Honor empty <relativePath/> in MavenPomDownloader

rewrite-maven/src/main/java/org/openrewrite/maven/internal/MavenPomDownloader.java

@@ -214,7 +214,11 @@ private List<Pom> getAncestryWithinProject(Pom projectPom, Map<Path, Pom> projec
             return null;
         }
         String relativePath = parent.getRelativePath();
-        if (StringUtils.isBlank(relativePath)) {
+        // An explicit empty <relativePath/> means "do not look for the parent locally"
+        if (relativePath != null && relativePath.isEmpty()) {
+            return null;
+        }
+        if (relativePath == null) {
             relativePath = "../pom.xml";
         }
         Path parentPath = projectPom.getSourcePath()
@@ -516,10 +520,12 @@ public Pom download(GroupArtifactVersion gav,
             }
         }
 
-        if (containingPom != null && containingPom.getRequested().getSourcePath() != null) {
+        // An explicit empty <relativePath/> means "do not look for the parent locally"
+        if (containingPom != null && containingPom.getRequested().getSourcePath() != null &&
+                !(relativePath != null && relativePath.isEmpty())) {
             // Maven POM §4.0.0 specifies that <relativePath> defaults to ".." when omitted.
             // See DefaultModelBuilder#readParentLocally in maven-model-builder.
-            String effectiveRelativePath = StringUtils.isBlank(relativePath) ? ".." : relativePath;
+            String effectiveRelativePath = relativePath == null ? ".." : relativePath;
             if (!effectiveRelativePath.contains(":")) {
                 Path folderContainingPom = containingPom.getRequested().getSourcePath().getParent();
                 if (folderContainingPom != null) {

rewrite-maven/src/test/java/org/openrewrite/maven/internal/MavenPomDownloaderTest.java

@@ -1055,6 +1055,103 @@ void canResolveDifferentVersionOfProjectPom() {
 
             assertDoesNotThrow(() -> downloader.download(gav, Objects.requireNonNull(pom.getParent()).getRelativePath(), resolvedPom, singletonList(nonexistentRepo)));
         }
+
+        @Issue("https://github.com/moderneinc/customer-requests/issues/1950")
+        @Test
+        void emptyRelativePathSkipsLocalParentLookup() {
+            // A local parent POM exists at ../pom.xml that matches the GAV,
+            // but the child specifies <relativePath/> (empty string) which means
+            // "do not look for the parent locally".
+            var gav = new GroupArtifactVersion("test", "parent", "1.0.0");
+
+            Path rootPomXml = Path.of("pom.xml");
+            Pom parentPom = Pom.builder()
+              .sourcePath(rootPomXml)
+              .repository(MAVEN_CENTRAL)
+              .parent(null)
+              .gav(new ResolvedGroupArtifactVersion(
+                MAVEN_CENTRAL.getUri(), "test", "parent", "1.0.0", null))
+              .build();
+
+            Path childPomXml = Path.of("child/pom.xml");
+            // Empty string for relativePath simulates <relativePath/>
+            Pom childPom = Pom.builder()
+              .sourcePath(childPomXml)
+              .repository(MAVEN_CENTRAL)
+              .parent(new Parent(gav, ""))
+              .gav(new ResolvedGroupArtifactVersion(
+                MAVEN_CENTRAL.getUri(), "test", "child", "1.0.0", null))
+              .build();
+
+            ResolvedPom resolvedPom = ResolvedPom.builder()
+              .requested(childPom)
+              .repositories(singletonList(MAVEN_CENTRAL))
+              .build();
+
+            Map<Path, Pom> pomsByPath = new HashMap<>();
+            pomsByPath.put(rootPomXml, parentPom);
+            pomsByPath.put(childPomXml, childPom);
+
+            MavenPomDownloader downloader = new MavenPomDownloader(pomsByPath, ctx);
+
+            // With empty relativePath, the downloader should NOT find the parent locally
+            // via relative path resolution, and should instead go to remote repos.
+            // Since the parent IS available on Maven Central, this should succeed
+            // by downloading from the remote repository, not by local path resolution.
+            assertDoesNotThrow(() -> downloader.download(gav, "", resolvedPom, singletonList(MAVEN_CENTRAL)));
+        }
+
+        @Issue("https://github.com/moderneinc/customer-requests/issues/1950")
+        @Test
+        void emptyRelativePathSkipsPathBasedLookupWithPlaceholderVersion() {
+            // A local parent POM exists at ../pom.xml, but the child specifies <relativePath/>
+            // (empty string) and references the parent with a placeholder version ${my.version}.
+            // Without the fix, the path-based lookup (stage 3) would default relativePath to "..",
+            // find the parent, and accept it because "${" in the version relaxes the version check.
+            // With the fix, stage 3 is skipped entirely due to empty relativePath.
+            var gav = new GroupArtifactVersion("test", "parent", "${my.version}");
+
+            Path rootPomXml = Path.of("pom.xml");
+            Pom parentPom = Pom.builder()
+              .sourcePath(rootPomXml)
+              .repository(MAVEN_CENTRAL)
+              .parent(null)
+              .gav(new ResolvedGroupArtifactVersion(
+                MAVEN_CENTRAL.getUri(), "test", "parent", "1.0.0", null))
+              .build();
+
+            Path childPomXml = Path.of("child/pom.xml");
+            Pom childPom = Pom.builder()
+              .sourcePath(childPomXml)
+              .repository(MAVEN_CENTRAL)
+              .parent(new Parent(gav, ""))
+              .gav(new ResolvedGroupArtifactVersion(
+                MAVEN_CENTRAL.getUri(), "test", "child", "1.0.0", null))
+              .build();
+
+            ResolvedPom resolvedPom = ResolvedPom.builder()
+              .requested(childPom)
+              .repositories(singletonList(MAVEN_CENTRAL))
+              .build();
+
+            Map<Path, Pom> pomsByPath = new HashMap<>();
+            pomsByPath.put(rootPomXml, parentPom);
+            pomsByPath.put(childPomXml, childPom);
+
+            String httpUrl = "http://%s.com".formatted(UUID.randomUUID());
+            MavenRepository nonexistentRepo = new MavenRepository("repo", httpUrl, null, null, false, null, null, null, null);
+
+            MavenPomDownloader downloader = new MavenPomDownloader(pomsByPath, ctx);
+
+            // With empty relativePath, the path-based lookup (stage 3) should be skipped.
+            // The placeholder ${my.version} can't be resolved via GAV iteration (stage 2)
+            // because the parent doesn't define my.version. Without the fix, stage 3 would
+            // find the parent at ../pom.xml and accept it (placeholder version relaxes the
+            // version check). With the fix, the download falls through to the remote repo
+            // and fails (IllegalArgumentException from the unresolved placeholder in the URI).
+            assertThrows(Exception.class,
+              () -> downloader.download(gav, "", resolvedPom, singletonList(nonexistentRepo)));
+        }
     }
 
     @Nested