v1 of style Autodetect

rewrite-python/src/main/java/org/openrewrite/python/style/Autodetect.java

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+/*
+ * Copyright 2025 the original author or authors.
+ * <p>
+ * Licensed under the Moderne Source Available License (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://docs.moderne.io/licensing/moderne-source-available-license
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.python.style;
+
+import org.openrewrite.SourceFile;
+import org.openrewrite.Tree;
+import org.openrewrite.java.tree.J;
+import org.openrewrite.java.tree.Statement;
+import org.openrewrite.python.PythonIsoVisitor;
+import org.openrewrite.python.tree.Py;
+import org.openrewrite.style.NamedStyles;
+import org.openrewrite.style.Style;
+
+import java.util.*;
+
+public class Autodetect extends NamedStyles implements PythonStyle {
+    public Autodetect(UUID id, Collection<Style> styles) {
+        super(id,
+                "org.openrewrite.python.Autodetect",
+                "Auto-detected",
+                "Automatically detect styles from a repository's existing code.",
+                Collections.emptySet(),
+                styles);
+    }
+
+    public static Detector detector() {
+        return new Detector();
+    }
+
+    public static class Detector {
+        private final IndentStatistics indentStatistics = new IndentStatistics();
+        private final FindIndentVisitor indentVisitor = new FindIndentVisitor();
+
+        public void sample(SourceFile python) {
+            if (python instanceof Py.CompilationUnit) {
+                indentVisitor.visitNonNull(python, indentStatistics);
+            }
+        }
+
+        public Autodetect build() {
+            return new Autodetect(
+                    Tree.randomId(),
+                    Collections.singletonList(indentStatistics.getTabsAndIndentsStyle())
+            );
+        }
+    }
+
+    private static class IndentStatistics {
+        private final Map<Integer, Integer> countsByIndentSize = new HashMap<>();
+
+        private<T> T keyWithHighestCount(Map<T, Integer> counts) {
+            int max = Collections.max(counts.values());
+            return counts.entrySet()
+                    .stream()
+                    .filter(entry -> entry.getValue() == max)
+                    .findFirst().get().getKey();
+        }
+
+        public TabsAndIndentsStyle getTabsAndIndentsStyle() {
+            int mostPopularIndent = keyWithHighestCount(countsByIndentSize);
+            return new TabsAndIndentsStyle(false, 2, mostPopularIndent, 4, false);
+        }
+    }
+
+    private static class FindIndentVisitor extends PythonIsoVisitor<IndentStatistics> {
+        private int currentBlockIndent = 0;
+
+        private int countSpaces(String s) {
+            int withoutSpaces = s.replaceAll(" ", "").length();
+            return s.length() - withoutSpaces;
+        }
+
+        @Override
+        public J.Block visitBlock(J.Block block, IndentStatistics indentStatistics) {
+            int blockIndentBeforeThisBlock = currentBlockIndent;
+            int currentBlockIndentSize = 0;
+
+            if (!block.getStatements().isEmpty()) {
+                this.currentBlockIndent = countSpaces(block.getStatements().get(0).getPrefix().getWhitespace());
+                currentBlockIndentSize = this.currentBlockIndent - blockIndentBeforeThisBlock;
+            }
+
+            for (Statement s : block.getStatements()) {
+                int spaceCount = countSpaces(s.getPrefix().getWhitespace());
+                int relativeIndentSize = spaceCount - this.currentBlockIndent;
+                int classifyAsIndentSize = relativeIndentSize + currentBlockIndentSize;
+                indentStatistics.countsByIndentSize.put(classifyAsIndentSize, indentStatistics.countsByIndentSize.getOrDefault(classifyAsIndentSize, 0) + 1);
+            }
+            J.Block ret = super.visitBlock(block, indentStatistics);
+            this.currentBlockIndent = blockIndentBeforeThisBlock;
+            return ret;
+        }
+    }
+}

rewrite-python/src/test/java/org/openrewrite/python/style/AutodetectTest.java

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+/*
+ * Copyright 2025 the original author or authors.
+ * <p>
+ * Licensed under the Moderne Source Available License (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://docs.moderne.io/licensing/moderne-source-available-license
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.python.style;
+
+import org.junit.jupiter.api.Test;
+import org.openrewrite.test.RecipeSpec;
+import org.openrewrite.test.RewriteTest;
+
+import java.util.function.Consumer;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.openrewrite.python.Assertions.python;
+
+public class AutodetectTest implements RewriteTest {
+
+    @Test
+    void autodetectSpaces2() {
+        rewriteRun(
+          hasIndentation(2),
+          python("""
+          if 1 > 0:
+           print("This one-space indent will be effectively ignored")
+
+          for i in range(1, 24):
+            print(i)
+            for j in range(1, i):
+              x = j * j
+              print(i, j)
+          """)
+        );
+    }
+
+    @Test
+    void autodetectSpaces4() {
+        rewriteRun(
+          hasIndentation(4),
+          python("""
+          if 1 > 0:
+           print("This one-space indent will be effectively ignored")
+
+          for i in range(1, 24):
+              print(i)
+              for j in range(1, i):
+                  x = j * j
+                  print(i, j)
+          """)
+        );
+    }
+
+    private static Consumer<RecipeSpec> hasIndentation(int indentSize) {
+        return spec -> spec.beforeRecipe(sources -> {
+            Autodetect.Detector detector = Autodetect.detector();
+            sources.forEach(detector::sample);
+
+            TabsAndIndentsStyle tabsAndIndents = (TabsAndIndentsStyle) detector.build().getStyles().stream()
+              .filter(TabsAndIndentsStyle.class::isInstance)
+              .findAny().orElseThrow();
+            assertThat(tabsAndIndents.getIndentSize()).isEqualTo(indentSize);
+        });
+    }
+}