From 0ddc71359d9fd1f3a56ff9e67956f8d57fdc3a68 Mon Sep 17 00:00:00 2001
From: Alex Russell <slightlyoff@gmail.com>
Date: Sun, 1 Nov 2020 14:39:03 -0800
Subject: [PATCH 1/9] Disgusting hack to prevent NJK from over-compiling

---
 src/Engines/Nunjucks.js | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/src/Engines/Nunjucks.js b/src/Engines/Nunjucks.js
index 34b685e7b..451895ae1 100755
--- a/src/Engines/Nunjucks.js
+++ b/src/Engines/Nunjucks.js
@@ -4,6 +4,34 @@ const TemplatePath = require("../TemplatePath");
 const EleventyErrorUtil = require("../EleventyErrorUtil");
 const EleventyBaseError = require("../EleventyBaseError");
 
+/*
+// HACKITYHACKHACKHACKHACK
+*/
+let pathMap = new Map();
+let tc = NunjucksLib.Template.prototype._compile;
+let getKey = (obj) => {
+  return `${obj.path} :: ${obj.tmplStr.length}`;
+};
+NunjucksLib.Template.prototype._compile = function (...args) {
+  if (!this.tmplProps && pathMap.has(getKey(this))) {
+    // console.log(`### cached ${getKey(this)}`);
+    let pathProps = pathMap.get(getKey(this));
+    this.blocks = pathProps.blocks;
+    this.rootRenderFunc = pathProps.rootRenderFunc;
+    this.compiled = true;
+  } else {
+    tc.call(this, ...args);
+    // console.log(`### caching for ${getKey(this)}`);
+    pathMap.set(getKey(this), {
+      blocks: this.blocks,
+      rootRenderFunc: this.rootRenderFunc,
+    });
+  }
+};
+/*
+// END HACKITYHACKHACKHACKHACK
+*/
+
 class EleventyShortcodeError extends EleventyBaseError {}
 
 class Nunjucks extends TemplateEngine {

From b69f602f6e3bc94ecbf6f7c803706e0ec4b8690c Mon Sep 17 00:00:00 2001
From: Alex Russell <slightlyoff@gmail.com>
Date: Tue, 24 Nov 2020 11:47:26 -0800
Subject: [PATCH 2/9] Correctness fixes on NJK tmpl caching.

---
 src/Engines/Nunjucks.js | 93 +++++++++++++++++++++++++++++++----------
 1 file changed, 70 insertions(+), 23 deletions(-)

diff --git a/src/Engines/Nunjucks.js b/src/Engines/Nunjucks.js
index 451895ae1..c87b98f01 100755
--- a/src/Engines/Nunjucks.js
+++ b/src/Engines/Nunjucks.js
@@ -5,32 +5,76 @@ const EleventyErrorUtil = require("../EleventyErrorUtil");
 const EleventyBaseError = require("../EleventyBaseError");
 
 /*
-// HACKITYHACKHACKHACKHACK
-*/
+ * HACKITYHACKHACKHACKHACK
+ */
+let inc = ((i) => {
+  return () => {
+    return i++;
+  };
+})(0);
 let pathMap = new Map();
-let tc = NunjucksLib.Template.prototype._compile;
-let getKey = (obj) => {
-  return `${obj.path} :: ${obj.tmplStr.length}`;
-};
-NunjucksLib.Template.prototype._compile = function (...args) {
-  if (!this.tmplProps && pathMap.has(getKey(this))) {
-    // console.log(`### cached ${getKey(this)}`);
-    let pathProps = pathMap.get(getKey(this));
-    this.blocks = pathProps.blocks;
-    this.rootRenderFunc = pathProps.rootRenderFunc;
-    this.compiled = true;
-  } else {
-    tc.call(this, ...args);
-    // console.log(`### caching for ${getKey(this)}`);
-    pathMap.set(getKey(this), {
-      blocks: this.blocks,
-      rootRenderFunc: this.rootRenderFunc,
-    });
+
+let clearCache = (reason = "") => {
+  if (pathMap.size > 0) {
+    pathMap.clear();
   }
 };
+
+let clearAndWrap = (name, obj = NunjucksLib.Environment) => {
+  let orig = obj.prototype[name];
+  obj.prototype[name] = function (...args) {
+    clearCache(name);
+    return orig.call(this, ...args);
+  };
+};
+
+clearAndWrap("addExtension");
+clearAndWrap("removeExtension");
+
+(function () {
+  // IFFE to prevent temp var leakage
+  let getKey = (obj) => {
+    let eids = obj.env.extensionsList.reduce((v, c) => {
+      return c.__id ? v + " : " + c.__id : v;
+    }, "");
+    let k =
+      `${obj.path || obj.tmplStr} :: ${obj.tmplStr.length} :: ` +
+      `${obj.env.asyncFilters.length} :: (${eids})`; /* +
+            (
+              (obj.env.extensionsList.length) ? 
+                `${Object.keys(obj.env.extensions).join("|")} :: (${eids})` :
+                ""
+            );
+            */
+    return k;
+  };
+  let tc = NunjucksLib.Template.prototype._compile;
+  NunjucksLib.Template.prototype._compile = function (...args) {
+    // console.log(`NunjucksLib.Template.prototype._compile`);
+    if (!this.compiled && !this.tmplProps && pathMap.has(getKey(this))) {
+      let pathProps = pathMap.get(getKey(this));
+      this.blocks = pathProps.blocks;
+      this.rootRenderFunc = pathProps.rootRenderFunc;
+      this.compiled = true;
+    } else {
+      tc.call(this, ...args);
+      pathMap.set(getKey(this), {
+        blocks: this.blocks,
+        rootRenderFunc: this.rootRenderFunc,
+      });
+    }
+  };
+
+  let ae = NunjucksLib.Environment.prototype.addExtension;
+  NunjucksLib.Environment.prototype.addExtension = function (...args) {
+    let e = args[1];
+    e.__id = inc();
+    return ae.call(this, ...args);
+  };
+})();
 /*
-// END HACKITYHACKHACKHACKHACK
-*/
+ * END HACKITYHACKHACKHACKHACK
+ */
 
 class EleventyShortcodeError extends EleventyBaseError {}
 
@@ -92,6 +136,7 @@ class Nunjucks extends TemplateEngine {
       );
     }
 
+    clearCache("addTag");
     this.njkEnv.addExtension(name, tagObj);
   }
 
@@ -165,7 +210,6 @@ class Nunjucks extends TemplateEngine {
             });
         } else {
           try {
-            // console.log( shortcodeFn.toString() );
             return new NunjucksLib.runtime.SafeString(
               shortcodeFn.call(
                 Nunjucks._normalizeShortcodeContext(context),
@@ -183,6 +227,8 @@ class Nunjucks extends TemplateEngine {
       };
     }
 
+    // Invalidate the caches.
+    clearCache("addShortcode");
     this.njkEnv.addExtension(shortcodeName, new ShortcodeFunction());
   }
 
@@ -253,6 +299,7 @@ class Nunjucks extends TemplateEngine {
       };
     }
 
+    clearCache("addPairedShortcode");
     this.njkEnv.addExtension(shortcodeName, new PairedShortcodeFunction());
   }
 

From bf43bface7c8487783c2d306c4e1be9bb62c2c93 Mon Sep 17 00:00:00 2001
From: Alex Russell <slightlyoff@gmail.com>
Date: Sun, 1 Nov 2020 14:39:03 -0800
Subject: [PATCH 3/9] Disgusting hack to prevent NJK from over-compiling

---
 src/Engines/Nunjucks.js | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/src/Engines/Nunjucks.js b/src/Engines/Nunjucks.js
index 01e349488..94ead1027 100755
--- a/src/Engines/Nunjucks.js
+++ b/src/Engines/Nunjucks.js
@@ -4,6 +4,34 @@ const TemplatePath = require("../TemplatePath");
 const EleventyErrorUtil = require("../EleventyErrorUtil");
 const EleventyBaseError = require("../EleventyBaseError");
 
+/*
+// HACKITYHACKHACKHACKHACK
+*/
+let pathMap = new Map();
+let tc = NunjucksLib.Template.prototype._compile;
+let getKey = (obj) => {
+  return `${obj.path} :: ${obj.tmplStr.length}`;
+};
+NunjucksLib.Template.prototype._compile = function (...args) {
+  if (!this.tmplProps && pathMap.has(getKey(this))) {
+    // console.log(`### cached ${getKey(this)}`);
+    let pathProps = pathMap.get(getKey(this));
+    this.blocks = pathProps.blocks;
+    this.rootRenderFunc = pathProps.rootRenderFunc;
+    this.compiled = true;
+  } else {
+    tc.call(this, ...args);
+    // console.log(`### caching for ${getKey(this)}`);
+    pathMap.set(getKey(this), {
+      blocks: this.blocks,
+      rootRenderFunc: this.rootRenderFunc,
+    });
+  }
+};
+/*
+// END HACKITYHACKHACKHACKHACK
+*/
+
 class EleventyShortcodeError extends EleventyBaseError {}
 
 class Nunjucks extends TemplateEngine {

From e932b41bf050e7db2abe6d7d3f8e794f80b335f9 Mon Sep 17 00:00:00 2001
From: Alex Russell <slightlyoff@gmail.com>
Date: Tue, 24 Nov 2020 11:47:26 -0800
Subject: [PATCH 4/9] Correctness fixes on NJK tmpl caching.

---
 src/Engines/Nunjucks.js | 93 +++++++++++++++++++++++++++++++----------
 1 file changed, 70 insertions(+), 23 deletions(-)

diff --git a/src/Engines/Nunjucks.js b/src/Engines/Nunjucks.js
index 94ead1027..6e46d9dd1 100755
--- a/src/Engines/Nunjucks.js
+++ b/src/Engines/Nunjucks.js
@@ -5,32 +5,76 @@ const EleventyErrorUtil = require("../EleventyErrorUtil");
 const EleventyBaseError = require("../EleventyBaseError");
 
 /*
-// HACKITYHACKHACKHACKHACK
-*/
+ * HACKITYHACKHACKHACKHACK
+ */
+let inc = ((i) => {
+  return () => {
+    return i++;
+  };
+})(0);
 let pathMap = new Map();
-let tc = NunjucksLib.Template.prototype._compile;
-let getKey = (obj) => {
-  return `${obj.path} :: ${obj.tmplStr.length}`;
-};
-NunjucksLib.Template.prototype._compile = function (...args) {
-  if (!this.tmplProps && pathMap.has(getKey(this))) {
-    // console.log(`### cached ${getKey(this)}`);
-    let pathProps = pathMap.get(getKey(this));
-    this.blocks = pathProps.blocks;
-    this.rootRenderFunc = pathProps.rootRenderFunc;
-    this.compiled = true;
-  } else {
-    tc.call(this, ...args);
-    // console.log(`### caching for ${getKey(this)}`);
-    pathMap.set(getKey(this), {
-      blocks: this.blocks,
-      rootRenderFunc: this.rootRenderFunc,
-    });
+
+let clearCache = (reason = "") => {
+  if (pathMap.size > 0) {
+    pathMap.clear();
   }
 };
+
+let clearAndWrap = (name, obj = NunjucksLib.Environment) => {
+  let orig = obj.prototype[name];
+  obj.prototype[name] = function (...args) {
+    clearCache(name);
+    return orig.call(this, ...args);
+  };
+};
+
+clearAndWrap("addExtension");
+clearAndWrap("removeExtension");
+
+(function () {
+  // IFFE to prevent temp var leakage
+  let getKey = (obj) => {
+    let eids = obj.env.extensionsList.reduce((v, c) => {
+      return c.__id ? v + " : " + c.__id : v;
+    }, "");
+    let k =
+      `${obj.path || obj.tmplStr} :: ${obj.tmplStr.length} :: ` +
+      `${obj.env.asyncFilters.length} :: (${eids})`; /* +
+            (
+              (obj.env.extensionsList.length) ? 
+                `${Object.keys(obj.env.extensions).join("|")} :: (${eids})` :
+                ""
+            );
+            */
+    return k;
+  };
+  let tc = NunjucksLib.Template.prototype._compile;
+  NunjucksLib.Template.prototype._compile = function (...args) {
+    // console.log(`NunjucksLib.Template.prototype._compile`);
+    if (!this.compiled && !this.tmplProps && pathMap.has(getKey(this))) {
+      let pathProps = pathMap.get(getKey(this));
+      this.blocks = pathProps.blocks;
+      this.rootRenderFunc = pathProps.rootRenderFunc;
+      this.compiled = true;
+    } else {
+      tc.call(this, ...args);
+      pathMap.set(getKey(this), {
+        blocks: this.blocks,
+        rootRenderFunc: this.rootRenderFunc,
+      });
+    }
+  };
+
+  let ae = NunjucksLib.Environment.prototype.addExtension;
+  NunjucksLib.Environment.prototype.addExtension = function (...args) {
+    let e = args[1];
+    e.__id = inc();
+    return ae.call(this, ...args);
+  };
+})();
 /*
-// END HACKITYHACKHACKHACKHACK
-*/
+ * END HACKITYHACKHACKHACKHACK
+ */
 
 class EleventyShortcodeError extends EleventyBaseError {}
 
@@ -93,6 +137,7 @@ class Nunjucks extends TemplateEngine {
       );
     }
 
+    clearCache("addTag");
     this.njkEnv.addExtension(name, tagObj);
   }
 
@@ -176,7 +221,6 @@ class Nunjucks extends TemplateEngine {
             });
         } else {
           try {
-            // console.log( shortcodeFn.toString() );
             return new NunjucksLib.runtime.SafeString(
               shortcodeFn.call(
                 Nunjucks._normalizeShortcodeContext(context),
@@ -194,6 +238,8 @@ class Nunjucks extends TemplateEngine {
       };
     }
 
+    // Invalidate the caches.
+    clearCache("addShortcode");
     this.njkEnv.addExtension(shortcodeName, new ShortcodeFunction());
   }
 
@@ -264,6 +310,7 @@ class Nunjucks extends TemplateEngine {
       };
     }
 
+    clearCache("addPairedShortcode");
     this.njkEnv.addExtension(shortcodeName, new PairedShortcodeFunction());
   }
 

From 3a005de2124677722643729fb8ea96a44368b5cc Mon Sep 17 00:00:00 2001
From: Alex Russell <slightlyoff@gmail.com>
Date: Tue, 24 Nov 2020 13:35:56 -0800
Subject: [PATCH 5/9] Cleanup variables and scopes per review comments.

---
 src/Engines/Nunjucks.js | 91 +++++++++++++++++------------------------
 1 file changed, 37 insertions(+), 54 deletions(-)

diff --git a/src/Engines/Nunjucks.js b/src/Engines/Nunjucks.js
index 6e46d9dd1..2a71ea46d 100755
--- a/src/Engines/Nunjucks.js
+++ b/src/Engines/Nunjucks.js
@@ -5,76 +5,60 @@ const EleventyErrorUtil = require("../EleventyErrorUtil");
 const EleventyBaseError = require("../EleventyBaseError");
 
 /*
- * HACKITYHACKHACKHACKHACK
+ * This IFFE applies a monkey-patch to Nunjucks internals to cache
+ * compiled templates and re-use them where possible. It's relatively
+ * pessimistic (conservative) about cache clearing to ensure correctness.
  */
-let inc = ((i) => {
-  return () => {
-    return i++;
-  };
-})(0);
-let pathMap = new Map();
-
-let clearCache = (reason = "") => {
-  if (pathMap.size > 0) {
-    pathMap.clear();
-  }
-};
+(function () {
+  let templateCache = new Map();
 
-let clearAndWrap = (name, obj = NunjucksLib.Environment) => {
-  let orig = obj.prototype[name];
-  obj.prototype[name] = function (...args) {
-    clearCache(name);
-    return orig.call(this, ...args);
+  let clearAndWrap = (name, obj = NunjucksLib.Environment) => {
+    let orig = obj.prototype[name];
+    obj.prototype[name] = function (...args) {
+      templateCache.clear();
+      return orig.call(this, ...args);
+    };
   };
-};
 
-clearAndWrap("addExtension");
-clearAndWrap("removeExtension");
+  clearAndWrap("addExtension");
+  clearAndWrap("removeExtension");
 
-(function () {
-  // IFFE to prevent temp var leakage
   let getKey = (obj) => {
-    let eids = obj.env.extensionsList.reduce((v, c) => {
-      return c.__id ? v + " : " + c.__id : v;
-    }, "");
-    let k =
-      `${obj.path || obj.tmplStr} :: ${obj.tmplStr.length} :: ` +
-      `${obj.env.asyncFilters.length} :: (${eids})`; /* +
-            (
-              (obj.env.extensionsList.length) ? 
-                `${Object.keys(obj.env.extensions).join("|")} :: (${eids})` :
-                ""
-            );
-            */
-    return k;
+    return [
+      obj.path || obj.tmplStr,
+      obj.tmplStr.length,
+      obj.env.asyncFilters.length,
+      obj.env.extensionsList
+        .map((e) => {
+          return e.__id || "";
+        })
+        .join(":"),
+    ].join(" :: ");
   };
-  let tc = NunjucksLib.Template.prototype._compile;
+
+  let _compile = NunjucksLib.Template.prototype._compile;
   NunjucksLib.Template.prototype._compile = function (...args) {
-    // console.log(`NunjucksLib.Template.prototype._compile`);
-    if (!this.compiled && !this.tmplProps && pathMap.has(getKey(this))) {
-      let pathProps = pathMap.get(getKey(this));
+    if (!this.compiled && !this.tmplProps && templateCache.has(getKey(this))) {
+      let pathProps = templateCache.get(getKey(this));
       this.blocks = pathProps.blocks;
       this.rootRenderFunc = pathProps.rootRenderFunc;
       this.compiled = true;
     } else {
-      tc.call(this, ...args);
-      pathMap.set(getKey(this), {
+      _compile.call(this, ...args);
+      templateCache.set(getKey(this), {
         blocks: this.blocks,
         rootRenderFunc: this.rootRenderFunc,
       });
     }
   };
 
-  let ae = NunjucksLib.Environment.prototype.addExtension;
-  NunjucksLib.Environment.prototype.addExtension = function (...args) {
-    let e = args[1];
-    e.__id = inc();
-    return ae.call(this, ...args);
+  let extensionIdCounter = 0;
+  let addExtension = NunjucksLib.Environment.prototype.addExtension;
+  NunjucksLib.Environment.prototype.addExtension = function (name, ext) {
+    ext.__id = extensionIdCounter++;
+    return addExtension.call(this, name, ext);
   };
 })();
-/*
- * END HACKITYHACKHACKHACKHACK
- */
 
 class EleventyShortcodeError extends EleventyBaseError {}
 
@@ -137,7 +121,7 @@ class Nunjucks extends TemplateEngine {
       );
     }
 
-    clearCache("addTag");
+    // clearCache();
     this.njkEnv.addExtension(name, tagObj);
   }
 
@@ -238,8 +222,7 @@ class Nunjucks extends TemplateEngine {
       };
     }
 
-    // Invalidate the caches.
-    clearCache("addShortcode");
+    // clearCache();
     this.njkEnv.addExtension(shortcodeName, new ShortcodeFunction());
   }
 
@@ -310,7 +293,7 @@ class Nunjucks extends TemplateEngine {
       };
     }
 
-    clearCache("addPairedShortcode");
+    // clearCache();
     this.njkEnv.addExtension(shortcodeName, new PairedShortcodeFunction());
   }
 

From acad9bdb475c3b9b8ae2c3e8f71a74ce0cc3a6f9 Mon Sep 17 00:00:00 2001
From: Alex Russell <slightlyoff@gmail.com>
Date: Tue, 24 Nov 2020 13:42:14 -0800
Subject: [PATCH 6/9] Further cleanup.

---
 src/Engines/Nunjucks.js | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/Engines/Nunjucks.js b/src/Engines/Nunjucks.js
index 2a71ea46d..86971c734 100755
--- a/src/Engines/Nunjucks.js
+++ b/src/Engines/Nunjucks.js
@@ -37,7 +37,7 @@ const EleventyBaseError = require("../EleventyBaseError");
   };
 
   let _compile = NunjucksLib.Template.prototype._compile;
-  NunjucksLib.Template.prototype._compile = function (...args) {
+  NunjucksLib.Template.prototype._compile = function _wrap_compile(...args) {
     if (!this.compiled && !this.tmplProps && templateCache.has(getKey(this))) {
       let pathProps = templateCache.get(getKey(this));
       this.blocks = pathProps.blocks;
@@ -54,7 +54,10 @@ const EleventyBaseError = require("../EleventyBaseError");
 
   let extensionIdCounter = 0;
   let addExtension = NunjucksLib.Environment.prototype.addExtension;
-  NunjucksLib.Environment.prototype.addExtension = function (name, ext) {
+  NunjucksLib.Environment.prototype.addExtension = function _wrap_addExtension(
+    name,
+    ext
+  ) {
     ext.__id = extensionIdCounter++;
     return addExtension.call(this, name, ext);
   };
@@ -121,7 +124,6 @@ class Nunjucks extends TemplateEngine {
       );
     }
 
-    // clearCache();
     this.njkEnv.addExtension(name, tagObj);
   }
 
@@ -222,7 +224,6 @@ class Nunjucks extends TemplateEngine {
       };
     }
 
-    // clearCache();
     this.njkEnv.addExtension(shortcodeName, new ShortcodeFunction());
   }
 
@@ -293,7 +294,6 @@ class Nunjucks extends TemplateEngine {
       };
     }
 
-    // clearCache();
     this.njkEnv.addExtension(shortcodeName, new PairedShortcodeFunction());
   }
 

From e15ae7914c342a87e0b014c7ac32e4183666aa23 Mon Sep 17 00:00:00 2001
From: Alex Russell <slightlyoff@gmail.com>
Date: Thu, 26 Nov 2020 11:03:44 -0800
Subject: [PATCH 7/9] Less aggressive cache invalidation for a small speedup.

---
 src/Engines/Nunjucks.js | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/src/Engines/Nunjucks.js b/src/Engines/Nunjucks.js
index 86971c734..474f8244e 100755
--- a/src/Engines/Nunjucks.js
+++ b/src/Engines/Nunjucks.js
@@ -12,17 +12,6 @@ const EleventyBaseError = require("../EleventyBaseError");
 (function () {
   let templateCache = new Map();
 
-  let clearAndWrap = (name, obj = NunjucksLib.Environment) => {
-    let orig = obj.prototype[name];
-    obj.prototype[name] = function (...args) {
-      templateCache.clear();
-      return orig.call(this, ...args);
-    };
-  };
-
-  clearAndWrap("addExtension");
-  clearAndWrap("removeExtension");
-
   let getKey = (obj) => {
     return [
       obj.path || obj.tmplStr,
@@ -58,7 +47,9 @@ const EleventyBaseError = require("../EleventyBaseError");
     name,
     ext
   ) {
-    ext.__id = extensionIdCounter++;
+    if (!("__id" in ext)) {
+      ext.__id = extensionIdCounter++;
+    }
     return addExtension.call(this, name, ext);
   };
 })();

From cce873d6cfde4da12392615705c4bde175dd0dc6 Mon Sep 17 00:00:00 2001
From: Alex Russell <slightlyoff@gmail.com>
Date: Thu, 3 Dec 2020 10:35:40 -0800
Subject: [PATCH 8/9] Optmises the hottest loop inside Nunjucks for another
 10-20%.

---
 src/Engines/Nunjucks.js | 47 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 45 insertions(+), 2 deletions(-)

diff --git a/src/Engines/Nunjucks.js b/src/Engines/Nunjucks.js
index 474f8244e..42184f861 100755
--- a/src/Engines/Nunjucks.js
+++ b/src/Engines/Nunjucks.js
@@ -6,8 +6,7 @@ const EleventyBaseError = require("../EleventyBaseError");
 
 /*
  * This IFFE applies a monkey-patch to Nunjucks internals to cache
- * compiled templates and re-use them where possible. It's relatively
- * pessimistic (conservative) about cache clearing to ensure correctness.
+ * compiled templates and re-use them where possible.
  */
 (function () {
   let templateCache = new Map();
@@ -52,6 +51,50 @@ const EleventyBaseError = require("../EleventyBaseError");
     }
     return addExtension.call(this, name, ext);
   };
+
+  // NunjucksLib.runtime.Frame.prototype.set is the hotest in-template method.
+  // We replace it with a version that doesn't allocate a `parts` array on
+  // repeat key use.
+  let partsCache = new Map();
+  let partsFromCache = (name) => {
+    if (partsCache.has(name)) {
+      return partsCache.get(name);
+    }
+
+    let parts = name.split(".");
+    partsCache.set(name, parts);
+    return parts;
+  };
+
+  let frameSet = NunjucksLib.runtime.Frame.prototype.set;
+  NunjucksLib.runtime.Frame.prototype.set = function _replacement_set(
+    name,
+    val,
+    resolveUp
+  ) {
+    let parts = partsFromCache(name);
+    let frame = this;
+    let obj = frame.variables;
+
+    if (resolveUp) {
+      if ((frame = this.resolve(parts[0], true))) {
+        frame.set(name, val);
+        return;
+      }
+    }
+
+    // A slightly faster version of the intermediate object allocation loop
+    let count = parts.length - 1;
+    let i = 0;
+    let id = parts[0];
+    while (i < count) {
+      if (!obj.hasOwnProperty(id)) {
+        obj = obj[id] = {};
+      }
+      id = parts[++i];
+    }
+    obj[id] = val;
+  };
 })();
 
 class EleventyShortcodeError extends EleventyBaseError {}

From 8a47a0752fc91c2d76a7dd451e0da8d7b6e3b9de Mon Sep 17 00:00:00 2001
From: Alex Russell <slightlyoff@gmail.com>
Date: Fri, 4 Dec 2020 15:09:03 -0800
Subject: [PATCH 9/9] Re-enables NJK's internal caching by invalidating caches
 on change.

---
 src/Eleventy.js         |  3 ++-
 src/Engines/Nunjucks.js | 35 ++++++++++++++++++++++++-----------
 src/EventBus.js         | 17 +++++++++++++++++
 src/TemplateContent.js  |  4 ++++
 test/TemplateTest.js    | 28 ++++++++++++++++++----------
 5 files changed, 65 insertions(+), 22 deletions(-)
 create mode 100644 src/EventBus.js

diff --git a/src/Eleventy.js b/src/Eleventy.js
index 0e210d5db..40b3d03a7 100644
--- a/src/Eleventy.js
+++ b/src/Eleventy.js
@@ -18,6 +18,7 @@ const deleteRequireCache = require("./Util/DeleteRequireCache");
 const config = require("./Config");
 const bench = require("./BenchmarkManager");
 const debug = require("debug")("Eleventy");
+const eventBus = require("./EventBus");
 
 /**
  * @module 11ty/eleventy/Eleventy
@@ -449,7 +450,7 @@ Arguments:
    * @param {String} changedFilePath - File that triggered a re-run (added or modified)
    */
   async _addFileToWatchQueue(changedFilePath) {
-    TemplateContent.deleteCached(changedFilePath);
+    eventBus.emit("resourceModified", changedFilePath);
     this.watchManager.addToPendingQueue(changedFilePath);
   }
 
diff --git a/src/Engines/Nunjucks.js b/src/Engines/Nunjucks.js
index 42184f861..dfcc9614f 100755
--- a/src/Engines/Nunjucks.js
+++ b/src/Engines/Nunjucks.js
@@ -3,9 +3,10 @@ const TemplateEngine = require("./TemplateEngine");
 const TemplatePath = require("../TemplatePath");
 const EleventyErrorUtil = require("../EleventyErrorUtil");
 const EleventyBaseError = require("../EleventyBaseError");
+const eventBus = require("../EventBus");
 
 /*
- * This IFFE applies a monkey-patch to Nunjucks internals to cache
+ * The IFFE below apply a monkey-patch to Nunjucks internals to cache
  * compiled templates and re-use them where possible.
  */
 (function () {
@@ -24,6 +25,17 @@ const EleventyBaseError = require("../EleventyBaseError");
     ].join(" :: ");
   };
 
+  let evictByPath = (path) => {
+    let keys = templateCache.keys();
+    // Likely to be slow; do we care?
+    for (let k of keys) {
+      if (k.indexOf(path) >= 0) {
+        templateCache.delete(k);
+      }
+    }
+  };
+  eventBus.on("resourceModified", evictByPath);
+
   let _compile = NunjucksLib.Template.prototype._compile;
   NunjucksLib.Template.prototype._compile = function _wrap_compile(...args) {
     if (!this.compiled && !this.tmplProps && templateCache.has(getKey(this))) {
@@ -109,16 +121,17 @@ class Nunjucks extends TemplateEngine {
   }
 
   setLibrary(env) {
-    this.njkEnv =
-      env ||
-      new NunjucksLib.Environment(
-        new NunjucksLib.FileSystemLoader(
-          [super.getIncludesDir(), TemplatePath.getWorkingDir()],
-          {
-            noCache: true,
-          }
-        )
-      );
+    let fsLoader = new NunjucksLib.FileSystemLoader([
+      super.getIncludesDir(),
+      TemplatePath.getWorkingDir(),
+    ]);
+    this.njkEnv = env || new NunjucksLib.Environment(fsLoader);
+    // Correct, but overbroad. Better would be to evict more granularly, but
+    // resolution from paths isn't straightforward.
+    eventBus.on("resourceModified", (path) => {
+      this.njkEnv.invalidateCache();
+    });
+
     this.setEngineLib(this.njkEnv);
 
     this.addFilters(this.config.nunjucksFilters);
diff --git a/src/EventBus.js b/src/EventBus.js
new file mode 100644
index 000000000..682b87c3f
--- /dev/null
+++ b/src/EventBus.js
@@ -0,0 +1,17 @@
+const EventEmitter = require("./Util/AsyncEventEmitter");
+const debug = require("debug")("Eleventy:EventBus");
+
+/**
+ * @module 11ty/eleventy/EventBus
+ */
+
+debug("Setting up global EventBus.");
+/**
+ * Provides a global event bus that modules deep down in the stack can
+ * subscribe to from a global singleton for decoupled pub/sub.
+ * @type * {module:11ty/eleventy/Util/AsyncEventEmitter~AsyncEventEmitter}
+ */
+let bus = new EventEmitter();
+bus.setMaxListeners(100);
+
+module.exports = bus;
diff --git a/src/TemplateContent.js b/src/TemplateContent.js
index 7fefe5810..7853e77aa 100644
--- a/src/TemplateContent.js
+++ b/src/TemplateContent.js
@@ -14,6 +14,7 @@ const config = require("./Config");
 const debug = require("debug")("Eleventy:TemplateContent");
 const debugDev = require("debug")("Dev:Eleventy:TemplateContent");
 const bench = require("./BenchmarkManager").get("Aggregate");
+const eventBus = require("./EventBus");
 
 class TemplateContentFrontMatterError extends EleventyBaseError {}
 class TemplateContentCompileError extends EleventyBaseError {}
@@ -277,5 +278,8 @@ class TemplateContent {
 
 TemplateContent._inputCache = new Map();
 TemplateContent._compileEngineCache = new Map();
+eventBus.on("resourceModified", (path) => {
+  TemplateContent.deleteCached(path);
+});
 
 module.exports = TemplateContent;
diff --git a/test/TemplateTest.js b/test/TemplateTest.js
index cd016bcd3..95cfd99f5 100644
--- a/test/TemplateTest.js
+++ b/test/TemplateTest.js
@@ -2049,11 +2049,9 @@ test("Engine Singletons", async (t) => {
 });
 
 test("Make sure layout cache takes new changes during watch (nunjucks)", async (t) => {
-  await fsp.writeFile(
-    "./test/stubs-layout-cache/_includes/include-script-1.js",
-    `alert("hi");`,
-    { encoding: "utf8" }
-  );
+  let filePath = "./test/stubs-layout-cache/_includes/include-script-1.js";
+
+  await fsp.writeFile(filePath, `alert("hi");`, { encoding: "utf8" });
 
   let tmpl = getNewTemplate(
     "./test/stubs-layout-cache/test.njk",
@@ -2065,13 +2063,23 @@ test("Make sure layout cache takes new changes during watch (nunjucks)", async (
 
   t.is((await tmpl.render(data)).trim(), '<script>alert("hi");</script>');
 
-  await fsp.writeFile(
-    "./test/stubs-layout-cache/_includes/include-script-1.js",
-    `alert("bye");`,
-    { encoding: "utf8" }
-  );
+  let eventBus = require("../src/EventBus");
+  let chokidar = require("chokidar");
+  let watcher = chokidar.watch(filePath, { interval: 10, persistent: true });
+  watcher.on("change", (path, stats) => {
+    eventBus.emit("resourceModified", path);
+  });
+
+  await fsp.writeFile(filePath, `alert("bye");`, { encoding: "utf8" });
+
+  // Give Chokidar time to see the change;
+  await new Promise((res, rej) => {
+    setTimeout(res, 200);
+  });
 
   t.is((await tmpl.render(data)).trim(), '<script>alert("bye");</script>');
+
+  await watcher.close();
 });
 
 test("Make sure layout cache takes new changes during watch (liquid)", async (t) => {