[TIKA-4408] Fix Python env shebang detection

CHANGES.txt

@@ -50,6 +50,9 @@ Release 4.3.0 - ???
 
   EXTRACTION AND FORMATS
 
+   * Detect Python scripts with /usr/bin/env python shebangs as text/x-python
+     instead of application/x-sh (TIKA-4408).
+
    * PPTX slides are extracted in presentation order (p:sldIdLst in presentation.xml)
      instead of relationship-id order, which put rId10 before rId2; embedded-resource
      page numbers follow the same order. Slides that are related but missing from the

tika-core/src/main/resources/org/apache/tika/mime/tika-mimetypes.xml

@@ -8582,7 +8582,8 @@
       <match value="#!/usr/local/bin/python" type="string" offset="0"/>
       <match value="#! /usr/local/bin/python" type="string" offset="0"/>
       <match value="eval &quot;exec /usr/local/bin/python" type="string" offset="0"/>
-      <match value="/bin/env python" type="string" offset="1"/>
+      <match value="#!/usr/bin/env python" type="string" offset="0"/>
+      <match value="#! /usr/bin/env python" type="string" offset="0"/>
     </magic>
     <glob pattern="*.py"/>
     <sub-class-of type="text/plain"/>

tika-core/src/test/java/org/apache/tika/mime/PythonShebangDetectionTest.java

@@ -0,0 +1,75 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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.apache.tika.mime;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.stream.Stream;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import org.apache.tika.Tika;
+
+class PythonShebangDetectionTest {
+
+    private final Tika tika = new Tika();
+
+    static Stream<Arguments> scripts() {
+        return Stream.of(
+                Arguments.of("#!/usr/bin/env python", "print('hello')", "text/x-python"),
+                Arguments.of("#!/usr/bin/env python3", "print('hello')", "text/x-python"),
+                Arguments.of("#! /usr/bin/env python3", "print('hello')", "text/x-python"),
+                Arguments.of("#!/usr/bin/env python3.11", "print('hello')", "text/x-python"),
+                Arguments.of("#!/usr/bin/python3", "print('hello')", "text/x-python"),
+                Arguments.of("#!/bin/python3", "print('hello')", "text/x-python"),
+                Arguments.of("#!/bin/sh", "echo '/bin/env python3'", "application/x-sh"),
+                Arguments.of("#!/usr/bin/env bash", "echo hello", "application/x-sh")
+        );
+    }
+
+    @ParameterizedTest(name = "{0}")
+    @MethodSource("scripts")
+    void testContentOnly(String shebang, String body, String expected) {
+        byte[] content = (shebang + "\n" + body + "\n").getBytes(UTF_8);
+        String actual = tika.detect(content);
+        assertEquals(expected, actual, "Content-only detection: " + shebang);
+    }
+
+    @ParameterizedTest(name = "{0}")
+    @MethodSource("scripts")
+    void testWithPythonFilenameHint(String shebang, String body, String expected) {
+        byte[] content = (shebang + "\n" + body + "\n").getBytes(UTF_8);
+        String actual = tika.detect(content, "script.py");
+        assertEquals(expected, actual, "Detection with script.py hint: " + shebang);
+    }
+
+    @Test
+    void testPythonFilenameOnly() {
+        String actual = tika.detect("script.py");
+        assertEquals("text/x-python", actual);
+    }
+
+    @Test
+    void testPythonShebangMustBeAtStart() {
+        byte[] content = "\n#!/usr/bin/env python3\nprint('hello')\n".getBytes(UTF_8);
+        assertEquals("text/plain", tika.detect(content));
+    }
+}