Commit 139997d8e for llama.cpp

commit 139997d8e74255f7c7a64759f02e3ac42c2e595c
Author: vaibhavdedhia <vaibhavdedhia@gmail.com>
Date:   Tue Sep 29 11:48:58 2026 +0530

    chat : fix Muse Glimmer ignoring response_format json_schema with --jinja (#29615)

    * chat : fix Muse Glimmer ignoring response_format json_schema with --jinja

    Fixes #29613

    * chat : accept json fences and clean up

    * chat : fix choice parenthesis

    ---------

    Co-authored-by: Alde Rojas <hello@alde.dev>

diff --git a/common/parsers/muse-glimmer.cpp b/common/parsers/muse-glimmer.cpp
index d03bf2d58..784928269 100644
--- a/common/parsers/muse-glimmer.cpp
+++ b/common/parsers/muse-glimmer.cpp
@@ -43,9 +43,10 @@ common_chat_params common_chat_params_init_muse_glimmer(const common_chat_templa

     auto extract_reasoning = inputs.reasoning_format != COMMON_REASONING_FORMAT_NONE;

-    auto has_tools = inputs.tools.is_array() && !inputs.tools.empty();
-    // Constrained grammar whenever tools are offered.
-    auto include_grammar = has_tools && inputs.tool_choice != COMMON_CHAT_TOOL_CHOICE_NONE;
+    auto has_tools           = inputs.tools.is_array() && !inputs.tools.empty();
+    auto has_response_format = !inputs.json_schema.is_null() && inputs.json_schema.is_object();
+    // Constrained grammar whenever tools are offered or a response format is requested.
+    auto include_grammar     = has_response_format || (has_tools && inputs.tool_choice != COMMON_CHAT_TOOL_CHOICE_NONE);

     auto parser = build_chat_peg_parser([&](common_chat_peg_builder & p) {
         auto start = p.rule("start", p.literal("<|start|>assistant"));
@@ -65,6 +66,15 @@ common_chat_params common_chat_params_init_muse_glimmer(const common_chat_templa
         auto final_msg  = p.rule("final", recipient + p.literal("<|message|>") +
                                               p.content(p.until_one_of({ "<|eot|>", "<|eom|>" })));

+        if (has_response_format) {
+            auto response_json   = p.content(p.schema(p.json(), "response-format-schema", inputs.json_schema));
+            auto response_format = p.rule("response-format",
+                recipient + p.literal("<|message|>") +
+                ((p.literal("```json") + p.space() + response_json + p.space() + p.literal("```")) | response_json));
+
+            return p.zero_or_more(start + analysis) + start + response_format;
+        }
+
         if (has_tools && inputs.tool_choice != COMMON_CHAT_TOOL_CHOICE_NONE) {
             auto string_value = p.ac(
                 p.tool_arg_string_value(p.until("</atem:parameter>")) + p.tool_arg_close(p.literal("</atem:parameter>")),
@@ -124,7 +134,7 @@ common_chat_params common_chat_params_init_muse_glimmer(const common_chat_templa
     data.parser = parser.save();

     if (include_grammar) {
-        data.grammar_lazy = inputs.tool_choice != COMMON_CHAT_TOOL_CHOICE_REQUIRED;
+        data.grammar_lazy = !(has_response_format || (has_tools && inputs.tool_choice == COMMON_CHAT_TOOL_CHOICE_REQUIRED));
         data.grammar      = build_grammar([&](const common_grammar_builder & builder) {
             parser.build_grammar(builder, data.grammar_lazy);
         });
diff --git a/tests/test-chat.cpp b/tests/test-chat.cpp
index f2728f7cc..6b8b85616 100644
--- a/tests/test-chat.cpp
+++ b/tests/test-chat.cpp
@@ -1217,6 +1217,16 @@ static void test_peg_parser(common_chat_templates *                      tmpls,
     }
     assert_msg_equals(tc.expect, msg_accum, true);

+    // A response format must be enforced by an eager grammar
+    if (!tc.params.json_schema.empty()) {
+        if (parser.params_.grammar.empty()) {
+            throw std::runtime_error("json_schema is set but no grammar was produced");
+        }
+        if (parser.params_.grammar_lazy) {
+            throw std::runtime_error("json_schema is set but the grammar is lazy");
+        }
+    }
+
     // Test grammar if present in params
     if (!parser.params_.grammar.empty()) {
         auto grammar = build_grammar(parser.params_.grammar);
@@ -6384,6 +6394,22 @@ static void test_template_output_peg_parsers(bool detailed_debug) {
             .expect_content("You invoke it like this:\n" + call_markup)
             .run();

+        // Structured output, straight to the final answer
+        tst.test(" to=user<|message|>" R"({"amount": 123.45, "date": "2025-12-03"})")
+            .reasoning_format(COMMON_REASONING_FORMAT_AUTO)
+            .json_schema(invoice_schema)
+            .expect_content(R"({"amount": 123.45, "date": "2025-12-03"})")
+            .run();
+
+        // Structured output after a reasoning message: reasoning stays free-form
+        tst.test(" to=self<|message|>I need to output the invoice details in JSON<|eom|>"
+                 "<|start|>assistant to=user<|message|>" R"({"amount": 123.45, "date": "2025-12-03"})")
+            .reasoning_format(COMMON_REASONING_FORMAT_AUTO)
+            .json_schema(invoice_schema)
+            .expect_reasoning("I need to output the invoice details in JSON")
+            .expect_content(R"({"amount": 123.45, "date": "2025-12-03"})")
+            .run();
+
         // Tool markup inside the analysis channel is reasoning, not a call
         tst.test(" to=self<|message|>I could use " + call_markup + " here<|eom|>"
                  "<|start|>assistant to=user<|message|>Hello!<|eot|>")