JLine FFM terminal provider can be disabled at build time using system property

Author: steve-s

sdk/mx.sdk/suite.py

@@ -1205,6 +1205,8 @@ class UniversalDetector {
       # One must pass --enable-native-access=org.graalvm.shadowed.jline, otherwise
       # JLine silently falls back to exec provider on POSIX, and with a warning
       # to "Dumb" provider on Windows
+      # If desired, the FFM terminal on JDK22+ can be disabled at built time using system property:
+      # org.graalvm.shadowed.org.jline.terminal.ffm.disable=true
       "moduleInfo": {
         "name": "org.graalvm.shadowed.jline",
         "requires": [

sdk/src/org.graalvm.shadowed.org.jline.jdk22/src/org/graalvm/shadowed/org/jline/terminal/impl/ffm/FFMTerminalProviderLoader.java

@@ -52,7 +52,16 @@
 import org.graalvm.shadowed.org.jline.terminal.spi.TerminalProvider;
 
 public class FFMTerminalProviderLoader {
+    /**
+     * Build time flag to disable the FFM provider and avoid pulling FFM related code into the
+     * image.
+     */
+    static final boolean DISABLED = Boolean.getBoolean("org.graalvm.shadowed.org.jline.terminal.ffm.disable");
+
     public static TerminalProvider load() {
+        if (DISABLED) {
+            return null;
+        }
         return new org.graalvm.shadowed.org.jline.terminal.impl.ffm.FfmTerminalProvider();
     }
 }
@@ -108,6 +117,9 @@ private static DowncallDesc[] getDowncalls() {
     }
 
     public void duringSetup(DuringSetupAccess access) {
+        if (FFMTerminalProviderLoader.DISABLED) {
+            return;
+        }
         for (DowncallDesc downcall : getDowncalls()) {
             RuntimeForeignAccess.registerForDowncall(downcall.fd(), (Object[]) downcall.options());
         }

sdk/src/org.graalvm.shadowed.org.jline/src/META-INF/native-image/org.graalvm.shadowed/jline/native-image.properties

@@ -2,6 +2,6 @@
 # OSUtils detects current OS capabilities in static ctor
 # FFMTerminalProviderFeature is noop on JDK<=21, on JDK22+ it is overridden using mx overlay mechanism,
 # and it registers FFM downcalls for FFM terminal provider
-Args = --initialize-at-build-time=org.graalvm.shadowed.org.jline \
+Args = --initialize-at-build-time=org.graalvm.shadowed.org.jline,org.graalvm.shadowed.org.jline.terminal.impl.ffm.FFMTerminalProviderLoader \
      --features=org.graalvm.shadowed.org.jline.terminal.impl.ffm.FFMTerminalProviderFeature \
      --initialize-at-run-time=org.graalvm.shadowed.org.jline.utils.AttributedCharSequence,org.graalvm.shadowed.org.jline.utils.OSUtils,org.graalvm.shadowed.org.jline.terminal.impl.ffm \