From 71a9eee041935c78a267f96a76ee9121d15b06a1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Eric=20Meadows-J=C3=B6nsson?=
 <eric.meadows.jonsson@gmail.com>
Date: Sun, 17 Nov 2019 23:40:55 +0100
Subject: [PATCH] Support elixir branches

---
 .github/workflows/test.yml |  3 +++
 src/install-elixir         |  6 +++---
 src/installer.js           |  3 ++-
 src/setup-elixir.js        | 34 ++++++++++++++++++++++------------
 4 files changed, 30 insertions(+), 16 deletions(-)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 2bb4c25..f09163b 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -18,6 +18,9 @@ jobs:
           # Semver ranges
           - otp-version: 21.x
             elixir-version: <1.9.1
+          # Branches
+          - otp-version: 22.0
+            elixir-version: master
     steps:
       - uses: actions/checkout@v1.0.0
       - name: Use actions/setup-elixir
diff --git a/src/install-elixir b/src/install-elixir
index f767922..8fc616c 100755
--- a/src/install-elixir
+++ b/src/install-elixir
@@ -2,7 +2,7 @@
 
 set -eo pipefail
 
-wget -q https://repo.hex.pm/builds/elixir/v${1}-otp-${2}.zip
-unzip -d .setup-elixir/elixir v${1}-otp-${2}.zip
-rm v${1}-otp-${2}.zip
+wget -q https://repo.hex.pm/builds/elixir/${1}${2}.zip
+unzip -d .setup-elixir/elixir ${1}${2}.zip
+rm ${1}${2}.zip
 echo "::add-path::$(pwd)/.setup-elixir/elixir/bin"
diff --git a/src/installer.js b/src/installer.js
index 9b2bc51..7a55dbf 100644
--- a/src/installer.js
+++ b/src/installer.js
@@ -12,7 +12,8 @@ module.exports = {installElixir, installOTP}
  */
 async function installElixir(version, otpMajor) {
   if (process.platform === 'linux') {
-    await exec(path.join(__dirname, 'install-elixir'), [version, otpMajor])
+    const otpString = otpMajor ? `-otp-${otpMajor}` : ''
+    await exec(path.join(__dirname, 'install-elixir'), [version, otpString])
   }
 }
 
diff --git a/src/setup-elixir.js b/src/setup-elixir.js
index ba85c13..24e0b68 100644
--- a/src/setup-elixir.js
+++ b/src/setup-elixir.js
@@ -14,8 +14,8 @@ async function main() {
 
   const otpSpec = core.getInput('otp-version', {required: true})
   const elixirSpec = core.getInput('elixir-version', {required: true})
-  const otpVersion = getVersionFromSpec(otpSpec, await getOtpVersions())
-  const [elixirVersion, otpMajor] = getElixirVersion(elixirSpec, await getElixirVersions(), otpVersion)
+  const otpVersion = await getOtpVersion(otpSpec)
+  const [elixirVersion, otpMajor] = await getElixirVersion(elixirSpec, otpVersion)
 
   let installHex = core.getInput('install-hex')
   installHex = installHex == null ? true : installHex
@@ -42,23 +42,33 @@ function checkPlatform() {
     )
 }
 
-function getElixirVersion(spec, versions, otpVersion) {
-  const version = getVersionFromSpec(spec, Array.from(versions.keys()))
+async function getOtpVersion(spec) {
+  return getVersionFromSpec(spec, await getOtpVersions()) || spec
+}
+
+async function getElixirVersion(spec, otpVersion) {
+  const versions = await getElixirVersions()
+  const semverRegex = /^v(\d+\.\d+\.\d+)/
+
+  const semverVersions =
+    Array.from(versions.keys())
+      .filter(str => str.match(semverRegex))
+      .map(str => str.match(semverRegex)[1])
+
+  const version = getVersionFromSpec(spec, semverVersions)
+  const gitRef = version ? `v${version}` : spec
   const [otpMajor] = otpVersion.match(/^\d+/)
 
-  if (versions.get(version).includes(otpMajor)) {
-    return [version, otpMajor]
+  if (versions.get(gitRef).includes(otpMajor)) {
+    return [gitRef, otpMajor]
   } else {
-    throw new Error(
-      `Elixir ${version} and OTP ${otpVersion} are incompatible`
-    )
+    return [gitRef, null]
   }
 }
 
 function getVersionFromSpec(spec, versions) {
   const range = semver.validRange(spec)
-  const version = semver.maxSatisfying(versions, range)
-  return version || spec
+  return semver.maxSatisfying(versions, range)
 }
 
 async function getOtpVersions() {
@@ -75,7 +85,7 @@ async function getElixirVersions() {
   const map = new Map()
 
   result.trim().split('\n').forEach(line => {
-    const match = line.match(/^v(\d+\.\d+\.\d+)-otp-(\d+)/)
+    const match = line.match(/^(v\d+\.\d+\.\d+)-otp-(\d+)/) || line.match(/^([^-]+)-otp-(\d+)/)
 
     if (match) {
       const [_, version, otp] = match