Detect unbalanced Graphics state in the simulator (#5058)

.github/workflows/input-validation.yml

@@ -82,24 +82,6 @@ jobs:
         id: setup_hash
         run: echo "hash=$(shasum -a 256 scripts/setup-workspace.sh | awk '{print $1}')" >> "$GITHUB_OUTPUT"
 
-      - name: Compute CN1 source hash
-        id: src_hash
-        run: |
-          set -euo pipefail
-          SRC_HASH=$(find CodenameOne/src Ports/iOSPort vm/JavaAPI vm/ByteCodeTranslator Themes native-themes \
-              maven/codenameone-maven-plugin/src/main \
-              -type f \( -name '*.java' -o -name '*.m' -o -name '*.h' -o -name '*.xml' -o -name '*.properties' -o -name '*.css' \) 2>/dev/null \
-              | sort | xargs shasum -a 256 | shasum -a 256 | awk '{print $1}')
-          POM_HASH=$(find . -name 'pom.xml' -not -path './scripts/*' 2>/dev/null \
-              | sort | xargs shasum -a 256 | shasum -a 256 | awk '{print $1}')
-          SCRIPT_HASH=$(shasum -a 256 \
-              scripts/setup-workspace.sh \
-              scripts/build-ios-port.sh \
-              scripts/build-native-themes.sh \
-              .github/workflows/_build-ios-port.yml \
-              | shasum -a 256 | awk '{print $1}')
-          echo "hash=${SRC_HASH:0:16}-${POM_HASH:0:16}-${SCRIPT_HASH:0:16}" >> "$GITHUB_OUTPUT"
-
       - name: Set TMPDIR
         run: echo "TMPDIR=${{ runner.temp }}" >> $GITHUB_ENV
 
@@ -128,13 +110,18 @@ jobs:
             cn1-binaries-${{ runner.os }}-
 
       - name: Restore built CN1 + iOS port artifacts
+        # Reuse the exact cache key the build-port job saved against. Locally
+        # recomputing the hash here has drifted out of sync with
+        # _build-ios-port.yml before (e.g. svg-transcoder/src/main added on
+        # one side only), causing a permanent cache miss for any PR that
+        # touches a file matching this workflow's paths filter.
         uses: actions/cache/restore@v4
         with:
           path: |
             ~/.m2/repository/com/codenameone
             Themes
             Ports/iOSPort/nativeSources
-          key: cn1-built-${{ runner.os }}-${{ steps.src_hash.outputs.hash }}
+          key: ${{ needs.build-port.outputs.cn1_built_cache_key }}
           fail-on-cache-miss: true
 
       - name: Install XcodeGen

CodenameOne/src/com/codename1/impl/CodenameOneImplementation.java

@@ -1963,6 +1963,18 @@ public void popClip(Object graphics) {
 
     }
 
+    /// Marks the start of a user-overrideable paint scope (e.g. `Component.paint`,
+    /// `Component.paintBackground`, `Painter.paint`, glass pane). Ports may use this
+    /// to snapshot graphics state and validate that the scope leaves it unchanged.
+    /// Default is a no-op so device ports pay zero cost.
+    public void beginPaintScope(Object graphics, Object owner) {
+    }
+
+    /// Marks the end of a paint scope opened by `#beginPaintScope`. Must be paired
+    /// with a `beginPaintScope` call on the same graphics with the same owner.
+    public void endPaintScope(Object graphics, Object owner) {
+    }
+
     /// Draws a line between the 2 X/Y coordinates
     ///
     /// #### Parameters

CodenameOne/src/com/codename1/ui/Component.java

@@ -3001,13 +3001,23 @@ void internalPaintImpl(Graphics g, boolean paintIntersects) {
             int scrollX = getScrollX();
             int scrollY = getScrollY();
             g.translate(-scrollX, -scrollY);
-            paint(g);
+            Display.impl.beginPaintScope(g.getGraphics(), this);
+            try {
+                paint(g);
+            } finally {
+                Display.impl.endPaintScope(g.getGraphics(), this);
+            }
             g.translate(scrollX, scrollY);
             if (isScrollVisible) {
                 paintScrollbars(g);
             }
         } else {
-            paint(g);
+            Display.impl.beginPaintScope(g.getGraphics(), this);
+            try {
+                paint(g);
+            } finally {
+                Display.impl.endPaintScope(g.getGraphics(), this);
+            }
         }
         if (isBorderPainted()) {
             paintBorder(g);
@@ -3395,9 +3405,19 @@ private void drawPaintersImpl(Graphics g, Component par, Component c,
                 rect.getSize().setWidth(par.getWidth());
                 rect.getSize().setHeight(par.getHeight());
             }
-            p.paint(g, rect);
+            Display.impl.beginPaintScope(g.getGraphics(), p);
+            try {
+                p.paint(g, rect);
+            } finally {
+                Display.impl.endPaintScope(g.getGraphics(), p);
+            }
+        }
+        Display.impl.beginPaintScope(g.getGraphics(), par);
+        try {
+            par.paintBackground(g);
+        } finally {
+            Display.impl.endPaintScope(g.getGraphics(), par);
         }
-        par.paintBackground(g);
         ((Container) par).paintIntersecting(g, c, x, y, w, h, false, 0);
         g.translate(-transX, -transY);
     }
@@ -3469,9 +3489,20 @@ private void paintBackgroundImpl(Graphics g) {
             }
         }
         if (getStyle().getBgPainter() != null) {
-            getStyle().getBgPainter().paint(g, bounds);
+            Painter bp = getStyle().getBgPainter();
+            Display.impl.beginPaintScope(g.getGraphics(), bp);
+            try {
+                bp.paint(g, bounds);
+            } finally {
+                Display.impl.endPaintScope(g.getGraphics(), bp);
+            }
+        }
+        Display.impl.beginPaintScope(g.getGraphics(), this);
+        try {
+            paintBackground(g);
+        } finally {
+            Display.impl.endPaintScope(g.getGraphics(), this);
         }
-        paintBackground(g);
         paintRippleEffect(g);
     }
 
@@ -5086,7 +5117,12 @@ protected Image getDragImage() {
 
         g.translate(-getX(), -getY());
         paintComponentBackground(g);
-        paint(g);
+        Display.impl.beginPaintScope(g.getGraphics(), this);
+        try {
+            paint(g);
+        } finally {
+            Display.impl.endPaintScope(g.getGraphics(), this);
+        }
         if (isBorderPainted()) {
             paintBorder(g);
         }
@@ -5132,7 +5168,12 @@ public Image toImage() {
 
         g.translate(-getX(), -getY());
         paintComponentBackground(g);
-        paint(g);
+        Display.impl.beginPaintScope(g.getGraphics(), this);
+        try {
+            paint(g);
+        } finally {
+            Display.impl.endPaintScope(g.getGraphics(), this);
+        }
         if (isBorderPainted()) {
             paintBorder(g);
         }

CodenameOne/src/com/codename1/ui/Form.java

@@ -1123,10 +1123,20 @@ void paintGlassImpl(Graphics g) {
             int tx = g.getTranslateX();
             int ty = g.getTranslateY();
             g.translate(-tx, -ty);
-            glassPane.paint(g, getBounds());
+            Display.impl.beginPaintScope(g.getGraphics(), glassPane);
+            try {
+                glassPane.paint(g, getBounds());
+            } finally {
+                Display.impl.endPaintScope(g.getGraphics(), glassPane);
+            }
             g.translate(tx, ty);
         }
-        paintGlass(g);
+        Display.impl.beginPaintScope(g.getGraphics(), this);
+        try {
+            paintGlass(g);
+        } finally {
+            Display.impl.endPaintScope(g.getGraphics(), this);
+        }
         if (dragged != null && dragged.isDragAndDropInitialized()) {
             int[] c = g.getClip();
             g.setClip(0, 0, getWidth(), getHeight());