Ruby: add databaseMetadata relation to dbscheme

This is required for overlay support.

config/dbscheme-fragments.json

@@ -11,6 +11,7 @@
     "/*- Diagnostic messages -*/",
     "/*- Diagnostic messages: severity -*/",
     "/*- Source location prefix -*/",
+    "/*- Database metadata -*/",
     "/*- Lines of code -*/",
     "/*- Configuration files with key value pairs -*/",
     "/*- YAML -*/",
@@ -31,4 +32,4 @@
     "/*- Python dbscheme -*/",
     "/*- Empty location -*/"
   ]
-}
+}

ql/extractor/src/generator.rs

@@ -36,5 +36,5 @@ pub fn run(options: Options) -> std::io::Result<()> {
         },
     ];
 
-    generate(languages, options.dbscheme, options.library)
+    generate(languages, options.dbscheme, options.library, false)
 }

ruby/downgrades/dc51d416301df12df5b70fbc4338de6cc1f82bfd/upgrade.properties

@@ -0,0 +1,3 @@
+description: Add databaseMetadata relation
+compatibility: full
+databaseMetadata.rel: delete

ruby/extractor/src/generator.rs

@@ -28,5 +28,5 @@ pub fn run(options: Options) -> std::io::Result<()> {
         },
     ];
 
-    generate(languages, options.dbscheme, options.library)
+    generate(languages, options.dbscheme, options.library, true)
 }

ruby/ql/lib/ruby.dbscheme

@@ -108,6 +108,12 @@ yaml_locations(unique int locatable: @yaml_locatable ref,
 
 @yaml_locatable = @yaml_node | @yaml_error;
 
+/*- Database metadata -*/
+databaseMetadata(
+  string metadataKey: string ref,
+  string value: string ref
+);
+
 /*- Ruby dbscheme -*/
 @ruby_underscore_arg = @ruby_assignment | @ruby_binary | @ruby_conditional | @ruby_operator_assignment | @ruby_range | @ruby_unary | @ruby_underscore_primary
 

ruby/ql/lib/ruby.dbscheme.stats

@@ -21521,6 +21521,42 @@
                 </dep>
             </dependencies>
         </relation>
+        <relation>
+            <name>databaseMetadata</name>
+            <cardinality>1</cardinality>
+            <columnsizes>
+                <e>
+                    <k>metadataKey</k>
+                    <v>1</v>
+                </e>
+                <e>
+                    <k>value</k>
+                    <v>1</v>
+                </e>
+            </columnsizes>
+            <dependencies>
+                <dep>
+                    <src>metadataKey</src>
+                    <trg>value</trg>
+                    <val>
+                        <hist>
+                            <budget>12</budget>
+                            <bs/>
+                        </hist>
+                    </val>
+                </dep>
+                <dep>
+                    <src>value</src>
+                    <trg>metadataKey</trg>
+                    <val>
+                        <hist>
+                            <budget>12</budget>
+                            <bs/>
+                        </hist>
+                    </val>
+                </dep>
+            </dependencies>
+        </relation>
         <relation>
             <name>yaml_aliases</name>
             <cardinality>0</cardinality>

ruby/ql/lib/upgrades/40a6b0a5e81115bd870b3a12a1fe954b06362bb7/upgrade.properties

@@ -0,0 +1,2 @@
+description: Add databaseMetadata relation
+compatibility: full

shared/tree-sitter-extractor/src/generator/mod.rs

@@ -17,6 +17,7 @@ pub fn generate(
     languages: Vec<language::Language>,
     dbscheme_path: PathBuf,
     ql_library_path: PathBuf,
+    add_metadata_relation: bool,
 ) -> std::io::Result<()> {
     let dbscheme_file = File::create(dbscheme_path).map_err(|e| {
         tracing::error!("Failed to create dbscheme file: {}", e);
@@ -32,6 +33,16 @@ pub fn generate(
 
     writeln!(dbscheme_writer, include_str!("prefix.dbscheme"))?;
 
+    // Eventually all languages will have the metadata relation (for overlay support), at which
+    // point this could be moved to prefix.dbscheme.
+    if add_metadata_relation {
+        writeln!(dbscheme_writer, "/*- Database metadata -*/",)?;
+        dbscheme::write(
+            &mut dbscheme_writer,
+            &[dbscheme::Entry::Table(create_database_metadata())],
+        )?;
+    }
+
     let mut ql_writer = LineWriter::new(File::create(ql_library_path)?);
     writeln!(
         ql_writer,
@@ -442,3 +453,26 @@ fn create_token_case<'a>(name: &'a str, token_kinds: Map<&'a str, usize>) -> dbs
         branches,
     }
 }
+
+fn create_database_metadata() -> dbscheme::Table<'static> {
+    dbscheme::Table {
+        name: "databaseMetadata",
+        keysets: None,
+        columns: vec![
+            dbscheme::Column {
+                db_type: dbscheme::DbColumnType::String,
+                name: "metadataKey",
+                unique: false,
+                ql_type: ql::Type::String,
+                ql_type_is_ref: true,
+            },
+            dbscheme::Column {
+                db_type: dbscheme::DbColumnType::String,
+                name: "value",
+                unique: false,
+                ql_type: ql::Type::String,
+                ql_type_is_ref: true,
+            },
+        ],
+    }
+}