json-schema-to-grammar improvements (+ added to server) (#5978)

* json: fix arrays (disallow `[,1]`)

* json: support tuple types (`[number, string]`)

* json: support additionalProperties (`{[k: string]: [string,number][]}`)

* json: support required / optional properties

* json: add support for pattern

* json: resolve $ref (and support https schema urls)

* json: fix $ref resolution

* join: support union types (mostly for nullable types I think)

* json: support allOf + nested anyOf

* json: support any (`{}` or `{type: object}`)

* json: fix merge

* json: temp fix for escapes

* json: spaces in output and unrestricted output spaces

* json: add typings

* json:fix typo

* Create ts-type-to-grammar.sh

* json: fix _format_literal (json.dumps already escapes quotes)

* json: merge lit sequences and handle negatives

{"type": "string", "pattern": "^({\"question\": \"[^\"]+\", \"response\": \"[^\"]+\"}\\n)+$"}

* json: handle pattern repetitions

* Update json-schema-to-grammar.mjs

* Create regex-to-grammar.py

* json: extract repeated regexp patterns to subrule

* Update json-schema-to-grammar.py

* Update json-schema-to-grammar.py

* Update json-schema-to-grammar.py

* json: handle schema from pydantic Optional fields

* Update json-schema-to-grammar.py

* Update json-schema-to-grammar.py

* Update ts-type-to-grammar.sh

* Update ts-type-to-grammar.sh

* json: simplify nullable fields handling

* json: accept duplicate identical rules

* json: revert space to 1 at most

* json: reuse regexp pattern subrules

* json: handle uuid string format

* json: fix literal escapes

* json: add --allow-fetch

* json: simplify range escapes

* json: support negative ranges in patterns

* Delete commit.txt

* json: custom regex parser, adds dot support & JS-portable

* json: rm trailing spaces

* Update json-schema-to-grammar.mjs

* json: updated server & chat `( cd examples/server && ./deps.sh )`

* json: port fixes from mjs to python

* Update ts-type-to-grammar.sh

* json: support prefixItems alongside array items

* json: add date format + fix uuid

* json: add date, time, date-time formats

* json: preserve order of props from TS defs

* json: port schema converter to C++, wire in ./server

* json: nits

* Update json-schema-to-grammar.cpp

* Update json-schema-to-grammar.cpp

* Update json-schema-to-grammar.cpp

* json: fix mjs implementation + align outputs

* Update json-schema-to-grammar.mjs.hpp

* json: test C++, JS & Python versions

* json: nits + regen deps

* json: cleanup test

* json: revert from c++17 to 11

* json: nit fixes

* json: dirty include for test

* json: fix zig build

* json: pass static command to std::system in tests (fixed temp files)

* json: fix top-level $refs

* json: don't use c++20 designated initializers

* nit

* json: basic support for reserved names `{number:{number:{root:number}}}`

* Revamp test cmake to allow args (WORKING_DIRECTORY needed for JSON test)

* json: re-ran server deps.sh

* json: simplify test

* json: support mix of additional props & required/optional

* json: add tests for some expected failures

* json: fix type=const in c++, add failure expectations for non-str const&enum

* json: test (& simplify output of) empty schema

* json: check parsing in test + fix value & string refs

* json: add server tests for OAI JSON response_format

* json: test/fix top-level anyOf

* json: improve grammar parsing failures

* json: test/fix additional props corner cases

* json: fix string patterns (was missing quotes)

* json: ws nit

* json: fix json handling in server when there's no response_format

* json: catch schema conversion errors in server

* json: don't complain about unknown format type in server if unset

* json: cleaner build of test

* json: create examples/json-schema-pydantic-example.py

* json: fix date pattern

* json: move json.hpp & json-schema-to-grammar.{cpp,h} to common

* json: indent 4 spaces

* json: fix naming of top-level c++ function (+ drop unused one)

* json: avoid using namespace std

* json: fix zig build

* Update server.feature

* json: iostream -> fprintf

* json: space before & refs for consistency

* json: nits

3 files changed, 49 insertions, 0 deletions

diff --git a/examples/server/tests/features/security.feature b/examples/server/tests/features/security.feature
index 1d6aa40e..eb82e7ac 100644
--- a/examples/server/tests/features/security.feature
+++ b/examples/server/tests/features/security.feature
@@ -37,6 +37,22 @@ Feature: Security
       | llama.cpp | no        |
       | hackme    | raised    |
 
+  Scenario Outline: OAI Compatibility (invalid response formats)
+    Given a system prompt test
+    And   a user prompt test
+    And   a response format <response_format>
+    And   a model test
+    And   2 max tokens to predict
+    And   streaming is disabled
+    Given an OAI compatible chat completions request with raised api error
+
+    Examples: Prompts
+      | response_format                                       |
+      | {"type": "sound"}                                     |
+      | {"type": "json_object", "schema": 123}                |
+      | {"type": "json_object", "schema": {"type": 123}}      |
+      | {"type": "json_object", "schema": {"type": "hiccup"}} |
+
 
   Scenario Outline: CORS Options
     Given a user api key llama.cpp
diff --git a/examples/server/tests/features/server.feature b/examples/server/tests/features/server.feature
index 45a988db..a2e0e5b3 100644
--- a/examples/server/tests/features/server.feature
+++ b/examples/server/tests/features/server.feature
@@ -70,6 +70,22 @@ Feature: llama.cpp server
       | codellama70b | You are a coding assistant. | Write the fibonacci function in c++. | 128        | (thanks\|happy\|bird\|Annabyear)+ | -1       | 64          | enabled          |           |
 
 
+  Scenario Outline: OAI Compatibility w/ response format
+    Given a model test
+    And   a system prompt test
+    And   a user prompt test
+    And   a response format <response_format>
+    And   10 max tokens to predict
+    Given an OAI compatible chat completions request with no api error
+    Then  <n_predicted> tokens are predicted matching <re_content>
+
+    Examples: Prompts
+      | response_format                                                     | n_predicted | re_content             |
+      | {"type": "json_object", "schema": {"const": "42"}}                  | 5           | "42"                   |
+      | {"type": "json_object", "schema": {"items": [{"type": "integer"}]}} | 10          | \[ -300 \]             |
+      | {"type": "json_object"}                                             | 10          | \{ " Jacky.            |
+
+
   Scenario: Tokenize / Detokenize
     When tokenizing:
     """
diff --git a/examples/server/tests/features/steps/steps.py b/examples/server/tests/features/steps/steps.py
index 42cdd898..03f55f65 100644
--- a/examples/server/tests/features/steps/steps.py
+++ b/examples/server/tests/features/steps/steps.py
@@ -59,6 +59,7 @@ def step_server_config(context, server_fqdn, server_port):
     context.seed = None
     context.server_seed = None
     context.user_api_key = None
+    context.response_format = None
 
     context.tasks_result = []
     context.concurrent_tasks = []
@@ -269,6 +270,11 @@ def step_max_tokens(context, max_tokens):
     context.n_predict = max_tokens
 
 
+@step('a response format {response_format}')
+def step_response_format(context, response_format):
+    context.response_format = json.loads(response_format)
+
+
 @step('streaming is {enable_streaming}')
 def step_streaming(context, enable_streaming):
     context.enable_streaming = enable_streaming == 'enabled'
@@ -384,6 +390,9 @@ async def step_oai_chat_completions(context, api_error):
                                             enable_streaming=context.enable_streaming
                                             if hasattr(context, 'enable_streaming') else None,
 
+                                            response_format=context.response_format
+                                            if hasattr(context, 'response_format') else None,
+
                                             seed=await completions_seed(context),
 
                                             user_api_key=context.user_api_key
@@ -443,6 +452,8 @@ async def step_oai_chat_completions(context):
                               if hasattr(context, 'n_predict') else None,
                               enable_streaming=context.enable_streaming
                               if hasattr(context, 'enable_streaming') else None,
+                              response_format=context.response_format
+                              if hasattr(context, 'response_format') else None,
                               seed=await completions_seed(context),
                               user_api_key=context.user_api_key
                               if hasattr(context, 'user_api_key') else None)
@@ -463,6 +474,8 @@ async def step_oai_chat_completions(context):
                               if hasattr(context, 'n_predict') else None,
                               enable_streaming=context.enable_streaming
                               if hasattr(context, 'enable_streaming') else None,
+                              response_format=context.response_format
+                              if hasattr(context, 'response_format') else None,
                               seed=context.seed
                               if hasattr(context, 'seed') else
                               context.server_seed
@@ -745,6 +758,7 @@ async def oai_chat_completions(user_prompt,
                                model=None,
                                n_predict=None,
                                enable_streaming=None,
+                               response_format=None,
                                seed=None,
                                user_api_key=None,
                                expect_api_error=None):
@@ -770,6 +784,8 @@ async def oai_chat_completions(user_prompt,
         "stream": enable_streaming,
         "seed": seed
     }
+    if response_format is not None:
+        payload['response_format'] = response_format
     completion_response = {
         'content': '',
         'timings': {
@@ -830,6 +846,7 @@ async def oai_chat_completions(user_prompt,
                 model=model,
                 max_tokens=n_predict,
                 stream=enable_streaming,
+                response_format=payload.get('response_format'),
                 seed=seed
             )
         except openai.error.AuthenticationError as e: