Revamp Jelly completion suggestions

src/main/java/io/jenkins/stapler/idea/jelly/NamespaceUtil.java

@@ -0,0 +1,51 @@
+package io.jenkins.stapler.idea.jelly;
+
+import com.intellij.openapi.project.Project;
+import com.intellij.psi.PsiFile;
+import com.intellij.psi.PsiManager;
+import com.intellij.psi.search.FileTypeIndex;
+import com.intellij.psi.search.GlobalSearchScope;
+import com.intellij.psi.xml.XmlTag;
+import java.util.HashMap;
+import java.util.Map;
+import org.kohsuke.stapler.idea.language.JellyFileType;
+import org.kohsuke.stapler.idea.psi.JellyFile;
+
+public class NamespaceUtil {
+
+    /** Collects all namespaces (and prefixes) from .jelly files in the project */
+    public static Map<String, String> collectProjectNamespaces(Project project) {
+        Map<String, String> namespaces = new HashMap<>();
+
+        FileTypeIndex.processFiles(
+                JellyFileType.INSTANCE,
+                file -> {
+                    PsiFile psiFile = PsiManager.getInstance(project).findFile(file);
+                    if (psiFile instanceof JellyFile jellyFile) {
+                        XmlTag rootTag = jellyFile.getRootTag();
+                        if (rootTag != null) {
+                            String[] uris = rootTag.knownNamespaces();
+
+                            for (String uri : uris) {
+                                String prefix = rootTag.getPrefixByNamespace(uri);
+
+                                if (prefix == null || prefix.isEmpty()) {
+                                    continue;
+                                }
+
+                                // Ignore local prefixes as they're not for global usage
+                                if (prefix.equals("local") || prefix.equals("this")) {
+                                    continue;
+                                }
+
+                                namespaces.put(prefix, uri);
+                            }
+                        }
+                    }
+                    return true;
+                },
+                GlobalSearchScope.projectScope(project));
+
+        return namespaces;
+    }
+}

src/main/java/org/kohsuke/stapler/idea/descriptor/StaplerCustomJellyTagLibraryXmlNSDescriptor.java

@@ -79,21 +79,26 @@ private XmlElementDescriptor getElementDescriptor(String localName) {
         return null;
     }
 
+    /** Returns an empty array to disable IntelliJ's autocomplete */
+    @Override
+    @NotNull
+    public XmlElementDescriptor @NotNull [] getRootElementsDescriptors(@Nullable XmlDocument document) {
+        return new XmlElementDescriptor[0];
+    }
+
     /**
-     * Returns all the possible root elements.
+     * Returns all possible tags for the library.
      *
-     * <p>This appears to be used for code completion. When I returned an empty array, the code completion didn't show
-     * me anything.
+     * <p>This is used for generating autocomplete suggestions.
      */
-    @Override
     @NotNull
-    public XmlElementDescriptor @NotNull [] getRootElementsDescriptors(@Nullable XmlDocument document) {
-        List<XmlElementDescriptor> r = new ArrayList<>();
+    public StaplerCustomJellyTagfileXmlElementDescriptor @NotNull [] getTagDescriptors() {
+        List<StaplerCustomJellyTagfileXmlElementDescriptor> r = new ArrayList<>();
         for (PsiFile f : dir.getFiles()) {
             if (!isTagFile(f)) continue;
             if (f instanceof XmlFile) r.add(new StaplerCustomJellyTagfileXmlElementDescriptor(this, (XmlFile) f));
         }
-        return r.toArray(new XmlElementDescriptor[0]);
+        return r.toArray(new StaplerCustomJellyTagfileXmlElementDescriptor[0]);
     }
 
     private boolean isTagFile(PsiFile file) {

src/main/java/org/kohsuke/stapler/idea/icons/Icons.java

@@ -5,6 +5,7 @@
 
 /** @author Kohsuke Kawaguchi */
 public class Icons {
-    public static final Icon STAPLER = IconLoader.getIcon("/org/kohsuke/stapler/idea/icons/stapler.png", Icons.class);
+    public static final Icon COMPONENT =
+            IconLoader.getIcon("/org/kohsuke/stapler/idea/icons/component.svg", Icons.class);
     public static final Icon JELLY = IconLoader.getIcon("/org/kohsuke/stapler/idea/icons/jelly.svg", Icons.class);
 }

src/test/java/org/kohsuke/stapler/idea/JellyCompletionContributorTest.java

@@ -0,0 +1,101 @@
+package org.kohsuke.stapler.idea;
+
+import com.intellij.testFramework.fixtures.BasePlatformTestCase;
+
+public class JellyCompletionContributorTest extends BasePlatformTestCase {
+
+    @Override
+    protected String getTestDataPath() {
+        return "src/test/testData";
+    }
+
+    public void testDefaultTagLibrary() {
+        assertDefaultTagLibrary(
+                """
+            <?xml version="1.0" encoding="UTF-8"?>
+            <?jelly escape-by-default='true'?>
+            <j:jelly xmlns:j="jelly:core">
+                <l:b<caret>
+            </j:jelly>
+        """,
+                """
+            <?xml version="1.0" encoding="UTF-8"?>
+            <?jelly escape-by-default='true'?>
+            <j:jelly xmlns:j="jelly:core" xmlns:l="/lib/layout">
+                <l:basic />
+            </j:jelly>
+        """);
+    }
+
+    public void testRequiredAttributes() {
+        assertDefaultTagLibrary(
+                """
+            <?xml version="1.0" encoding="UTF-8"?>
+            <?jelly escape-by-default='true'?>
+            <j:jelly xmlns:j="jelly:core">
+                <l:req<caret>
+            </j:jelly>
+        """,
+                """
+            <?xml version="1.0" encoding="UTF-8"?>
+            <?jelly escape-by-default='true'?>
+            <j:jelly xmlns:j="jelly:core" xmlns:l="/lib/layout">
+                <l:required title="" />
+            </j:jelly>
+        """);
+    }
+
+    public void testInvokeBody() {
+        assertDefaultTagLibrary(
+                """
+            <?xml version="1.0" encoding="UTF-8"?>
+            <?jelly escape-by-default='true'?>
+            <j:jelly xmlns:j="jelly:core">
+                <l:child<caret>
+            </j:jelly>
+        """,
+                """
+            <?xml version="1.0" encoding="UTF-8"?>
+            <?jelly escape-by-default='true'?>
+            <j:jelly xmlns:j="jelly:core" xmlns:l="/lib/layout">
+                <l:children>
+                 \s
+                </l:children>
+            </j:jelly>
+        """);
+    }
+
+    public void testCustomTagLibrary() {
+        myFixture.copyDirectoryToProject("testlib", "testlib");
+        myFixture.configureByText(
+                "basic.jelly",
+                """
+            <?xml version="1.0" encoding="UTF-8"?>
+            <?jelly escape-by-default='true'?>
+            <j:jelly xmlns:j="jelly:core" xmlns:t="/testlib">
+                <t:t<caret>
+            </j:jelly>
+        """);
+
+        myFixture.completeBasic();
+
+        myFixture.checkResult(
+                """
+            <?xml version="1.0" encoding="UTF-8"?>
+            <?jelly escape-by-default='true'?>
+            <j:jelly xmlns:j="jelly:core" xmlns:t="/testlib">
+                <t:test />
+            </j:jelly>
+        """);
+    }
+
+    private void assertDefaultTagLibrary(String body, String expected) {
+        // Simulate the default tag libraries in core
+        myFixture.copyDirectoryToProject("lib", "lib");
+        myFixture.configureByText("basic.jelly", body);
+
+        myFixture.completeBasic();
+
+        myFixture.checkResult(expected);
+    }
+}

src/test/testData/lib/layout/basic.jelly

@@ -0,0 +1,4 @@
+<?jelly escape-by-default='true'?>
+<j:jelly xmlns:j="jelly:core">
+    <p>Test</p>
+</j:jelly>

src/test/testData/lib/layout/children.jelly

@@ -0,0 +1,4 @@
+<?jelly escape-by-default='true'?>
+<j:jelly xmlns:j="jelly:core" xmlns:d="jelly:define">
+    <d:invokeBody />
+</j:jelly>

src/test/testData/lib/layout/required.jelly

@@ -0,0 +1,7 @@
+<?jelly escape-by-default='true'?>
+<j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler">
+    <st:documentation>
+        <st:attribute name="title" use="required" />
+    </st:documentation>
+    <p>Test</p>
+</j:jelly>