fix(middleware): parse OpenAI-spec tool_choice in /v1/chat/completions

core/http/middleware/request.go

@@ -14,7 +14,6 @@ import (
 	"github.com/mudler/LocalAI/core/schema"
 	"github.com/mudler/LocalAI/core/services/galleryop"
 	"github.com/mudler/LocalAI/core/templates"
-	"github.com/mudler/LocalAI/pkg/functions"
 	"github.com/mudler/LocalAI/pkg/model"
 	"github.com/mudler/LocalAI/pkg/utils"
 	"github.com/mudler/xlog"
@@ -241,6 +240,28 @@ func (re *RequestExtractor) SetOpenAIRequest(c echo.Context) error {
 	return nil
 }
 
+// extractToolChoiceFunctionName parses a tool_choice map and returns the
+// specific function name. Accepts both the OpenAI-spec nested shape
+// ({type:function, function:{name:...}}) and the legacy/Anthropic-compat
+// flat shape ({type:function, name:...}); the nested form wins when both
+// are present. Returns "" for malformed input or when the shape names a
+// mode rather than a specific tool.
+func extractToolChoiceFunctionName(m map[string]any) string {
+	tcType, ok := m["type"].(string)
+	if !ok || tcType != "function" {
+		return ""
+	}
+	if fn, ok := m["function"].(map[string]any); ok {
+		if n, ok := fn["name"].(string); ok && n != "" {
+			return n
+		}
+	}
+	if n, ok := m["name"].(string); ok {
+		return n
+	}
+	return ""
+}
+
 func mergeOpenAIRequestAndModelConfig(config *config.ModelConfig, input *schema.OpenAIRequest) error {
 	if input.Echo {
 		config.Echo = input.Echo
@@ -320,17 +341,55 @@ func mergeOpenAIRequestAndModelConfig(config *config.ModelConfig, input *schema.
 	}
 
 	if input.ToolsChoice != nil {
-		var toolChoice functions.Tool
-
+		// OpenAI tool_choice has three valid shapes plus one tolerated
+		// non-spec form seen in the wild:
+		//
+		//   1. string mode:    "auto" | "none" | "required"
+		//   2. specific tool:  {"type":"function", "function":{"name":"..."}}  (current spec)
+		//   3. legacy:         {"type":"function", "name":"..."}                (older / Anthropic-compat)
+		//   4. double-encoded: "{\"type\":\"function\", ...}"                   (some clients serialize the object)
+		//
+		// The pre-#9559 code unmarshalled the string case through
+		// json.Unmarshal([]byte(content), &functions.Tool{}), which:
+		//   - failed for plain string modes (so "required" / "none" were
+		//     silently ignored and tools stayed enabled regardless), but
+		//   - happened to handle shape 4 by accident.
+		// It also could not parse shape 3 because functions.Tool has no
+		// flat top-level Name field.
+		//
+		// Mirror the parsing pattern from MergeOpenResponsesConfig (#9509),
+		// route results through the existing input.FunctionCall string/map
+		// dispatch downstream (see the switch on input.FunctionCall in this
+		// same function), and preserve the shape-4 fallback so non-spec
+		// clients don't silently break. Tracked in #9508; sibling fix in #9526.
 		switch content := input.ToolsChoice.(type) {
 		case string:
-			_ = json.Unmarshal([]byte(content), &toolChoice)
+			// "auto" is the default and needs no override. "none" and "required"
+			// both reach SetFunctionCallString via the input.FunctionCall string
+			// branch below; ShouldUseFunctions() then returns false for "none"
+			// (tools disabled) and true for "required" (mode engaged).
+			//
+			// If the string looks like a JSON object, try shape 4 first: parse
+			// it as a tool_choice map and use the resulting name. Falling back
+			// to mode-string handling when the parse yields no usable name keeps
+			// genuinely-malformed input from accidentally engaging a mode.
+			if content == "" || content == "auto" {
+				break
+			}
+			if strings.HasPrefix(strings.TrimSpace(content), "{") {
+				var nested map[string]any
+				if err := json.Unmarshal([]byte(content), &nested); err == nil {
+					if name := extractToolChoiceFunctionName(nested); name != "" {
+						input.FunctionCall = map[string]any{"name": name}
+						break
+					}
+				}
+			}
+			input.FunctionCall = content
 		case map[string]any:
-			dat, _ := json.Marshal(content)
-			_ = json.Unmarshal(dat, &toolChoice)
-		}
-		input.FunctionCall = map[string]any{
-			"name": toolChoice.Function.Name,
+			if name := extractToolChoiceFunctionName(content); name != "" {
+				input.FunctionCall = map[string]any{"name": name}
+			}
 		}
 	}
 

core/http/middleware/request_test.go

@@ -306,3 +306,248 @@ var _ = Describe("MergeOpenResponsesConfig tool_choice parsing", func() {
 		})
 	})
 })
+
+// ---------------------------------------------------------------------------
+// SetModelAndConfig + SetOpenAIRequest - /v1/chat/completions tool_choice parsing
+// ---------------------------------------------------------------------------
+//
+// Parallel to the MergeOpenResponsesConfig specs above, but for the chat
+// completions path. The parsing block lives in mergeOpenAIRequestAndModelConfig
+// (called from SetOpenAIRequest), so these tests drive the full middleware
+// chain the way the production /v1/chat/completions route does.
+//
+// What we assert per shape:
+//   - "required"                                  -> ShouldUseFunctions=true,  no specific name
+//   - "none"                                      -> ShouldUseFunctions=false (tools disabled)
+//   - "auto"                                      -> ShouldUseFunctions=true,  no specific name
+//   - {type:function, function:{name:"X"}} (spec) -> ShouldCallSpecificFunction=true, FunctionToCall="X"
+//   - {type:function, name:"X"}        (legacy)   -> ShouldCallSpecificFunction=true, FunctionToCall="X"
+//   - nested+flat both present                    -> nested wins
+//   - malformed (no type / no name)               -> no-op
+var _ = Describe("SetModelAndConfig tool_choice parsing (chat completions)", func() {
+	var (
+		app            *echo.Echo
+		modelDir       string
+		capturedConfig *config.ModelConfig
+	)
+
+	BeforeEach(func() {
+		var err error
+		modelDir, err = os.MkdirTemp("", "localai-test-models-*")
+		Expect(err).ToNot(HaveOccurred())
+
+		cfgContent := []byte("name: test-model\nbackend: llama-cpp\n")
+		Expect(os.WriteFile(filepath.Join(modelDir, "test-model.yaml"), cfgContent, 0644)).To(Succeed())
+
+		ss := &system.SystemState{
+			Model: system.Model{ModelsPath: modelDir},
+		}
+		appConfig := config.NewApplicationConfig()
+		appConfig.SystemState = ss
+
+		mcl := config.NewModelConfigLoader(modelDir)
+		ml := model.NewModelLoader(ss)
+		re := NewRequestExtractor(mcl, ml, appConfig)
+
+		capturedConfig = nil
+		app = echo.New()
+		app.POST("/v1/chat/completions",
+			func(c echo.Context) error {
+				if cfg, ok := c.Get(CONTEXT_LOCALS_KEY_MODEL_CONFIG).(*config.ModelConfig); ok {
+					capturedConfig = cfg
+				}
+				return c.String(http.StatusOK, "ok")
+			},
+			re.SetModelAndConfig(func() schema.LocalAIRequest { return new(schema.OpenAIRequest) }),
+			func(next echo.HandlerFunc) echo.HandlerFunc {
+				return func(c echo.Context) error {
+					if err := re.SetOpenAIRequest(c); err != nil {
+						return err
+					}
+					return next(c)
+				}
+			},
+		)
+	})
+
+	AfterEach(func() {
+		_ = os.RemoveAll(modelDir)
+	})
+
+	// chatReq wraps a tool_choice JSON fragment in a minimal valid chat-completions
+	// payload. The tools array is non-empty so downstream code paths that gate on
+	// len(input.Functions) see something to work with.
+	chatReq := func(toolChoiceJSON string) string {
+		return `{"model":"test-model",` +
+			`"messages":[{"role":"user","content":"hi"}],` +
+			`"tools":[{"type":"function","function":{"name":"get_weather"}}],` +
+			`"tool_choice":` + toolChoiceJSON + `}`
+	}
+
+	Context("string tool_choice", func() {
+		It("engages mode for tool_choice=\"required\"", func() {
+			rec := postJSON(app, "/v1/chat/completions", chatReq(`"required"`))
+
+			Expect(rec.Code).To(Equal(http.StatusOK))
+			Expect(capturedConfig).ToNot(BeNil())
+			Expect(capturedConfig.ShouldCallSpecificFunction()).To(BeFalse())
+			Expect(capturedConfig.ShouldUseFunctions()).To(BeTrue())
+		})
+
+		It("disables tools for tool_choice=\"none\"", func() {
+			// Before #9559 this was a silent no-op (json.Unmarshal of "none"
+			// into functions.Tool failed); now "none" is honored per OpenAI spec.
+			rec := postJSON(app, "/v1/chat/completions", chatReq(`"none"`))
+
+			Expect(rec.Code).To(Equal(http.StatusOK))
+			Expect(capturedConfig).ToNot(BeNil())
+			Expect(capturedConfig.ShouldUseFunctions()).To(BeFalse())
+			Expect(capturedConfig.ShouldCallSpecificFunction()).To(BeFalse())
+		})
+
+		It("leaves config untouched for tool_choice=\"auto\"", func() {
+			rec := postJSON(app, "/v1/chat/completions", chatReq(`"auto"`))
+
+			Expect(rec.Code).To(Equal(http.StatusOK))
+			Expect(capturedConfig).ToNot(BeNil())
+			Expect(capturedConfig.ShouldCallSpecificFunction()).To(BeFalse())
+			// "auto" is the default: tools available, model decides.
+			Expect(capturedConfig.ShouldUseFunctions()).To(BeTrue())
+			Expect(capturedConfig.FunctionToCall()).To(Equal(""))
+		})
+	})
+
+	Context("specific-function tool_choice (OpenAI spec shape)", func() {
+		It("parses {type:function, function:{name:...}} and forces the named function", func() {
+			rec := postJSON(app, "/v1/chat/completions",
+				chatReq(`{"type":"function","function":{"name":"get_weather"}}`))
+
+			Expect(rec.Code).To(Equal(http.StatusOK))
+			Expect(capturedConfig).ToNot(BeNil())
+			// Key invariant: a correctly-formed OpenAI tool_choice must engage
+			// grammar-based forcing via SetFunctionCallNameString.
+			Expect(capturedConfig.ShouldCallSpecificFunction()).To(BeTrue())
+			Expect(capturedConfig.FunctionToCall()).To(Equal("get_weather"))
+		})
+
+		It("prefers the nested function.name over a stray top-level name", func() {
+			rec := postJSON(app, "/v1/chat/completions",
+				chatReq(`{"type":"function","function":{"name":"correct_name"},"name":"legacy_name"}`))
+
+			Expect(rec.Code).To(Equal(http.StatusOK))
+			Expect(capturedConfig).ToNot(BeNil())
+			Expect(capturedConfig.FunctionToCall()).To(Equal("correct_name"))
+		})
+	})
+
+	Context("specific-function tool_choice (legacy Anthropic-compat shape)", func() {
+		It("parses {type:function, name:...} and forces the named function", func() {
+			rec := postJSON(app, "/v1/chat/completions",
+				chatReq(`{"type":"function","name":"get_weather"}`))
+
+			Expect(rec.Code).To(Equal(http.StatusOK))
+			Expect(capturedConfig).ToNot(BeNil())
+			Expect(capturedConfig.ShouldCallSpecificFunction()).To(BeTrue())
+			Expect(capturedConfig.FunctionToCall()).To(Equal("get_weather"))
+		})
+	})
+
+	// Some non-spec clients send the object form serialized as a JSON string.
+	// The pre-#9559 code accepted that by accident; this Context locks in
+	// continued tolerance so those clients do not silently regress.
+	Context("double-encoded tool_choice (JSON string of an object, non-spec)", func() {
+		It("parses a serialized OpenAI-spec nested object", func() {
+			// tool_choice value is itself a JSON-encoded string containing the
+			// object form. Use json.Marshal of the inner blob so the escapes
+			// are correct regardless of the test reader.
+			inner := `{"type":"function","function":{"name":"get_weather"}}`
+			encoded, err := json.Marshal(inner)
+			Expect(err).ToNot(HaveOccurred())
+			rec := postJSON(app, "/v1/chat/completions", chatReq(string(encoded)))
+
+			Expect(rec.Code).To(Equal(http.StatusOK))
+			Expect(capturedConfig).ToNot(BeNil())
+			Expect(capturedConfig.ShouldCallSpecificFunction()).To(BeTrue())
+			Expect(capturedConfig.FunctionToCall()).To(Equal("get_weather"))
+		})
+
+		It("parses a serialized legacy/Anthropic flat object", func() {
+			inner := `{"type":"function","name":"get_weather"}`
+			encoded, err := json.Marshal(inner)
+			Expect(err).ToNot(HaveOccurred())
+			rec := postJSON(app, "/v1/chat/completions", chatReq(string(encoded)))
+
+			Expect(rec.Code).To(Equal(http.StatusOK))
+			Expect(capturedConfig).ToNot(BeNil())
+			Expect(capturedConfig.ShouldCallSpecificFunction()).To(BeTrue())
+			Expect(capturedConfig.FunctionToCall()).To(Equal("get_weather"))
+		})
+
+		It("falls back to mode-string handling when the JSON string parses but has no usable name", func() {
+			// A JSON-string that decodes to a map without a function name
+			// should not engage specific-function forcing. We expect it to
+			// fall through to the mode-string path; the resulting mode is
+			// the raw blob (nonsense), but ShouldCallSpecificFunction stays
+			// false - the invariant that matters.
+			inner := `{"type":"function"}`
+			encoded, err := json.Marshal(inner)
+			Expect(err).ToNot(HaveOccurred())
+			rec := postJSON(app, "/v1/chat/completions", chatReq(string(encoded)))
+
+			Expect(rec.Code).To(Equal(http.StatusOK))
+			Expect(capturedConfig).ToNot(BeNil())
+			Expect(capturedConfig.ShouldCallSpecificFunction()).To(BeFalse())
+		})
+	})
+
+	Context("malformed tool_choice", func() {
+		It("is a no-op when type is missing", func() {
+			rec := postJSON(app, "/v1/chat/completions",
+				chatReq(`{"function":{"name":"get_weather"}}`))
+
+			Expect(rec.Code).To(Equal(http.StatusOK))
+			Expect(capturedConfig).ToNot(BeNil())
+			Expect(capturedConfig.ShouldCallSpecificFunction()).To(BeFalse())
+		})
+
+		It("is a no-op when type is not \"function\"", func() {
+			rec := postJSON(app, "/v1/chat/completions",
+				chatReq(`{"type":"object","function":{"name":"get_weather"}}`))
+
+			Expect(rec.Code).To(Equal(http.StatusOK))
+			Expect(capturedConfig).ToNot(BeNil())
+			Expect(capturedConfig.ShouldCallSpecificFunction()).To(BeFalse())
+		})
+
+		It("is a no-op when name is missing from both shapes", func() {
+			rec := postJSON(app, "/v1/chat/completions",
+				chatReq(`{"type":"function","function":{}}`))
+
+			Expect(rec.Code).To(Equal(http.StatusOK))
+			Expect(capturedConfig).ToNot(BeNil())
+			Expect(capturedConfig.ShouldCallSpecificFunction()).To(BeFalse())
+			Expect(capturedConfig.FunctionToCall()).To(Equal(""))
+		})
+
+		It("is a no-op when name is empty string", func() {
+			rec := postJSON(app, "/v1/chat/completions",
+				chatReq(`{"type":"function","function":{"name":""}}`))
+
+			Expect(rec.Code).To(Equal(http.StatusOK))
+			Expect(capturedConfig).ToNot(BeNil())
+			Expect(capturedConfig.ShouldCallSpecificFunction()).To(BeFalse())
+		})
+	})
+
+	Context("nil tool_choice", func() {
+		It("is a no-op", func() {
+			rec := postJSON(app, "/v1/chat/completions",
+				`{"model":"test-model","messages":[{"role":"user","content":"hi"}]}`)
+
+			Expect(rec.Code).To(Equal(http.StatusOK))
+			Expect(capturedConfig).ToNot(BeNil())
+			Expect(capturedConfig.ShouldCallSpecificFunction()).To(BeFalse())
+			Expect(capturedConfig.FunctionToCall()).To(Equal(""))
+		})
+	})
+})