From 192e6f6c3d771b0e6f03816c4f13202cf5b27b4e Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>
Date: Thu, 25 May 2023 14:50:17 +0100
Subject: [PATCH] Fix PR lookup for `fetchdep.sh` (#10990)

Context: `fetchdep.sh` attempts to check out a github repository based on the
details in a pull request. To do this, it needs to know how to find the pull
request. So, the github workflows attempt to set environment variables to tell
it. Unfortunately, they currently disagree about what the names of the
environment variables should be.

This appears to have been introduced by #8498.

To simplify matters, we may as well have the script use `${GITHUB_REPOSITORY}`
directly, and remove te unused `REPOSITORY` env var from the workflows.
---
 .github/workflows/element-web.yaml     |  5 +++--
 .github/workflows/static_analysis.yaml |  5 +++--
 .github/workflows/tests.yml            |  5 +++--
 scripts/fetchdep.sh                    | 11 +++++++++--
 4 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/.github/workflows/element-web.yaml b/.github/workflows/element-web.yaml
index 022c293abe..e08803c216 100644
--- a/.github/workflows/element-web.yaml
+++ b/.github/workflows/element-web.yaml
@@ -15,10 +15,11 @@ on:
 concurrency:
     group: ${{ github.workflow }}-${{ github.ref }}-${{ github.event_name }}
     cancel-in-progress: true
+
 env:
-    # These must be set for fetchdep.sh to get the right branch
-    REPOSITORY: ${{ github.repository }}
+    # fetchdep.sh needs to know our PR number
     PR_NUMBER: ${{ github.event.pull_request.number }}
+
 jobs:
     build:
         name: "Build Element-Web"
diff --git a/.github/workflows/static_analysis.yaml b/.github/workflows/static_analysis.yaml
index b95fc3b1c8..c4bf0ef3be 100644
--- a/.github/workflows/static_analysis.yaml
+++ b/.github/workflows/static_analysis.yaml
@@ -10,10 +10,11 @@ on:
 concurrency:
     group: ${{ github.workflow }}-${{ github.ref }}-${{ github.event_name }}
     cancel-in-progress: true
+
 env:
-    # These must be set for fetchdep.sh to get the right branch
-    REPOSITORY: ${{ github.repository }}
+    # fetchdep.sh needs to know our PR number
     PR_NUMBER: ${{ github.event.pull_request.number }}
+
 jobs:
     ts_lint:
         name: "Typescript Syntax Check"
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index bdc1badd6a..ad8fdab8c7 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -20,11 +20,12 @@ on:
 concurrency:
     group: ${{ github.workflow }}-${{ github.ref }}-${{ github.event_name }}
     cancel-in-progress: true
+
 env:
     ENABLE_COVERAGE: ${{ github.event_name != 'merge_group' && inputs.disable_coverage != 'true' }}
-    # These must be set for fetchdep.sh to get the right branch
-    REPOSITORY: ${{ github.repository }}
+    # fetchdep.sh needs to know our PR number
     PR_NUMBER: ${{ github.event.pull_request.number }}
+
 jobs:
     jest:
         name: Jest
diff --git a/scripts/fetchdep.sh b/scripts/fetchdep.sh
index 81f0784ff9..3a8b9be4dd 100755
--- a/scripts/fetchdep.sh
+++ b/scripts/fetchdep.sh
@@ -10,8 +10,15 @@ defbranch="$3"
 
 rm -r "$defrepo" || true
 
-PR_ORG=${PR_ORG:-"matrix-org"}
-PR_REPO=${PR_REPO:-"matrix-react-sdk"}
+# figure out where to look for pull requests:
+#   - We may have been told an explicit repo via the PR_ORG/PR_REPO/PR_NUMBER env vars
+#   - otherwise, check the $GITHUB_ env vars which are set by Github Actions
+#   - failing that, fall back to the matrix-org/matrix-react-sdk repo.
+#
+# in ether case, the PR_NUMBER variable must be set explicitly.
+default_org_repo=${GITHUB_REPOSITORY:-"matrix-org/matrix-react-sdk"}
+PR_ORG=${PR_ORG:-${default_org_repo%%/*}}
+PR_REPO=${PR_REPO:-${default_org_repo##*/}}
 
 # A function that clones a branch of a repo based on the org, repo and branch
 clone() {