Parts now have access to all parts via a EmbeddablePartsMap.

lib/src/main/groovy/com/jessebrault/ssg/part/EmbeddablePart.groovy

@@ -18,12 +18,15 @@ class EmbeddablePart {
     @Nullable
     private final EmbeddableText text
 
+    private final Collection<Part> allParts
+
     String render(Map binding = [:]) {
         def result = part.type.renderer.render(
                 this.part,
                 binding,
                 this.globals,
-                this.text
+                this.text,
+                this.allParts
         )
         if (result.v1.size() > 0) {
             this.onDiagnostics.call(result.v1)

lib/src/main/groovy/com/jessebrault/ssg/part/EmbeddablePartsMap.groovy

@@ -20,7 +20,7 @@ class EmbeddablePartsMap {
         Objects.requireNonNull(globals)
         Objects.requireNonNull(onDiagnostics)
         parts.each {
-            this.put(it.path, new EmbeddablePart(it, globals, onDiagnostics, text))
+            this.put(it.path, new EmbeddablePart(it, globals, onDiagnostics, text, parts))
         }
     }
 

lib/src/main/groovy/com/jessebrault/ssg/part/GspPartRenderer.groovy

@@ -18,22 +18,30 @@ class GspPartRenderer implements PartRenderer {
             Part part,
             Map binding,
             Map globals,
-            @Nullable EmbeddableText text = null
+            @Nullable EmbeddableText text = null,
+            Collection<Part> allParts
     ) {
         Objects.requireNonNull(part)
         Objects.requireNonNull(binding)
         Objects.requireNonNull(globals)
+        Objects.requireNonNull(allParts)
+        def embeddedPartDiagnostics = []
         try {
             def result = engine.createTemplate(part.text).make([
                     binding: binding,
                     globals: globals,
+                    parts: new EmbeddablePartsMap(allParts, globals, embeddedPartDiagnostics.&addAll, text),
                     tagBuilder: new DynamicTagBuilder(),
                     text: text
             ])
             new Tuple2<>([], result.toString())
         } catch (Exception e) {
+            def diagnostic = new Diagnostic(
+                    "An exception occurred while rendering part ${ part.path }:\n${ e }",
+                    e
+            )
             new Tuple2<>(
-                    [new Diagnostic("An exception occurred while rendering part ${ part.path }:\n${ e }", e)],
+                    [diagnostic, *embeddedPartDiagnostics],
                     ''
             )
         }

lib/src/main/groovy/com/jessebrault/ssg/part/PartRenderer.groovy

@@ -10,7 +10,8 @@ interface PartRenderer {
             Part part,
             Map binding,
             Map globals,
-            @Nullable EmbeddableText text
+            @Nullable EmbeddableText text,
+            Collection<Part> allParts
     )
 
 }

lib/src/test/groovy/com/jessebrault/ssg/part/GspPartRendererTests.groovy

@@ -3,7 +3,9 @@ package com.jessebrault.ssg.part
 import com.jessebrault.ssg.Diagnostic
 import com.jessebrault.ssg.text.*
 import org.junit.jupiter.api.Test
+import org.mockito.Mock
 
+import static com.jessebrault.ssg.testutil.DiagnosticsUtil.getDiagnosticsMessageSupplier
 import static org.junit.jupiter.api.Assertions.assertEquals
 import static org.junit.jupiter.api.Assertions.assertTrue
 import static org.mockito.ArgumentMatchers.any
@@ -28,7 +30,7 @@ class GspPartRendererTests {
     @Test
     void rendersWithNoBindingOrGlobals() {
         def part = new Part('', null, 'Hello, World!')
-        def r = this.renderer.render(part, [:], [:], null)
+        def r = this.renderer.render(part, [:], [:], null, [part])
         assertTrue(r.v1.size() == 0)
         assertEquals('Hello, World!', r.v2)
     }
@@ -36,7 +38,13 @@ class GspPartRendererTests {
     @Test
     void rendersWithBinding() {
         def part = new Part('', null, "<%= binding['greeting'] %>")
-        def r = this.renderer.render(part, [greeting: 'Hello, World!'], [:], null)
+        def r = this.renderer.render(
+                part,
+                [greeting: 'Hello, World!'],
+                [:],
+                null,
+                [part]
+        )
         assertTrue(r.v1.size() == 0)
         assertEquals('Hello, World!', r.v2)
     }
@@ -44,7 +52,13 @@ class GspPartRendererTests {
     @Test
     void rendersWithGlobals() {
         def part = new Part(null, null, "<%= globals['greeting'] %>")
-        def r = this.renderer.render(part, [:], [greeting: 'Hello, World!'], null)
+        def r = this.renderer.render(
+                part,
+                [:],
+                [greeting: 'Hello, World!'],
+                null,
+                [part]
+        )
         assertTrue(r.v1.size() == 0)
         assertEquals('Hello, World!', r.v2)
     }
@@ -61,7 +75,8 @@ class GspPartRendererTests {
                         mockRenderableText('Hello, World!'),
                         [:],
                         { Collection<Diagnostic> diagnostics -> textDiagnostics.addAll(diagnostics) }
-                )
+                ),
+                [part]
         )
         assertTrue(textDiagnostics.isEmpty())
         assertTrue(r.v1.isEmpty())
@@ -71,9 +86,19 @@ class GspPartRendererTests {
     @Test
     void tagBuilderAvailable() {
         def part = new Part('', null, '<%= tagBuilder.test() %>')
-        def r = this.renderer.render(part, [:], [:], null)
+        def r = this.renderer.render(part, [:], [:], null, [part])
         assertTrue(r.v1.isEmpty())
         assertEquals('<test />', r.v2)
     }
 
+    @Test
+    void allPartsAvailable() {
+        def partType = new PartType(['.gsp'], this.renderer)
+        def part0 = new Part('part0.gsp', partType, '<%= parts["part1.gsp"].render() %>')
+        def part1 = new Part('part1.gsp', partType, 'Hello, World!')
+        def r = this.renderer.render(part0, [:], [:], null, [part0, part1])
+        assertTrue(r.v1.isEmpty(), getDiagnosticsMessageSupplier(r.v1))
+        assertEquals('Hello, World!', r.v2)
+    }
+
 }

lib/src/testFixtures/groovy/com/jessebrault/ssg/testutil/DiagnosticsUtil.groovy

@@ -0,0 +1,18 @@
+package com.jessebrault.ssg.testutil
+
+import com.jessebrault.ssg.Diagnostic
+
+class DiagnosticsUtil {
+
+    static Closure<String> getDiagnosticsMessageSupplier(Collection<Diagnostic> diagnostics) {
+        return {
+            diagnostics.collect {
+                def writer = new StringWriter()
+                it.exception.printStackTrace(new PrintWriter(writer))
+                def stackTrace = writer.toString()
+                "$it.message\n$stackTrace"
+            }.join('\n')
+        }
+    }
+
+}