From 9aff6e82dddf203e3eaa526b123da4211aa7064e Mon Sep 17 00:00:00 2001
From: Rory Abraham <rory@expensify.com>
Date: Mon, 30 Aug 2021 14:10:49 -0700
Subject: [PATCH] Properly JSON-decode outputs

---
 .github/workflows/README.md              | 37 ++++++++++++++++++++++++
 .github/workflows/cherryPick.yml         |  2 +-
 .github/workflows/finishReleaseCycle.yml |  2 +-
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/README.md b/.github/workflows/README.md
index 5e9d5d88f782..be6efb918fb6 100644
--- a/.github/workflows/README.md
+++ b/.github/workflows/README.md
@@ -1,5 +1,42 @@
 # [New Expensify](https://new.expensify.com) GitHub Workflows
 
+## Important tip for creating GitHub Workflows
+All inputs and outputs to GitHub Actions and any data passed between jobs or workflows is JSON-encoded (AKA, strings). Keep this in mind whenever writing GitHub workflows – you may need to JSON-decode variables to access them accurately. Here's an example of a common way to misuse GitHub Actions data:
+
+```yaml
+name: CI
+on: pull_request
+jobs:
+  validate:
+    runs-on: ubuntu-latest
+    steps:
+      - id: myTrueAction
+        uses: Expensify/my-action-outputs-true@main
+
+      - id: myFalseAction
+        uses: Expensify/my-action-outputs-false@main
+
+      # This correctly outputs `true`, but it's a string
+      - run: echo ${{ steps.myTrueAction.outputs.isTrue }}
+
+      # This correctly outputs `false`, but it's a string
+      - run: echo ${{ steps.myFalseAction.outputs.isFalse }}
+
+      # This correctly outputs `true`, and it's a boolean
+      - run: echo ${{ true == true }}
+
+      # This correctly outputs `false`, and it's a boolean.
+      - run: echo ${{ true == false }}
+
+      # Watch out! This seems like it should be true, but it's false!
+      # What we have here is `'false' || true`, and since the first half is a string the expression resolves to 'false'
+      - run: echo ${{ steps.myFalseAction.outputs.isFalse || github.actor == 'roryabraham' }}
+```
+
+We've found that the best way to avoid this pitfall is to always wrap any reference to the output of an action in a call to `fromJSON`. This should force it to resolve to the expected type.
+
+**Note:** Action inputs and outputs aren't the only thing that's JSON-encoded! Any data passed between jobs via a `needs` parameter is also JSON-encoded!
+
 ## Security Rules 🔐
 1. Do **not** use `pull_request_target` trigger unless an external fork needs access to secrets, or a _write_ `GITHUB_TOKEN`.
 1. Do **not ever** write a `pull_request_target` trigger with an explicit PR checkout, e.g. using `actions/checkout@v2`. This is [discussed further here](https://securitylab.github.com/research/github-actions-preventing-pwn-requests)
diff --git a/.github/workflows/cherryPick.yml b/.github/workflows/cherryPick.yml
index 0ab0188ceda0..14f20f707d2b 100644
--- a/.github/workflows/cherryPick.yml
+++ b/.github/workflows/cherryPick.yml
@@ -15,7 +15,7 @@ jobs:
   validateActor:
     runs-on: ubuntu-latest
     outputs:
-      IS_DEPLOYER: ${{ steps.isUserDeployer.outputs.isTeamMember || github.actor == 'OSBotify' }}
+      IS_DEPLOYER: ${{ fromJSON(steps.isUserDeployer.outputs.isTeamMember) || github.actor == 'OSBotify' }}
     steps:
       - id: isUserDeployer
         uses: tspascoal/get-user-teams-membership@baf2e6adf4c3b897bd65a7e3184305c165aec872
diff --git a/.github/workflows/finishReleaseCycle.yml b/.github/workflows/finishReleaseCycle.yml
index d272f1c3de0d..24288e44bb12 100644
--- a/.github/workflows/finishReleaseCycle.yml
+++ b/.github/workflows/finishReleaseCycle.yml
@@ -11,7 +11,7 @@ jobs:
     if: contains(github.event.issue.labels.*.name, 'StagingDeployCash')
 
     outputs:
-      isValid: ${{ steps.validateActor.outputs.isTeamMember && steps.checkDeployBlockers.outputs.HAS_DEPLOY_BLOCKERS == 'false' }}
+      isValid: ${{ fromJSON(steps.validateActor.outputs.isTeamMember) && !fromJSON(steps.checkDeployBlockers.outputs.HAS_DEPLOY_BLOCKERS) }}
 
     steps:
       - name: Validate actor is deployer