[2447] Escape the block comment terminator when exporting a comment body

CHANGELOG.adoc

@@ -52,6 +52,8 @@ This also fixes `relatedFeature`, `sourceFeature` and `targetFeature`, which wer
 - https://github.com/eclipse-syson/syson/issues/2226[#2226] [import] Fix textual import of annotations on relationships so their `annotatedElement` is set and they are returned by `Element#getOwnedAnnotation()`.
 - https://github.com/eclipse-syson/syson/issues/2419[#2419] [export] Fix the export of the prefix metadata carried by the ends of a connector, which were dropped when those ends are declared inline.
 The ends of a connector created from a diagram are owned through an `EndFeatureMembership` and are exported inline, so their metadata, such as the `#original` and `#derive` of a requirement derivation, were lost.
+- https://github.com/eclipse-syson/syson/issues/2447[#2447] [export] Fix the export of a comment body containing `*/`, which closed the block comment early and produced a file that could not be parsed.
+The grammar defines a comment as a non greedy match up to the first `*/`, with no escape sequence and no nesting, so that sequence is exported as `* /` and a warning is reported, since the exported text is then not exactly the one that was written.
 - https://github.com/eclipse-syson/syson/issues/2340[#2340] [diagrams] Replace the name of the _New Perform action_ tool to _New Perform Action_ to be consistent with other tools.
 - https://github.com/eclipse-syson/syson/issues/2437[#2437] [metamodel] Fix elementId when creating a FlowDefinition
 - https://github.com/eclipse-syson/syson/issues/2384[#2384] [import] Fix the import of `TransitionUsage` using _start_ which now set the source to the `StateUsage` _start_ from the standard library instead of `ActionUsage` _start_ from the standard library.

backend/application/syson-application/src/test/java/org/eclipse/syson/sysml/textual/SysMLElementSerializerTest.java

@@ -1979,6 +1979,21 @@ public void portUsageFull() {
 
     }
 
+    @Test
+    public void documentationContainingACommentTerminator() {
+        PartUsage partUsage = this.builder.createWithName(PartUsage.class, "PartUsage1");
+        this.builder.createIn(Documentation.class, partUsage).setBody("Closing a block comment looks like */ in the code");
+
+        // The terminator is separated so it no longer closes the comment, which would leave the rest of the body
+        // exported as if it were SysML v2 code.
+        this.assertTextualFormEquals("""
+                part PartUsage1 {
+                    doc /* Closing a block comment looks like * / in the code */
+                }""", partUsage);
+        assertTrue(this.status.stream()
+                .anyMatch(reported -> reported.severity() == Severity.WARNING && reported.message().contains("closes a comment")));
+    }
+
     @Test
     public void documentation() {
 

backend/services/syson-sysml-metamodel-services/src/main/java/org/eclipse/syson/sysml/metamodel/services/textual/SysMLElementSerializer.java

@@ -170,6 +170,12 @@ public class SysMLElementSerializer extends SysmlSwitch<String> {
 
     private static final String SPACE = " ";
 
+    /** The sequence closing a block comment, which cannot appear inside a comment body. */
+    private static final String COMMENT_TERMINATOR = "*/";
+
+    /** The form the block comment terminator is exported as, so it no longer closes the comment. */
+    private static final String ESCAPED_COMMENT_TERMINATOR = "* /";
+
     private final String lineSeparator;
 
     private final String indentation;
@@ -2530,10 +2536,38 @@ private <T> T getDirectContainer(EObject element, java.lang.Class<T> expected) {
 
     private String getCommentBody(String body) {
         Appender subBuilder = this.newAppender();
-        subBuilder.append("/* ").append(body).append(" */");
+        subBuilder.append("/* ").append(this.escapeCommentTerminator(body)).append(" */");
         return subBuilder.toString();
     }
 
+    /**
+     * Replace the occurrences of the block comment terminator in a comment body.
+     * <p>
+     * The grammar defines a comment as {@code /*[\s\S]*?*}{@code /}, a non greedy match up to the first {@code *}
+     * {@code /}, with no escape sequence and no nesting, so that sequence cannot be represented inside a comment body.
+     * Left as it is, it closes the comment early and the rest of the body is exported as if it were SysML v2 code,
+     * giving a file which does not parse. It is separated by a space instead, which is reported since the exported text
+     * is then not exactly the one which was written.
+     * </p>
+     * <p>
+     * The reverse replacement is deliberately not done on import: a body may legitimately contain the separated form,
+     * and turning it back would corrupt it.
+     * </p>
+     *
+     * @param body
+     *            the body of a comment, a documentation or a textual representation
+     * @return the body, with any block comment terminator separated by a space
+     */
+    private String escapeCommentTerminator(String body) {
+        if (body == null || !body.contains(COMMENT_TERMINATOR)) {
+            return body;
+        }
+        this.reportConsumer.accept(Status.warning(
+                "A comment body contains \"{0}\", which closes a comment. It has been exported as \"{1}\" so the text remains valid.",
+                COMMENT_TERMINATOR, ESCAPED_COMMENT_TERMINATOR));
+        return body.replace(COMMENT_TERMINATOR, ESCAPED_COMMENT_TERMINATOR);
+    }
+
     private void appendLocale(Appender builder, String local) {
         if (!this.isNullOrEmpty(local)) {
             builder.appendSpaceIfNeeded().append("locale").append(" \"").append(local).append("\"");

doc/content/modules/user-manual/pages/release-notes/2026.9.0.adoc

@@ -124,6 +124,10 @@ The affected connections were missing their source and target and were therefore
 Exporting such a connection and importing it back no longer loses which end is which.
 ** Fix the import of `TransitionUsage` using _start_ which now set the source to the `StateUsage` _start_ from the standard library instead of `ActionUsage` _start_ from the standard library.
 
+** Fix the export of a documentation, a comment or a textual representation whose text contains `*/`.
+That sequence closes a comment in the SysML v2 textual notation, so the exported file could no longer be read.
+It is now exported as `* /`, and a warning reports it, since the exported text is then not exactly the one that was written.
+
 == Improvements
 
 * {product} Docker images now support `linux/amd64` and `linux/arm64` and run natively on arm64 machines such as Apple Silicon or AWS Graviton.