fix(asciidoc): escape AsciiDoc table cell separator (|) in generated docs (OpenAPITools#24184)

Regex alternation patterns like `^([0-9A-Z]{3})|([0-9A-Z]{5})$` render an
unescaped `|` into the AsciiDoc `|===` model/parameter tables, which
AsciiDoc parses as a new cell delimiter and breaks the table layout
(OpenAPITools#24119). The same issue applies to any free-form value placed in a
table cell (description, default, enum values), not just pattern.

Add a reusable Mustache lambda (tablecellcontent) that escapes an
unescaped `|` as `\|` when rendering table-cell content in
model.mustache and param.mustache, replacing the earlier
pattern-only fix in toRegularExpression(). The escape is idempotent
via a negative lookbehind, so a pattern that already contains a
backslash-escaped pipe isn't double-escaped.

Fixes OpenAPITools#24119

Author: karunsehwag

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AsciidocDocumentationCodegen.java

@@ -150,6 +150,27 @@ public void execute(final Template.Fragment frag, final Writer out) throws IOExc
         }
     }
 
+    /**
+     * Lambda escaping AsciiDoc table cell separators ("|") in rendered content, so
+     * that free-form values (descriptions, defaults, patterns, enum values, ...)
+     * cannot break the layout of the table they are placed in. Use:
+     *
+     * <pre>
+     * {{#tablecellcontent}}{{description}}{{/tablecellcontent}}
+     * </pre>
+     */
+    public static class TableCellContentLambda implements Mustache.Lambda {
+        // Only escape a "|" that isn't already escaped, so values that legitimately
+        // contain a backslash-escaped pipe (e.g. a regex pattern using "\|" to match
+        // a literal pipe character) aren't mangled with a redundant backslash.
+        private static final java.util.regex.Pattern UNESCAPED_PIPE = java.util.regex.Pattern.compile("(?<!\\\\)\\|");
+
+        @Override
+        public void execute(final Template.Fragment frag, final Writer out) throws IOException {
+            out.write(UNESCAPED_PIPE.matcher(frag.execute()).replaceAll("\\\\|"));
+        }
+    }
+
     protected String invokerPackage = "org.openapitools.client";
     protected String groupId = "org.openapitools";
     protected String artifactId = "openapi-client";
@@ -275,6 +296,7 @@ public AsciidocDocumentationCodegen() {
         languageSpecificPrimitives = new HashSet<>();
         importMapping = new HashMap<>();
 
+        additionalProperties.put("tablecellcontent", new TableCellContentLambda());
     }
 
     @Override

modules/openapi-generator/src/main/resources/asciidoc-documentation/model.mustache

@@ -17,12 +17,12 @@
 | Field Name| Required| Nullable | Type| Description | Format
 
 {{#vars}}
-| {{baseName}}
+| {{#tablecellcontent}}{{baseName}}{{/tablecellcontent}}
 | {{#required}}X{{/required}}
 | {{#isNullable}}X{{/isNullable}}
 | {{#isModel}}<<{{ dataType }}>>{{/isModel}} {{^container}}{{^allowableValues}} {{^isModel}}{{ dataType }}{{/isModel}}{{/allowableValues}}{{#allowableValues}}{{^allowableValues.empty}}<<{{ dataType }}>>{{/allowableValues.empty}}{{/allowableValues}} {{/container}} {{#isContainer}} of <<{{complexType}}>>{{/isContainer}}
-| {{description}}
-| {{{dataFormat}}} {{#isEnum}}_Enum:_ {{#_enum}}{{this}}, {{/_enum}}{{/isEnum}} {{^isEnum}}{{^container}}{{^allowableValues.empty}} {{#allowableValues.values}}{{this}}, {{/allowableValues.values}} {{/allowableValues.empty}}{{/container}}{{/isEnum}}
+| {{#tablecellcontent}}{{description}}{{/tablecellcontent}}
+| {{#tablecellcontent}}{{{dataFormat}}} {{#isEnum}}_Enum:_ {{#_enum}}{{this}}, {{/_enum}}{{/isEnum}} {{^isEnum}}{{^container}}{{^allowableValues.empty}} {{#allowableValues.values}}{{this}}, {{/allowableValues.values}} {{/allowableValues.empty}}{{/container}}{{/isEnum}}{{/tablecellcontent}}
 
 {{/vars}}
 |===
@@ -36,7 +36,7 @@
 | Enum Values
 
 {{#allowableValues.values}}
-| {{this}}
+| {{#tablecellcontent}}{{this}}{{/tablecellcontent}}
 {{/allowableValues.values}}
 
 |===

modules/openapi-generator/src/main/resources/asciidoc-documentation/param.mustache

@@ -1,5 +1,5 @@
-| {{baseName}}
-| {{description}} {{#baseType}}<<{{.}}>>{{/baseType}}
+| {{#tablecellcontent}}{{baseName}}{{/tablecellcontent}}
+| {{#tablecellcontent}}{{description}}{{/tablecellcontent}} {{#baseType}}<<{{.}}>>{{/baseType}}
 | {{^required}}-{{/required}}{{#required}}X{{/required}}
-| {{defaultValue}}
-| {{{pattern}}}
+| {{#tablecellcontent}}{{defaultValue}}{{/tablecellcontent}}
+| {{#tablecellcontent}}{{{pattern}}}{{/tablecellcontent}}

modules/openapi-generator/src/test/java/org/openapitools/codegen/asciidoc/AsciidocGeneratorTest.java

@@ -27,6 +27,40 @@ public class AsciidocGeneratorTest {
 
     private final Logger LOGGER = LoggerFactory.getLogger(AsciidocGeneratorTest.class);
 
+    @Test
+    public void testPipeInPatternIsEscapedInGeneratedTables() throws Exception {
+        File output = Files.createTempDirectory("test").toFile();
+
+        final CodegenConfigurator configurator = new CodegenConfigurator().setGeneratorName("asciidoc")
+                .setInputSpec("src/test/resources/3_0/issue24119-asciidoc-table-cell-pipe.yaml")
+                .setOutputDir(output.getAbsolutePath());
+
+        DefaultGenerator generator = new DefaultGenerator();
+        generator.setGenerateMetadata(false);
+        List<File> generatedFiles = generator.opts(configurator.toClientOptInput()).generate();
+        TestUtils.ensureContainsFile(generatedFiles, output, "index.adoc");
+
+        String markupContent = FileUtils.readFileToString(
+                new File(output, "index.adoc"), StandardCharsets.UTF_8);
+
+        Assert.assertFalse(markupContent.contains("/^([0-9A-Z]{3})|([0-9A-Z]{5})$/"),
+                "unescaped pipe should not appear in generated table cell: " + markupContent);
+        Assert.assertTrue(markupContent.contains("/^([0-9A-Z]{3})\\|([0-9A-Z]{5})$/"),
+                "expected escaped pipe in pattern column: " + markupContent);
+
+        Assert.assertFalse(markupContent.contains("Accepts AAA|BBBBB"),
+                "unescaped pipe should not appear in generated description cell: " + markupContent);
+        Assert.assertTrue(markupContent.contains("Accepts AAA\\|BBBBB"),
+                "expected escaped pipe in description column: " + markupContent);
+
+        // a pipe that is already backslash-escaped in the source pattern must not be
+        // escaped a second time.
+        Assert.assertTrue(markupContent.contains("/^A\\|B$/"),
+                "expected already-escaped pipe to remain single-escaped: " + markupContent);
+        Assert.assertFalse(markupContent.contains("/^A\\\\|B$/"),
+                "already-escaped pipe should not be double-escaped: " + markupContent);
+    }
+
     @Test
     public void testPingSpecTitle() throws Exception {
         final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/3_0/ping.yaml");

modules/openapi-generator/src/test/resources/3_0/issue24119-asciidoc-table-cell-pipe.yaml

@@ -0,0 +1,34 @@
+openapi: 3.0.3
+info:
+  title: asciidoc pipe escaping test
+  version: '1.0'
+paths:
+  /things:
+    get:
+      operationId: getThing
+      parameters:
+        - name: code
+          in: query
+          required: false
+          description: "Accepts AAA|BBBBB"
+          schema:
+            type: string
+            pattern: "^([0-9A-Z]{3})|([0-9A-Z]{5})$"
+        - name: preEscapedCode
+          in: query
+          required: false
+          schema:
+            type: string
+            pattern: "^A\\|B$"
+      responses:
+        '200':
+          description: OK
+components:
+  schemas:
+    Thing:
+      type: object
+      properties:
+        code:
+          type: string
+          description: "Accepts AAA|BBBBB"
+          pattern: "^([0-9A-Z]{3})|([0-9A-Z]{5})$"