From 9970cceaf5c61db2c9201790ec6364065ca9c4ca Mon Sep 17 00:00:00 2001
From: nexdrew <andrewbgoode@gmail.com>
Date: Fri, 1 Sep 2017 13:51:04 -0400
Subject: [PATCH] feat: interpret multiple FROM commands as multi-stage builds

---
 lib/index.js  | 18 +++++++++++++-----
 test/index.js |  6 ------
 2 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/lib/index.js b/lib/index.js
index b40737c..426faf8 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -50,8 +50,10 @@ module.exports.run = function(configPath, content) {
   });
 
   var state = {
-    instructionsProcessed: 0,
-    cmdFound: false,
+    stages: [{
+      instructionsProcessed: 0,
+      cmdFound: false // this doesn't seem to be used anywhere
+    }],
     items: [],
     rules: loadRules(configPath)
   }
@@ -62,11 +64,17 @@ module.exports.run = function(configPath, content) {
 
     // We care about only having 1 cmd instruction
     if (result.command === 'cmd') {
-      state.cmdFound = true;
+      state.stages[state.stages.length - 1].cmdFound = true;
+    } else if (result.command === 'from' && state.stages[state.stages.length - 1].instructionsProcessed !== 0) {
+      // Each FROM command constitutes a new stage in a multistage build
+      state.stages.push({
+        instructionsProcessed: 0,
+        cmdFound: false
+      });
     }
 
     // And we also care about knowing if this is the first command or not
-    state.instructionsProcessed = state.instructionsProcessed + 1;
+    state.stages[state.stages.length - 1].instructionsProcessed++;
   };
 
   return state.items;
@@ -116,7 +124,7 @@ function runLine(state, instructions, idx) {
 
   // check that the first command is a FROM, this might get reported twice, if the FROM command does exist,
   // but is not the time (non blank, non commented) line
-  if ((state.instructionsProcessed === 0 && cmd !== 'from') || (state.instructionsProcessed !== 0 && cmd === 'from')) {
+  if (state.stages[state.stages.length - 1].instructionsProcessed === 0 && cmd !== 'from') {
     items.push(messages.build(state.rules, 'from_first', line));
   }
 
diff --git a/test/index.js b/test/index.js
index a4d4a35..ef7645d 100644
--- a/test/index.js
+++ b/test/index.js
@@ -101,15 +101,9 @@ describe("index", function(){
           { title: 'First Command Must Be FROM',
             rule: 'from_first',
             line: 4 },
-          { title: 'First Command Must Be FROM',
-            rule: 'from_first',
-            line: 5 },
           { title: 'Base Image Missing Tag',
             rule: 'missing_tag',
             line: 5 },
-          { title: 'First Command Must Be FROM',
-            rule: 'from_first',
-            line: 6 },
           { title: 'Base Image Latest Tag',
             rule: 'latest_tag',
             line: 6 },