feat: add early module import validation for Java

codeflash/code_utils/config_java_validation.py

@@ -0,0 +1,121 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+
+def validate_java_module_resolution(source_file: Path, project_root: Path, module_root: Path) -> tuple[bool, str]:
+    """Validate that a Java source file can be compiled and tested within the given module structure.
+
+    Checks:
+    - Source file exists
+    - Source file is within project root
+    - A build config (pom.xml, build.gradle, build.gradle.kts) exists in project root
+    - Source file is within module root
+    - Package declaration matches directory structure
+
+    Returns:
+        (True, "") if valid, (False, error_message) if invalid.
+
+    """
+    source_file = source_file.resolve()
+    project_root = project_root.resolve()
+    module_root = module_root.resolve()
+
+    if not source_file.exists():
+        return False, f"Source file does not exist: {source_file}"
+
+    try:
+        source_file.relative_to(project_root)
+    except ValueError:
+        return False, f"Source file {source_file} is outside the project root {project_root}"
+
+    has_build_config = (
+        (project_root / "pom.xml").exists()
+        or (project_root / "build.gradle").exists()
+        or (project_root / "build.gradle.kts").exists()
+    )
+    if not has_build_config:
+        return False, f"No build configuration (pom.xml, build.gradle, build.gradle.kts) found in {project_root}"
+
+    try:
+        source_file.relative_to(module_root)
+    except ValueError:
+        return False, f"Source file {source_file} is outside the module root {module_root}"
+
+    # Validate package declaration matches directory structure
+    package_name = _parse_package_declaration(source_file)
+    if package_name is not None:
+        expected_dir = module_root / Path(*package_name.split("."))
+        actual_dir = source_file.parent
+        if actual_dir.resolve() != expected_dir.resolve():
+            return False, (
+                f"Package declaration '{package_name}' does not match directory structure. "
+                f"Expected file at {expected_dir}, but found at {actual_dir}"
+            )
+
+    return True, ""
+
+
+def _parse_package_declaration(source_file: Path) -> str | None:
+    """Extract the package name from a Java source file, or None if no package declaration."""
+    try:
+        content = source_file.read_text(encoding="utf-8")
+    except Exception:
+        return None
+
+    for line in content.split("\n"):
+        stripped = line.strip()
+        if stripped.startswith("package "):
+            return stripped[8:].rstrip(";").strip()
+        # Skip comments and blank lines at the top of the file
+        if (
+            stripped
+            and not stripped.startswith("//")
+            and not stripped.startswith("/*")
+            and not stripped.startswith("*")
+        ):
+            break
+    return None
+
+
+def infer_java_module_root(source_file: Path, project_root: Path | None = None) -> Path:
+    """Infer the correct Java module root (source root) for a source file.
+
+    If project_root is None, walks up from source_file to find a build config.
+    Then uses find_source_root() from build_tools, falling back to
+    project_root/src/main/java, then project_root itself.
+    """
+    source_file = source_file.resolve()
+
+    if project_root is None:
+        project_root = _find_project_root_from_file(source_file)
+    else:
+        project_root = project_root.resolve()
+
+    if project_root is None:
+        return source_file.parent
+
+    from codeflash.languages.java.build_tools import find_source_root
+
+    source_root = find_source_root(project_root)
+    if source_root is not None:
+        return source_root
+
+    # Fall back to standard Maven layout
+    standard_src = project_root / "src" / "main" / "java"
+    if standard_src.exists():
+        return standard_src
+
+    return project_root
+
+
+def _find_project_root_from_file(source_file: Path) -> Path | None:
+    """Walk up from source_file to find a directory with a build config."""
+    current = source_file.parent
+    while current != current.parent:
+        if (current / "pom.xml").exists():
+            return current
+        if (current / "build.gradle").exists() or (current / "build.gradle.kts").exists():
+            return current
+        current = current.parent
+    return None