From 51143a88833e28f974d558c44b1ab215b7ff2798 Mon Sep 17 00:00:00 2001
From: CR Drost <C.R.Drost@gmail.com>
Date: Tue, 21 Nov 2017 16:45:52 -0600
Subject: [PATCH 1/2] Fixes #149 by adding a 30-pass limit to recursion and
 stopping immediately on loops.

---
 src/compiler-host.js | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/compiler-host.js b/src/compiler-host.js
index d602004..345ec43 100644
--- a/src/compiler-host.js
+++ b/src/compiler-host.js
@@ -323,7 +323,7 @@ export default class CompilerHost {
    *
    * @private
    */
-  async compileUncached(filePath, hashInfo, compiler) {
+  async compileUncached(filePath, hashInfo, compiler, history=[]) {
     let inputMimeType = mimeTypes.lookup(filePath);
 
     if (hashInfo.isFileBinary) {
@@ -336,6 +336,7 @@ export default class CompilerHost {
 
     let ctx = {};
     let code = hashInfo.sourceCode || await pfs.readFile(filePath, 'utf8');
+    history.push(code);
 
     if (!(await compiler.shouldCompileFile(code, ctx))) {
       d(`Compiler returned false for shouldCompileFile: ${filePath}`);
@@ -359,6 +360,12 @@ export default class CompilerHost {
     if ((finalForms[result.mimeType] && !shouldInlineHtmlify) || isPassthrough) {
       // Got something we can use in-browser, let's return it
       return Object.assign(result, {dependentFiles});
+    } else if (history.indexOf(result.code) !== -1) {
+      d(`Compiler loop, I have seen this source before: ${JSON.stringify(result)}`);
+      return Object.assign(result, {dependentFiles});
+    } else if (history.length > 30) {
+      d(`Runaway compilation: ${JSON.stringify({history: history, result: result})}`);
+      throw new Error(`Compiling ${filePath} resulted in a recursive recompilation more than 30 levels deep; assuming broken...`);
     } else {
       d(`Recursively compiling result of ${filePath} with non-final MIME type ${result.mimeType}, input was ${inputMimeType}`);
 
@@ -373,7 +380,7 @@ export default class CompilerHost {
 
       return await this.compileUncached(
         `${filePath}.${mimeTypes.extension(result.mimeType || 'txt')}`,
-        hashInfo, compiler);
+        hashInfo, compiler, history);
     }
   }
 

From 407ff4ba2875396bdafcee88a9bf7d900cfaa085 Mon Sep 17 00:00:00 2001
From: CR Drost <C.R.Drost@gmail.com>
Date: Tue, 21 Nov 2017 17:13:35 -0600
Subject: [PATCH 2/2] Change [] to set, log less stuff.

---
 src/compiler-host.js | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/src/compiler-host.js b/src/compiler-host.js
index 345ec43..7ba61e2 100644
--- a/src/compiler-host.js
+++ b/src/compiler-host.js
@@ -323,7 +323,7 @@ export default class CompilerHost {
    *
    * @private
    */
-  async compileUncached(filePath, hashInfo, compiler, history=[]) {
+  async compileUncached(filePath, hashInfo, compiler, history=new Set()) {
     let inputMimeType = mimeTypes.lookup(filePath);
 
     if (hashInfo.isFileBinary) {
@@ -336,7 +336,7 @@ export default class CompilerHost {
 
     let ctx = {};
     let code = hashInfo.sourceCode || await pfs.readFile(filePath, 'utf8');
-    history.push(code);
+    history.add(code);
 
     if (!(await compiler.shouldCompileFile(code, ctx))) {
       d(`Compiler returned false for shouldCompileFile: ${filePath}`);
@@ -360,12 +360,11 @@ export default class CompilerHost {
     if ((finalForms[result.mimeType] && !shouldInlineHtmlify) || isPassthrough) {
       // Got something we can use in-browser, let's return it
       return Object.assign(result, {dependentFiles});
-    } else if (history.indexOf(result.code) !== -1) {
-      d(`Compiler loop, I have seen this source before: ${JSON.stringify(result)}`);
+    } else if (history.has(result.code)) {
+      d(`Compiler loop on ${filePath} after ${history.size - 1} prior candidates: assuming OK.`);
       return Object.assign(result, {dependentFiles});
-    } else if (history.length > 30) {
-      d(`Runaway compilation: ${JSON.stringify({history: history, result: result})}`);
-      throw new Error(`Compiling ${filePath} resulted in a recursive recompilation more than 30 levels deep; assuming broken...`);
+    } else if (history.size > 30) {
+      throw new Error(`Compiling ${filePath} resulted in a recursive recompilation more than 30 levels deep: assuming broken.`);
     } else {
       d(`Recursively compiling result of ${filePath} with non-final MIME type ${result.mimeType}, input was ${inputMimeType}`);