From 56d891583ed5a3ce4c7bd53e507ed97339854a06 Mon Sep 17 00:00:00 2001
From: Daniel Wirtz <dcode@dcode.io>
Date: Wed, 21 Mar 2018 13:26:11 +0100
Subject: [PATCH] Add a build check for PRs (#51)

This now checks that distribution files are unmodified and fails otherwise. Also checks if the author is present in the NOTICE file and prints the result, but as email addresses may vary, does not hard-fail.
---
 .gitattributes      |  1 +
 .travis.yml         | 10 ++++++++++
 scripts/check-pr.sh | 29 +++++++++++++++++++++++++++++
 src/types.ts        |  2 +-
 4 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100755 scripts/check-pr.sh

diff --git a/.gitattributes b/.gitattributes
index a17611cd..4583b202 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,3 +1,4 @@
 bin/asc text eol=lf
 dist/asc.js -diff
 dist/assemblyscript.js -diff
+scripts/check-pr.sh eol=lf
diff --git a/.travis.yml b/.travis.yml
index d3cf2688..6b5f9f69 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,7 +1,17 @@
 language: node_js
+notifications:
+  email: false
+stages:
+  - name: check-pr
+    if: type = pull_request
 jobs:
   include:
 
+  - stage: check-pr
+    node_js: lts/*
+    script: ./scripts/check-pr.sh
+    env: Checks contributing guidelines before testing pull requests
+
   - stage: lint
     node_js: node
     script: npm run lint
diff --git a/scripts/check-pr.sh b/scripts/check-pr.sh
new file mode 100755
index 00000000..1657439c
--- /dev/null
+++ b/scripts/check-pr.sh
@@ -0,0 +1,29 @@
+# Distribution files should not be modified
+STATUS=0
+if git --no-pager diff --name-only FETCH_HEAD $(git merge-base FETCH_HEAD $TRAVIS_BRANCH) | grep -q "^dist/"; then
+  STATUS=1 &&
+  printf "\n" &&
+  printf "The pull request includes changes to distribution files, but it shouldn't.\n" &&
+  printf "Please see https://github.com/AssemblyScript/assemblyscript/blob/master/CONTRIBUTING.md\n";
+else
+  printf "\n" &&
+  printf "GOOD: The pull request does not include changes to distribution files.\n";
+fi
+
+# Authors should have added themself to the NOTICE file
+AUTHOR=$(git log -1 --format="%aE")
+if [ -z "$AUTHOR" ]; then
+  printf "\n" &&
+  printf "Skipping NOTICE check: Commit does not include an email address.\n";
+else
+  if grep -q "$AUTHOR" NOTICE; then
+    printf "\n" &&
+    printf "GOOD: Author is present in the NOTICE file.\n";
+  else
+    printf "\n" &&
+    printf "Author does not appear to be listed in the NOTICE file, yet.\n" &&
+    printf "Please see https://github.com/AssemblyScript/assemblyscript/blob/master/CONTRIBUTING.md\n";
+  fi
+fi
+
+exit $STATUS
diff --git a/src/types.ts b/src/types.ts
index 94b93b4d..c410e126 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -541,7 +541,7 @@ export class Signature {
     // check return type
     var thisReturnType = this.returnType;
     var targetReturnType = target.returnType;
-    return thisReturnType == targetReturnType || this.returnType.isAssignableTo(target.returnType);
+    return thisReturnType == targetReturnType || thisReturnType.isAssignableTo(targetReturnType);
   }
 
   /** Converts this signature to a function type string. */