Support metaschema validation in validate and test (#22)

Signed-off-by: Juan Cruz Viotti <jv@jviotti.com>

src/command_test.cc

@@ -7,10 +7,10 @@
 #include "command.h"
 #include "utils.h"
 
-// TODO: Add a flag to first validate schema against its metaschema
 auto intelligence::jsonschema::cli::test(
     const std::span<const std::string> &arguments) -> int {
-  const auto options{parse_options(arguments, {"h", "http"})};
+  const auto options{
+      parse_options(arguments, {"h", "http", "m", "metaschema"})};
   bool result{true};
   const auto test_resolver{
       resolver(options, options.contains("h") || options.contains("http"))};
@@ -41,6 +41,19 @@ auto intelligence::jsonschema::cli::test(
       return EXIT_FAILURE;
     }
 
+    if (options.contains("m") || options.contains("metaschema")) {
+      const auto metaschema_result{
+          validate_against_metaschema(schema.value(), test_resolver)};
+      if (metaschema_result) {
+        log_verbose(options)
+            << "The schema is valid with respect to its metaschema\n";
+        ;
+      } else {
+        std::cerr << "The schema is NOT valid with respect to its metaschema\n";
+        return EXIT_FAILURE;
+      }
+    }
+
     const auto schema_template{sourcemeta::jsontoolkit::compile(
         schema.value(), sourcemeta::jsontoolkit::default_schema_walker,
         test_resolver, sourcemeta::jsontoolkit::default_schema_compiler)};

src/command_validate.cc

@@ -9,21 +9,37 @@
 #include "command.h"
 #include "utils.h"
 
-// TODO: Add a flag to first validate schema against its metaschema
 // TODO: Add a flag to emit output using the standard JSON Schema output format
 auto intelligence::jsonschema::cli::validate(
     const std::span<const std::string> &arguments) -> int {
-  const auto options{parse_options(arguments, {"h", "http"})};
+  const auto options{
+      parse_options(arguments, {"h", "http", "m", "metaschema"})};
   CLI_ENSURE(options.at("").size() >= 2,
              "You must pass a schema followed by an instance")
   const auto &schema_path{options.at("").at(0)};
   const auto &instance_path{options.at("").at(1)};
+  const auto custom_resolver{
+      resolver(options, options.contains("h") || options.contains("http"))};
 
   const auto schema{sourcemeta::jsontoolkit::from_file(schema_path)};
 
+  // TODO: If not instance is passed, just validate the schema against its
+  // metaschema?
+  if (options.contains("m") || options.contains("metaschema")) {
+    const auto metaschema_result{
+        validate_against_metaschema(schema, custom_resolver)};
+    if (metaschema_result) {
+      log_verbose(options)
+          << "The schema is valid with respect to its metaschema\n";
+      ;
+    } else {
+      std::cerr << "The schema is NOT valid with respect to its metaschema\n";
+      return EXIT_FAILURE;
+    }
+  }
+
   const auto schema_template{sourcemeta::jsontoolkit::compile(
-      schema, sourcemeta::jsontoolkit::default_schema_walker,
-      resolver(options, options.contains("h") || options.contains("http")),
+      schema, sourcemeta::jsontoolkit::default_schema_walker, custom_resolver,
       sourcemeta::jsontoolkit::default_schema_compiler)};
 
   const auto instance{sourcemeta::jsontoolkit::from_file(instance_path)};

src/main.cc

@@ -20,20 +20,23 @@ Global Options:
 
 Commands:
 
-   validate <schema.json> <instance.json> [--http/-h]
+   validate <schema.json> <instance.json> [--http/-h] [--metaschema/-m]
 
        Validate an instance against a schema, printing error information, if
        any, in a human-readable manner. The `--http/-h` option enables resolving
-       remote schemas over the HTTP protocol.
+       remote schemas over the HTTP protocol. The `--metaschema/-m` option
+       checks that the given schema is valid with respects to its dialect
+       metaschema.
 
-   test [schema.json...] [--http/-h]
+   test [schema.json...] [--http/-h] [--metaschema/-m]
 
        A schema test runner inspired by the official JSON Schema test suite.
        Passing directories as input will run every `.json` file in such
        directory (recursively) as a test. If no argument is passed, run every
        `.json` file in the current working directory (recursively) as a test.
       The `--http/-h` option enables resolving remote schemas over the HTTP
-      protocol.
+      protocol. The `--metaschema/-m` option checks that the given schema is
+      valid with respects to its dialect metaschema.
 
    fmt [schema.json...] [--check/-c]
 

src/utils.cc

@@ -1,4 +1,6 @@
 #include <sourcemeta/hydra/httpclient.h>
+#include <sourcemeta/jsontoolkit/json.h>
+#include <sourcemeta/jsontoolkit/jsonschema.h>
 #include <sourcemeta/jsontoolkit/uri.h>
 
 #include "utils.h"
@@ -204,4 +206,29 @@ auto log_verbose(const std::map<std::string, std::vector<std::string>> &options)
   return null_stream;
 }
 
+auto validate_against_metaschema(
+    const sourcemeta::jsontoolkit::JSON &schema,
+    const sourcemeta::jsontoolkit::SchemaResolver &resolver) -> bool {
+  const std::optional<std::string> dialect{
+      sourcemeta::jsontoolkit::dialect(schema)};
+  if (!dialect.has_value()) {
+    throw std::runtime_error(
+        "Cannot determine the dialect of the input schema");
+  }
+
+  const auto metaschema{resolver(dialect.value()).get()};
+  if (!metaschema.has_value()) {
+    throw sourcemeta::jsontoolkit::SchemaResolutionError(
+        dialect.value(), "Could not resolve metaschema");
+  }
+
+  const auto metaschema_template{sourcemeta::jsontoolkit::compile(
+      metaschema.value(), sourcemeta::jsontoolkit::default_schema_walker,
+      resolver, sourcemeta::jsontoolkit::default_schema_compiler)};
+  return sourcemeta::jsontoolkit::evaluate(
+      metaschema_template, schema,
+      sourcemeta::jsontoolkit::SchemaCompilerEvaluationMode::Fast,
+      pretty_evaluate_callback);
+}
+
 } // namespace intelligence::jsonschema::cli

src/utils.h

@@ -45,6 +45,10 @@ auto resolver(const std::map<std::string, std::vector<std::string>> &options,
 auto log_verbose(const std::map<std::string, std::vector<std::string>> &options)
     -> std::ostream &;
 
+auto validate_against_metaschema(
+    const sourcemeta::jsontoolkit::JSON &schema,
+    const sourcemeta::jsontoolkit::SchemaResolver &resolver) -> bool;
+
 } // namespace intelligence::jsonschema::cli
 
 #endif

test/CMakeLists.txt

@@ -16,6 +16,7 @@ add_jsonschema_test_unix(validate_pass)
 add_jsonschema_test_unix(validate_fail)
 add_jsonschema_test_unix(validate_fail_remote_no_http)
 add_jsonschema_test_unix(validate_non_supported)
+add_jsonschema_test_unix(validate_pass_with_metaschema)
 add_jsonschema_test_unix(bundle_non_remote)
 add_jsonschema_test_unix(bundle_remote_single_schema)
 add_jsonschema_test_unix(bundle_remote_no_http)

test/validate_fail_at_metaschema.sh

@@ -0,0 +1,32 @@
+#!/bin/sh
+
+set -o errexit
+set -o nounset
+
+TMP="$(mktemp -d)"
+clean() { rm -rf "$TMP"; }
+trap clean EXIT
+
+cat << 'EOF' > "$TMP/schema.json"
+{
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "properties": {
+    "foo": true,
+    "bar": 1
+  }
+}
+EOF
+
+cat << 'EOF' > "$TMP/instance.json"
+{ "foo": "bar" }
+EOF
+
+"$1" validate "$TMP/schema.json" "$TMP/instance.json" --metaschema && CODE="$?" || CODE="$?"
+
+if [ "$CODE" = "0" ]
+then
+  echo "FAIL" 1>&2
+  exit 1
+else
+  echo "PASS" 1>&2
+fi

test/validate_pass_with_metaschema.sh

@@ -0,0 +1,25 @@
+#!/bin/sh
+
+set -o errexit
+set -o nounset
+
+TMP="$(mktemp -d)"
+clean() { rm -rf "$TMP"; }
+trap clean EXIT
+
+cat << 'EOF' > "$TMP/schema.json"
+{
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "properties": {
+    "foo": {
+      "type": "string"
+    }
+  }
+}
+EOF
+
+cat << 'EOF' > "$TMP/instance.json"
+{ "foo": "bar" }
+EOF
+
+"$1" validate "$TMP/schema.json" "$TMP/instance.json" --metaschema