Switch to a build variant config instead of magic env vars (#2498)

.github/workflows/build_linux.yaml

@@ -145,8 +145,9 @@ jobs:
             - name: Build App
               run: yarn build --publish never -l ${{ steps.config.outputs.build-args }}
               env:
+                  VARIANT_PATH: variant.json
                   # Only set for Nightly builds
-                  ED_NIGHTLY: ${{ inputs.version }}
+                  VERSION: ${{ inputs.version }}
 
             - name: Check native libraries
               run: |

.github/workflows/build_macos.yaml

@@ -96,8 +96,9 @@ jobs:
                   APPLE_APP_SPECIFIC_PASSWORD: ${{ secrets.APPLE_ID_PASSWORD }}
                   CSC_KEY_PASSWORD: ${{ secrets.APPLE_CSC_KEY_PASSWORD }}
                   CSC_LINK: ${{ secrets.APPLE_CSC_LINK }}
+                  VARIANT_PATH: variant.json
                   # Only set for Nightly builds
-                  ED_NIGHTLY: ${{ inputs.version }}
+                  VERSION: ${{ inputs.version }}
 
             - name: Check app was signed & notarised successfully
               if: inputs.sign != ''
@@ -113,6 +114,7 @@ jobs:
                   yarn build:universal --publish never
               env:
                   CSC_IDENTITY_AUTO_DISCOVERY: false
+                  VARIANT_PATH: variant.json
 
             - name: Generate releases.json
               if: inputs.base-url

.github/workflows/build_prepare.yaml

@@ -85,6 +85,11 @@ jobs:
               if: steps.branch-matching.outcome == 'failure' || steps.branch-matching.outcome == 'skipped'
               run: yarn run fetch --noverify -d ${{ inputs.config }} ${{ inputs.version }}
 
+            - name: Copy variant config
+              run: cp "$CONFIG_DIR/build.json" variant.json
+              env:
+                  CONFIG_DIR: ${{ inputs.config }}
+
             # We split this out to save the build_* scripts having to do it to make use of `hashFiles` in the cache action
             - name: Generate cache hash files
               run: |
@@ -170,3 +175,4 @@ jobs:
                       electronVersion
                       hakHash
                       changelog.Debian
+                      variant.json

.github/workflows/build_windows.yaml

@@ -193,8 +193,14 @@ jobs:
             - name: Build App
               run: yarn build --publish never -w ${{ steps.config.outputs.build-args }}
               env:
+                  VARIANT_PATH: variant.json
                   # Only set for Nightly builds
-                  ED_NIGHTLY: ${{ inputs.version }}
+                  # The windows packager relies on parsing this as semver, so we have to make it look like one.
+                  # This will give our update packages really stupid names, but we probably can't change that either
+                  # because squirrel windows parses them for the version too. We don't really care: nobody sees them.
+                  # We just give the installer a static name, so you'll just see this in the 'about' dialog.
+                  # Turns out if you use 0.0.0 here it makes Squirrel windows crash, so we use 0.0.1.
+                  VERSION: ${{ inputs.version && format('0.0.1-nightly.{0}', inputs.version) || '' }}
 
             - name: Trust eSigner sandbox cert
               if: inputs.sign == ''