fix(reporter): pre-fill the GitHub issue form with a crash summary

cr-core/src/main/java/org/terasology/crashreporter/GlobalProperties.java

@@ -18,6 +18,7 @@ public enum KEY {
         SUPPORT_FORUM_LINK,
         JOIN_DISCORD_LINK,
         REPORT_ISSUE_LINK,
+        REPORT_ISSUE_TEMPLATE,
 
         RES_BANNER_IMAGE,
         RES_SERVER_ICON,

cr-core/src/main/java/org/terasology/crashreporter/RootPanel.java

@@ -74,7 +74,13 @@ public String get() {
             }
         });
         pages.add(uploadPanel);
-        pages.add(new FinalActionsPanel(properties, new Supplier<URL>() {
+        pages.add(new FinalActionsPanel(properties, exception, new Supplier<String>() {
+
+            @Override
+            public String get() {
+                return errorMessagePanel.getLog();
+            }
+        }, new Supplier<URL>() {
 
             @Override
             public URL get() {

cr-core/src/main/java/org/terasology/crashreporter/pages/FinalActionsPanel.java

@@ -39,6 +39,10 @@ public class FinalActionsPanel extends JPanel {
 
     private static final long serialVersionUID = 2639334979749507943L;
 
+    private final Throwable exception;
+
+    private final Supplier<String> logTextSupplier;
+
     private final Supplier<URL> uploadedFile;
 
     private final JTextArea linkText;
@@ -47,8 +51,11 @@ public class FinalActionsPanel extends JPanel {
 
     private boolean pageComplete;
 
-    public FinalActionsPanel(GlobalProperties properties, Supplier<URL> uploadedFile) {
+    public FinalActionsPanel(GlobalProperties properties, Throwable exception, Supplier<String> logTextSupplier,
+                              Supplier<URL> uploadedFile) {
 
+        this.exception = exception;
+        this.logTextSupplier = logTextSupplier;
         this.uploadedFile = uploadedFile;
 
         setLayout(new BorderLayout(0, 10));
@@ -89,7 +96,20 @@ public void actionPerformed(ActionEvent e) {
 
             @Override
             public void actionPerformed(ActionEvent e) {
-                openInBrowser(properties.get(KEY.REPORT_ISSUE_LINK));
+                CrashSummary summary = CrashSummary.extract(exception, logTextSupplier.get());
+                String baseUrl = properties.get(KEY.REPORT_ISSUE_LINK);
+                String template = properties.get(KEY.REPORT_ISSUE_TEMPLATE);
+                String link;
+                if (template != null && !template.isEmpty()) {
+                    // The downstream app has its own issue *form* - land the summary in its real
+                    // fields instead of overwriting the whole thing with a bespoke body.
+                    link = GitHubIssueLinkBuilder.build(baseUrl, template, summary.buildTitle(),
+                            summary.buildIssueFormFields(uploadedFile.get()));
+                } else {
+                    link = GitHubIssueLinkBuilder.build(baseUrl, summary.buildTitle(),
+                            summary.buildBody(uploadedFile.get()));
+                }
+                openInBrowser(link);
                 pageComplete = true;
                 firePropertyChange("pageComplete", !pageComplete, pageComplete);
             }

cr-core/src/main/java/org/terasology/crashreporter/pages/GitHubIssueLinkBuilder.java

@@ -0,0 +1,61 @@
+// Copyright 2026 The Terasology Foundation
+// SPDX-License-Identifier: Apache-2.0
+
+package org.terasology.crashreporter.pages;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URLEncoder;
+import java.util.Map;
+
+/**
+ * Builds a GitHub new-issue URL, pre-filled either via the classic {@code title}/{@code body} query
+ * parameters (works against any repo, regardless of what issue templates it has - the safe default),
+ * or, when a downstream app has one, via an issue *form*'s own field IDs (see
+ * {@link org.terasology.crashreporter.GlobalProperties.KEY#REPORT_ISSUE_TEMPLATE}) - a
+ * {@code template=} query parameter plus one parameter per field ID, landing the crash summary in
+ * the repo's own real template instead of overwriting it with a bespoke body.
+ */
+public final class GitHubIssueLinkBuilder {
+
+    private GitHubIssueLinkBuilder() {
+    }
+
+    public static String build(String baseUrl, String title, String body) {
+        if (baseUrl == null) {
+            return null;
+        }
+        String query = "title=" + encode(title) + "&body=" + encode(body);
+        return baseUrl + (baseUrl.contains("?") ? "&" : "?") + query;
+    }
+
+    /**
+     * @param template the issue form's filename (e.g. {@code "crash-bug-report.yml"}), as it appears
+     *         under {@code .github/ISSUE_TEMPLATE/} in the target repo
+     * @param fields field ID to value - entries with a {@code null}/empty value are omitted, leaving
+     *         that field for the user to fill in themselves rather than pre-filling it blank
+     */
+    public static String build(String baseUrl, String template, String title, Map<String, String> fields) {
+        if (baseUrl == null) {
+            return null;
+        }
+        StringBuilder query = new StringBuilder("template=").append(encode(template))
+                .append("&title=").append(encode(title));
+        for (Map.Entry<String, String> field : fields.entrySet()) {
+            String value = field.getValue();
+            if (value == null || value.isEmpty()) {
+                continue;
+            }
+            query.append('&').append(field.getKey()).append('=').append(encode(value));
+        }
+        return baseUrl + (baseUrl.contains("?") ? "&" : "?") + query;
+    }
+
+    private static String encode(String value) {
+        try {
+            return URLEncoder.encode(value, "UTF-8");
+        } catch (UnsupportedEncodingException e) {
+            // UTF-8 is a standard charset every JVM implementation is required to support.
+            throw new AssertionError(e);
+        }
+    }
+}

cr-core/src/test/java/org/terasology/crashreporter/pages/CrashSummaryTest.java

@@ -0,0 +1,232 @@
+// Copyright 2026 The Terasology Foundation
+// SPDX-License-Identifier: Apache-2.0
+
+package org.terasology.crashreporter.pages;
+
+import org.junit.jupiter.api.Test;
+
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ * Regression tests for #53 item 3: "Report Issue" opened a blank GitHub form instead of one
+ * pre-filled with the crash summary.
+ */
+class CrashSummaryTest {
+
+    private static final String LOG_TEXT =
+            "10:00:00.000 [main] INFO  o.t.e.version.TerasologyVersion - "
+                    + "[buildNumber=42, buildId=42, buildTag=Terasology-42, buildUrl=, jobName=Terasology/engine/develop, "
+                    + "dateTime=2026-08-20, displayVersion=Aeternum, engineVersion=5.4.0-SNAPSHOT]\n"
+                    + "10:00:00.100 [main] INFO  o.t.e.core.TerasologyEngine - OS: Linux, arch: amd64, version: 6.12.85\n"
+                    + "10:00:01.000 [main] INFO  o.t.e.core.modes.loadProcesses.RegisterMods - Activating module: engine:5.4.0-SNAPSHOT\n"
+                    + "10:00:01.010 [main] INFO  o.t.e.core.modes.loadProcesses.RegisterMods - Activating module: CoreAssets:2.4.0\n"
+                    + "10:00:01.020 [main] INFO  o.t.e.core.modes.loadProcesses.RegisterMods - Activating module: CoreAssets:2.4.0\n";
+
+    @Test
+    void extractsEngineAndDisplayVersion() {
+        CrashSummary summary = CrashSummary.extract(new RuntimeException("boom"), LOG_TEXT);
+        String body = summary.buildBody(null);
+
+        assertTrue(body.contains("5.4.0-SNAPSHOT"), "Expected the engine version in the body, got: " + body);
+        assertTrue(body.contains("Aeternum"), "Expected the display version in the body, got: " + body);
+    }
+
+    @Test
+    void extractsActiveModulesAndDeduplicates() {
+        CrashSummary summary = CrashSummary.extract(new RuntimeException("boom"), LOG_TEXT);
+        String body = summary.buildBody(null);
+
+        assertTrue(body.contains("engine:5.4.0-SNAPSHOT"), "Expected engine module, got: " + body);
+        // Occurs twice in the log (duplicate "Activating module" line) - should appear once in the body.
+        int occurrences = body.split("CoreAssets:2\\.4\\.0", -1).length - 1;
+        assertEquals(1, occurrences, "Expected the duplicate module line deduplicated, got: " + body);
+    }
+
+    @Test
+    void missingVersionAndModulesDegradeGracefullyInsteadOfFailing() {
+        CrashSummary summary = CrashSummary.extract(new RuntimeException("boom"), "no relevant lines here");
+        String body = summary.buildBody(null);
+
+        assertTrue(body.contains("unknown"), "Expected a fallback for a missing version, got: " + body);
+        assertTrue(body.contains("none found in logs"), "Expected a fallback for an empty module list, got: " + body);
+    }
+
+    @Test
+    void titleUsesExceptionClassAndMessage() {
+        CrashSummary summary = CrashSummary.extract(new IllegalStateException("world was null"), LOG_TEXT);
+
+        assertEquals("Crash: IllegalStateException: world was null", summary.buildTitle());
+    }
+
+    @Test
+    void bodyIncludesTheExceptionExtract() {
+        CrashSummary summary = CrashSummary.extract(new RuntimeException("kaboom"), LOG_TEXT);
+        String body = summary.buildBody(null);
+
+        assertTrue(body.contains("kaboom"), "Expected the exception message in the body, got: " + body);
+        assertTrue(body.contains("RuntimeException"), "Expected the exception type in the body, got: " + body);
+    }
+
+    @Test
+    void bodyIncludesThePastebinLinkWhenUploaded() throws MalformedURLException {
+        CrashSummary summary = CrashSummary.extract(new RuntimeException("boom"), LOG_TEXT);
+        URL link = new URL("https://pastebin.com/abc123");
+
+        String body = summary.buildBody(link);
+
+        assertTrue(body.contains("https://pastebin.com/abc123"), "Expected the PasteBin link in the body, got: " + body);
+    }
+
+    @Test
+    void bodyNotesWhenUploadWasSkipped() {
+        CrashSummary summary = CrashSummary.extract(new RuntimeException("boom"), LOG_TEXT);
+
+        String body = summary.buildBody(null);
+
+        assertFalse(body.contains("null"), "A skipped upload must not leak the literal string \"null\" into the body: " + body);
+        assertTrue(body.contains("not uploaded"), "Expected a note that upload was skipped, got: " + body);
+    }
+
+    // Regression: ErrorMessagePanel#getLog() combines every log tab, not just the one that
+    // triggered the report, but only the in-process exception ever made it into the pre-filled
+    // issue - an exception logged in a different tab (e.g. an earlier init-time failure) was
+    // silently left out even though it was right there in the combined text. All exceptions - the
+    // primary one and every other one found - are listed together, one labeled code block each
+    // (full trace, not just a one-line header - a real fix needs the actual trace), before
+    // "### Environment", not split across two separate sections.
+    @Test
+    void bodyListsExceptionsFoundInOtherLogTabsWithTheirFullTraceNamingTheTab() {
+        String combinedLog = "=== Terasology-init.log ===\n" + LOG_TEXT
+                + "\n=== Terasology-game.log ===\n"
+                + "10:10:05.123 [main] ERROR o.t.e.core.TerasologyEngine - Uncaught exception in main loop\n"
+                + "java.lang.NullPointerException: world was null\n"
+                + "\tat org.terasology.engine.core.TerasologyEngine.run(TerasologyEngine.java:200)\n";
+
+        CrashSummary summary = CrashSummary.extract(new RuntimeException("boom"), combinedLog);
+        String body = summary.buildBody(null);
+
+        assertTrue(body.contains("### Exceptions"), "Expected a single unified exceptions section, got: " + body);
+        assertTrue(body.contains("**Terasology-game.log**\n\n```\n"
+                        + "10:10:05.123 [main] ERROR o.t.e.core.TerasologyEngine - Uncaught exception in main loop\n"
+                        + "java.lang.NullPointerException: world was null\n"
+                        + "\tat org.terasology.engine.core.TerasologyEngine.run(TerasologyEngine.java:200)\n```"),
+                "Expected the other tab's exception as its own labeled block, with the line logged right before it and the full "
+                        + "trace, got: " + body);
+        int exceptionsIndex = body.indexOf("### Exceptions");
+        int environmentIndex = body.indexOf("### Environment");
+        assertTrue(exceptionsIndex >= 0 && environmentIndex > exceptionsIndex,
+                "Expected \"### Exceptions\" before \"### Environment\", got: " + body);
+    }
+
+    @Test
+    void bodyAttributesThePrimaryExceptionToItsOwnTabInsteadOfListingItTwice() {
+        RuntimeException primary = new RuntimeException("boom");
+        // The crash is very often also logged (by the crashed process itself) in one of its own
+        // log tabs - that's the same exception, not another one, and must not be listed twice. It's
+        // also the *real* trace (see the class javadoc on macOS reconstruction), so it must be used
+        // in preference to the exception object's own (possibly fake) trace.
+        String combinedLog = "=== Terasology-game.log ===\n"
+                + primary + "\n"
+                + "\tat org.terasology.engine.core.TerasologyEngine.run(TerasologyEngine.java:200)\n";
+
+        CrashSummary summary = CrashSummary.extract(primary, combinedLog);
+        String body = summary.buildBody(null);
+
+        assertTrue(body.contains("**Terasology-game.log**\n\n```\njava.lang.RuntimeException: boom\n"
+                        + "\tat org.terasology.engine.core.TerasologyEngine.run(TerasologyEngine.java:200)\n```"),
+                "Expected the primary exception's block attributed to the tab it was found in, using that tab's real trace, got: "
+                        + body);
+        int blocks = body.split("\\*\\*Terasology-game\\.log\\*\\*", -1).length - 1;
+        assertEquals(1, blocks, "Expected exactly one block - the primary exception must not also be listed as an \"other\" one: "
+                + body);
+    }
+
+    @Test
+    void bodyIncludesOnlyTheLastFiveLinesLoggedBeforeTheException() {
+        StringBuilder combinedLog = new StringBuilder("=== Terasology-game.log ===\n");
+        for (int i = 1; i <= 8; i++) {
+            combinedLog.append("log line ").append(i).append('\n');
+        }
+        combinedLog.append("java.lang.NullPointerException: world was null\n")
+                .append("\tat org.terasology.engine.core.TerasologyEngine.run(TerasologyEngine.java:200)\n");
+
+        CrashSummary summary = CrashSummary.extract(new RuntimeException("boom"), combinedLog.toString());
+        String body = summary.buildBody(null);
+
+        assertFalse(body.contains("log line 1\n") || body.contains("log line 2\n") || body.contains("log line 3\n"),
+                "Expected only the last 5 lines of context, not all 8, got: " + body);
+        assertTrue(body.contains("log line 4\nlog line 5\nlog line 6\nlog line 7\nlog line 8\n"
+                        + "java.lang.NullPointerException: world was null"),
+                "Expected the last 5 lines directly before the exception's header, got: " + body);
+    }
+
+    @Test
+    void bodyFallsBackToTheExceptionsOwnTraceWhenNotFoundInAnyTab() {
+        RuntimeException primary = new RuntimeException("boom");
+        CrashSummary summary = CrashSummary.extract(primary, LOG_TEXT);
+        String body = summary.buildBody(null);
+
+        assertTrue(body.contains("**this crash**\n\n```\njava.lang.RuntimeException: boom\n"),
+                "Expected a fallback label and the exception's own trace when it isn't found in any log tab, got: " + body);
+        assertTrue(body.contains(CrashSummaryTest.class.getName()),
+                "Expected this test's own stack frame in the fallback trace, got: " + body);
+    }
+
+    // buildIssueFormFields() feeds GitHubIssueLinkBuilder's template-based overload (see
+    // GitHubIssueLinkBuilderTest) - used instead of buildBody() when a downstream app has configured
+    // REPORT_ISSUE_TEMPLATE, landing the summary in that issue form's own fields.
+    @Test
+    void issueFormFieldsIncludeVersionOsAndTheExceptionBlocks() {
+        CrashSummary summary = CrashSummary.extract(new RuntimeException("boom"), LOG_TEXT);
+        Map<String, String> fields = summary.buildIssueFormFields(null);
+
+        assertEquals("5.4.0-SNAPSHOT (Aeternum)", fields.get("terasology_version"));
+        assertTrue(fields.get("operating_system").contains(System.getProperty("os.name")), fields.get("operating_system"));
+        assertEquals(System.getProperty("java.version"), fields.get("java_version"));
+        assertTrue(fields.get("actual_behavior").contains("RuntimeException: boom"), fields.get("actual_behavior"));
+    }
+
+    @Test
+    void issueFormFieldsOmitVersionWhenNotFoundInsteadOfSayingUnknown() {
+        CrashSummary summary = CrashSummary.extract(new RuntimeException("boom"), "no relevant lines here");
+        Map<String, String> fields = summary.buildIssueFormFields(null);
+
+        // Unlike buildBody()'s "unknown" fallback, an omitted field is left blank in the actual issue
+        // form for the user to fill in themselves - "unknown" pre-filled into a real form field would
+        // read as if the reporter deliberately couldn't tell, not as an untouched field.
+        assertNull(fields.get("terasology_version"), "Expected no terasology_version entry, got: " + fields);
+    }
+
+    @Test
+    void issueFormFieldsOmitLogDetailsWhenUploadWasSkipped() {
+        CrashSummary summary = CrashSummary.extract(new RuntimeException("boom"), LOG_TEXT);
+        Map<String, String> fields = summary.buildIssueFormFields(null);
+
+        assertNull(fields.get("log_details"), "Expected no log_details entry when nothing was uploaded, got: " + fields);
+    }
+
+    @Test
+    void issueFormFieldsIncludeThePastebinLinkWhenUploaded() throws MalformedURLException {
+        CrashSummary summary = CrashSummary.extract(new RuntimeException("boom"), LOG_TEXT);
+        URL link = new URL("https://pastebin.com/abc123");
+
+        Map<String, String> fields = summary.buildIssueFormFields(link);
+
+        assertTrue(fields.get("log_details").contains("https://pastebin.com/abc123"), fields.get("log_details"));
+    }
+
+    @Test
+    void issueFormFieldsIncludeActiveModulesUnderAdditionalContext() {
+        CrashSummary summary = CrashSummary.extract(new RuntimeException("boom"), LOG_TEXT);
+        Map<String, String> fields = summary.buildIssueFormFields(null);
+
+        assertTrue(fields.get("additional_context").contains("engine:5.4.0-SNAPSHOT"), fields.get("additional_context"));
+    }
+}