",
 				})
 			) {
+				// changed file is used by template
+				// template uses the changed file
 				tmpl.setRenderableOverride(undefined); // unset, probably render
 				secondOrderRelevantLookup[tmpl.inputPath] = true;
+			} else if (this.config.uses.isFileUsedBy(this.incrementalFile, tmpl.inputPath)) {
+				// changed file uses this template
+				tmpl.setRenderableOverride("optional");
 			} else {
 				// For incremental, always disable render on irrelevant templates
 				tmpl.setRenderableOverride(false); // disable render