Test stdlib-bootstrapped TASTy-MiMa in CI

.github/workflows/ci.yaml

@@ -255,6 +255,11 @@ jobs:
         run: |
           ./project/scripts/sbt ";scala3-interfaces/mimaReportBinaryIssues ;scala3-library-bootstrapped/mimaReportBinaryIssues ;scala3-library-bootstrappedJS/mimaReportBinaryIssues; tasty-core-bootstrapped/mimaReportBinaryIssues; stdlib-bootstrapped/mimaReportBinaryIssues"
 
+      - name: TASTy MiMa
+        run: |
+          # This script cleans the compiler and recompiles it from scratch (keep as last run)
+          ./project/scripts/stdlib-bootstrapped-tasty-mima.sh
+
   community_build_a:
     runs-on: [self-hosted, Linux]
     container:

project/scripts/stdlib-bootstrapped-tasty-mima.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+set -eux
+
+source $(dirname $0)/cmdTestsCommon.inc.sh
+
+TASTY_FROMAT_FILE="tasty/src/dotty/tools/tasty/TastyFormat.scala"
+MINOR_TASTY_VERSION_SUPPORTED_BY_TASTY_MIMA=3
+MINOR_TASTY_VERSION=$(grep -oE 'val MinorVersion: Int = ([0-9]+)' $TASTY_FROMAT_FILE | grep -oE '[0-9]+')
+EXPERIMENTAL_TASTY_VERSION=$(grep -oE 'val ExperimentalVersion: Int = ([0-9]+)' $TASTY_FROMAT_FILE | grep -oE '[0-9]+')
+
+setTastyVersion() {
+  sed -i -E -e "s/val MinorVersion: Int = [0-9]+/val MinorVersion: Int = $1/" -e "s/val ExperimentalVersion: Int = [0-9]+/val ExperimentalVersion: Int = $2/" $TASTY_FROMAT_FILE
+}
+
+setTastyVersion $MINOR_TASTY_VERSION_SUPPORTED_BY_TASTY_MIMA 0
+
+# Run stdlib-bootstrapped/tastyMiMaReportIssues using a custom TASTy version.
+# We clean before to make sure all sources are recompiled using the new TASTY version.
+# We clean after to make sure no other test will use the TASTy generated with this version.
+"$SBT" "clean; stdlib-bootstrapped/clean; reload; stdlib-bootstrapped/tastyMiMaReportIssues; clean; stdlib-bootstrapped/clean"
+
+setTastyVersion $MINOR_TASTY_VERSION $EXPERIMENTAL_TASTY_VERSION