test(maven/analyze): add tests for PropertySources and parent POM resolution

Cover the new property source tracking and parent chain resolution added
in the previous commit:

- PropertySources is attributed to the correct file for both single-pom
  and directory (analyzeAllPoms) analysis paths
- Properties declared in a parent POM outside the project tree (../pom.xml)
  are found via resolveUnknownProperties and attributed to their source
- mergeProperty first-definition-wins and conflict behaviour
- resolveUnknownProperties returns correct value/source for a parent chain
  property and empty slice when the property is absent

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

Author: dnegreira

pkg/languages/java/maven/integration_test.go

@@ -681,3 +681,239 @@ func TestConvertDependenciesToPatches(t *testing.T) {
 		})
 	}
 }
+
+// pomWithParentAndProp returns a parent POM that declares a property.
+func pomWithParentAndProp(propName, propValue string) string {
+	return `<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>com.example</groupId>
+  <artifactId>parent</artifactId>
+  <version>1.0.0</version>
+  <packaging>pom</packaging>
+  <properties>
+    <` + propName + `>` + propValue + `</` + propName + `>
+  </properties>
+</project>`
+}
+
+// pomWithRelativeParent returns a POM that points at a parent via <relativePath>.
+func pomWithRelativeParent(relativePath string) string {
+	return `<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.example</groupId>
+    <artifactId>parent</artifactId>
+    <version>1.0.0</version>
+    <relativePath>` + relativePath + `</relativePath>
+  </parent>
+  <groupId>com.example</groupId>
+  <artifactId>child</artifactId>
+  <version>1.0.0</version>
+</project>`
+}
+
+// TestAnalyze_PropertySources_SinglePom checks that properties defined in the
+// analysed pom.xml itself are attributed to that file.
+func TestAnalyze_PropertySources_SinglePom(t *testing.T) {
+	dir := t.TempDir()
+	pomContent := `<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>com.example</groupId>
+  <artifactId>test</artifactId>
+  <version>1.0.0</version>
+  <properties>
+    <netty.version>4.1.100.Final</netty.version>
+  </properties>
+</project>`
+	pomPath := filepath.Join(dir, "pom.xml")
+	writeFile(t, pomPath, pomContent)
+
+	ma := &MavenAnalyzer{}
+	result, err := ma.Analyze(t.Context(), pomPath)
+	if err != nil {
+		t.Fatalf("Analyze: %v", err)
+	}
+
+	if src := result.PropertySources["netty.version"]; src != "pom.xml" {
+		t.Errorf("PropertySources[netty.version] = %q, want %q", src, "pom.xml")
+	}
+}
+
+// TestAnalyze_PropertySources_DirectoryAnalysis checks that analyzeAllPoms
+// attributes each property to the POM file that declares it.
+func TestAnalyze_PropertySources_DirectoryAnalysis(t *testing.T) {
+	dir := t.TempDir()
+	writeFile(t, filepath.Join(dir, "pom.xml"), `<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>com.example</groupId><artifactId>root</artifactId><version>1.0.0</version>
+  <properties><root.prop>1.0</root.prop></properties>
+</project>`)
+	writeFile(t, filepath.Join(dir, "module-a", "pom.xml"), `<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>com.example</groupId><artifactId>module-a</artifactId><version>1.0.0</version>
+  <properties><module.prop>2.0</module.prop></properties>
+</project>`)
+
+	ma := &MavenAnalyzer{}
+	result, err := ma.Analyze(t.Context(), dir)
+	if err != nil {
+		t.Fatalf("Analyze: %v", err)
+	}
+
+	if src := result.PropertySources["root.prop"]; src != "pom.xml" {
+		t.Errorf("PropertySources[root.prop] = %q, want %q", src, "pom.xml")
+	}
+	if src := result.PropertySources["module.prop"]; src != filepath.Join("module-a", "pom.xml") {
+		t.Errorf("PropertySources[module.prop] = %q, want %q", src, filepath.Join("module-a", "pom.xml"))
+	}
+}
+
+// TestAnalyze_PropertySources_ParentPomOutsideTree checks that a property
+// declared in a parent POM referenced via <parent><relativePath> (potentially
+// outside the project root) is found and attributed correctly.
+func TestAnalyze_PropertySources_ParentPomOutsideTree(t *testing.T) {
+	root := t.TempDir()
+	// Project layout: root/lib/pom.xml → parent is root/pom.xml
+	parentPom := filepath.Join(root, "pom.xml")
+	childPom := filepath.Join(root, "lib", "pom.xml")
+
+	writeFile(t, parentPom, pomWithParentAndProp("netty.version", "4.1.100.Final"))
+	writeFile(t, childPom, pomWithRelativeParent("../pom.xml"))
+
+	ma := &MavenAnalyzer{}
+	result, err := ma.Analyze(t.Context(), childPom)
+	if err != nil {
+		t.Fatalf("Analyze: %v", err)
+	}
+
+	if v := result.Properties["netty.version"]; v != "4.1.100.Final" {
+		t.Errorf("Properties[netty.version] = %q, want 4.1.100.Final", v)
+	}
+	if src := result.PropertySources["netty.version"]; src != "../pom.xml" {
+		t.Errorf("PropertySources[netty.version] = %q, want %q", src, "../pom.xml")
+	}
+}
+
+// TestAnalyze_PropertySources_ParentPomOutsideTree_Directory checks the same
+// for directory-mode analysis (analyzeAllPoms path).
+func TestAnalyze_PropertySources_ParentPomOutsideTree_Directory(t *testing.T) {
+	root := t.TempDir()
+	parentPom := filepath.Join(root, "pom.xml")
+	childDir := filepath.Join(root, "lib")
+	childPom := filepath.Join(childDir, "pom.xml")
+
+	writeFile(t, parentPom, pomWithParentAndProp("netty.version", "4.1.100.Final"))
+	// Child POM references a dep via the property so PropertyUsage is populated.
+	writeFile(t, childPom, `<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.example</groupId>
+    <artifactId>parent</artifactId>
+    <version>1.0.0</version>
+    <relativePath>../pom.xml</relativePath>
+  </parent>
+  <groupId>com.example</groupId>
+  <artifactId>child</artifactId>
+  <version>1.0.0</version>
+  <dependencyManagement>
+    <dependencies>
+      <dependency>
+        <groupId>io.netty</groupId>
+        <artifactId>netty-all</artifactId>
+        <version>${netty.version}</version>
+      </dependency>
+    </dependencies>
+  </dependencyManagement>
+</project>`)
+
+	ma := &MavenAnalyzer{}
+	result, err := ma.Analyze(t.Context(), childDir)
+	if err != nil {
+		t.Fatalf("Analyze: %v", err)
+	}
+
+	if v := result.Properties["netty.version"]; v != "4.1.100.Final" {
+		t.Errorf("Properties[netty.version] = %q, want 4.1.100.Final", v)
+	}
+	if src := result.PropertySources["netty.version"]; src != "../pom.xml" {
+		t.Errorf("PropertySources[netty.version] = %q, want %q", src, "../pom.xml")
+	}
+}
+
+// TestMergeProperty verifies first-definition-wins and no double-assignment.
+func TestMergeProperty(t *testing.T) {
+	result := &analyzer.AnalysisResult{
+		Properties:      make(map[string]string),
+		PropertySources: make(map[string]string),
+	}
+
+	if !mergeProperty(t.Context(), result, "k", "v1", "a.xml") {
+		t.Error("first merge should return true (newly added)")
+	}
+	if result.Properties["k"] != "v1" || result.PropertySources["k"] != "a.xml" {
+		t.Errorf("property not set correctly after first merge")
+	}
+
+	// Same value — no warning, returns false.
+	if mergeProperty(t.Context(), result, "k", "v1", "b.xml") {
+		t.Error("merge of same value should return false (already present)")
+	}
+	if result.PropertySources["k"] != "a.xml" {
+		t.Error("source should not change when property already present")
+	}
+
+	// Different value — conflict warning, still returns false, source unchanged.
+	if mergeProperty(t.Context(), result, "k", "v2", "c.xml") {
+		t.Error("conflicting merge should return false (already present)")
+	}
+	if result.Properties["k"] != "v1" {
+		t.Error("conflicting value should not overwrite existing")
+	}
+}
+
+// TestResolveUnknownProperties_ParentChain verifies that properties missing
+// from the scanned files are found by following <parent><relativePath>.
+func TestResolveUnknownProperties_ParentChain(t *testing.T) {
+	root := t.TempDir()
+	parentPom := filepath.Join(root, "pom.xml")
+	childPom := filepath.Join(root, "lib", "pom.xml")
+
+	writeFile(t, parentPom, pomWithParentAndProp("netty.version", "4.1.100.Final"))
+	writeFile(t, childPom, pomWithRelativeParent("../pom.xml"))
+
+	usage := map[string]int{"netty.version": 1, "already.found": 1}
+	known := map[string]string{"already.found": "1.0"} // pre-filled, should be skipped
+
+	results := resolveUnknownProperties(t.Context(), usage, known, childPom, filepath.Join(root, "lib"))
+
+	if len(results) != 1 {
+		t.Fatalf("expected 1 result, got %d", len(results))
+	}
+	pf := results[0]
+	if v := pf.Properties["netty.version"]; v != "4.1.100.Final" {
+		t.Errorf("Properties[netty.version] = %q, want 4.1.100.Final", v)
+	}
+	if pf.PomFile != "../pom.xml" {
+		t.Errorf("PomFile = %q, want %q", pf.PomFile, "../pom.xml")
+	}
+}
+
+// TestResolveUnknownProperties_NotFound verifies that a property absent from
+// the entire parent chain returns no results (not an error).
+func TestResolveUnknownProperties_NotFound(t *testing.T) {
+	dir := t.TempDir()
+	writeFile(t, filepath.Join(dir, "pom.xml"), minimalPOM)
+
+	usage := map[string]int{"does.not.exist": 1}
+	results := resolveUnknownProperties(t.Context(), usage, nil, filepath.Join(dir, "pom.xml"), dir)
+
+	if len(results) != 0 {
+		t.Errorf("expected 0 results for unknown property, got %d", len(results))
+	}
+}