fix: preserve GPT Image 2 auto failover defaults

dto/gpt_image2_routing_profile_test.go

@@ -50,9 +50,288 @@ func TestGPTImage2ProductionProfileValidatesAndRoutesTheCompleteMatrix(t *testin
 			Size:        combination.Size,
 		}), "%s %s %s", combination.Resolution, combination.AspectRatio, combination.Size)
 	}
+	assert.False(t, config.Supports("gpt-image-2", dto.ImageSelectionRequirement{
+		Operation:   dto.ImageOperationGeneration,
+		Resolution:  "2K",
+		AspectRatio: "auto",
+	}))
+}
+
+func TestGPTImage2ProductionProfileAllowsContractAutoTupleWithoutInventingDefaults(t *testing.T) {
+	profile := dto.ImageRoutingProfile{
+		Model:              "gpt-image-2",
+		Protocol:           dto.ImageRoutingProtocolImagesGenerations,
+		UpstreamPath:       "/v1/images/generations",
+		Operations:         []dto.ImageOperation{dto.ImageOperationGeneration},
+		Resolutions:        []string{"1K", "2K"},
+		AspectRatios:       []string{"auto", "1:1"},
+		Sizes:              []string{"auto", "1024x1024", "1440x1440"},
+		DefaultSize:        "auto",
+		MaxOutputImages:    1,
+		VerificationStatus: dto.ImageRoutingVerificationProductionVerified,
+		AllowedCombinations: []dto.ImageRoutingCombination{
+			{Operation: dto.ImageOperationGeneration, Size: "auto"},
+			{Operation: dto.ImageOperationGeneration, Resolution: "1K", AspectRatio: "1:1", Size: "1024x1024"},
+			{Operation: dto.ImageOperationGeneration, Resolution: "2K", AspectRatio: "1:1", Size: "1440x1440"},
+		},
+	}
+	config := &dto.ImageRoutingConfig{
+		Version:  dto.ImageRoutingVersion1,
+		Profiles: []dto.ImageRoutingProfile{profile},
+	}
+
+	require.NoError(t, config.Validate())
+
+	auto, err := profile.ApplyDefaults(dto.ImageSelectionRequirement{
+		Operation: dto.ImageOperationGeneration,
+		Size:      "auto",
+		N:         1,
+	})
+	require.NoError(t, err)
+	assert.Equal(t, "", auto.Resolution)
+	assert.Equal(t, "", auto.AspectRatio)
+	assert.Equal(t, "auto", auto.Size)
+
+	explicitAuto, err := profile.ApplyDefaults(dto.ImageSelectionRequirement{
+		Operation:   dto.ImageOperationGeneration,
+		Resolution:  "1K",
+		AspectRatio: "auto",
+		N:           1,
+	})
+	require.NoError(t, err)
+	assert.Equal(t, "1K", explicitAuto.Resolution)
+	assert.Equal(t, "auto", explicitAuto.AspectRatio)
+	assert.Equal(t, "auto", explicitAuto.Size)
+	assert.False(t, config.Supports("gpt-image-2", dto.ImageSelectionRequirement{
+		Operation:   dto.ImageOperationGeneration,
+		Resolution:  "2K",
+		AspectRatio: "auto",
+		Size:        "auto",
+		N:           1,
+	}))
 	assert.False(t, config.Supports("gpt-image-2", dto.ImageSelectionRequirement{
 		Operation:   dto.ImageOperationGeneration,
 		Resolution:  "4K",
 		AspectRatio: "3:2",
+		N:           1,
 	}))
+
+	negativeCases := []struct {
+		name   string
+		mutate func(*dto.ImageRoutingProfile)
+	}{
+		{
+			name: "another model cannot omit defaults",
+			mutate: func(candidate *dto.ImageRoutingProfile) {
+				candidate.Model = "future-image-model"
+			},
+		},
+		{
+			name: "image editing cannot omit defaults",
+			mutate: func(candidate *dto.ImageRoutingProfile) {
+				candidate.Protocol = dto.ImageRoutingProtocolImagesEdits
+				candidate.UpstreamPath = "/v1/images/edits"
+				candidate.Operations = []dto.ImageOperation{dto.ImageOperationEdit}
+				for index := range candidate.AllowedCombinations {
+					candidate.AllowedCombinations[index].Operation = dto.ImageOperationEdit
+				}
+			},
+		},
+		{
+			name: "mixed operations cannot omit defaults",
+			mutate: func(candidate *dto.ImageRoutingProfile) {
+				candidate.Operations = []dto.ImageOperation{dto.ImageOperationGeneration, dto.ImageOperationEdit}
+			},
+		},
+		{
+			name: "missing auto size default cannot omit defaults",
+			mutate: func(candidate *dto.ImageRoutingProfile) {
+				candidate.DefaultSize = ""
+			},
+		},
+	}
+	for _, testCase := range negativeCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			candidate := profile
+			candidate.Operations = append([]dto.ImageOperation(nil), profile.Operations...)
+			candidate.AllowedCombinations = append(
+				[]dto.ImageRoutingCombination(nil),
+				profile.AllowedCombinations...,
+			)
+			testCase.mutate(&candidate)
+			err := (&dto.ImageRoutingConfig{
+				Version:  dto.ImageRoutingVersion1,
+				Profiles: []dto.ImageRoutingProfile{candidate},
+			}).Validate()
+			require.Error(t, err)
+			assert.ErrorContains(t, err, "default_resolution is required")
+		})
+	}
+
+	t.Run("mixed operations cannot restore the contract auto sentinel with explicit defaults", func(t *testing.T) {
+		candidate := profile
+		candidate.Operations = []dto.ImageOperation{dto.ImageOperationGeneration, dto.ImageOperationEdit}
+		candidate.DefaultResolution = "1K"
+		candidate.DefaultAspectRatio = "auto"
+		candidate.AllowedCombinations = append(
+			append([]dto.ImageRoutingCombination(nil), profile.AllowedCombinations...),
+			dto.ImageRoutingCombination{
+				Operation:   dto.ImageOperationEdit,
+				Resolution:  "1K",
+				AspectRatio: "1:1",
+				Size:        "1024x1024",
+			},
+		)
+		err := (&dto.ImageRoutingConfig{
+			Version:  dto.ImageRoutingVersion1,
+			Profiles: []dto.ImageRoutingProfile{candidate},
+		}).Validate()
+		require.Error(t, err)
+		assert.ErrorContains(t, err, "exact size")
+	})
+
+	t.Run("contract auto sentinel cannot carry output controls", func(t *testing.T) {
+		candidate := profile
+		candidate.DefaultResolution = "1K"
+		candidate.DefaultAspectRatio = "auto"
+		candidate.OutputFormats = []string{"png"}
+		candidate.DefaultOutputFormat = "png"
+		candidate.AllowedCombinations = append(
+			[]dto.ImageRoutingCombination(nil),
+			profile.AllowedCombinations...,
+		)
+		candidate.AllowedCombinations[0].OutputFormat = "png"
+		err := (&dto.ImageRoutingConfig{
+			Version:  dto.ImageRoutingVersion1,
+			Profiles: []dto.ImageRoutingProfile{candidate},
+		}).Validate()
+		require.Error(t, err)
+		assert.ErrorContains(t, err, "exact size")
+	})
+
+	for _, testCase := range []struct {
+		name        string
+		configure   func(*dto.ImageRoutingProfile)
+		requirement dto.ImageSelectionRequirement
+	}{
+		{
+			name: "contract auto sentinel cannot borrow a declared quality",
+			configure: func(candidate *dto.ImageRoutingProfile) {
+				candidate.Qualities = []string{"high"}
+				candidate.DefaultQuality = "high"
+				for index := 1; index < len(candidate.AllowedCombinations); index++ {
+					candidate.AllowedCombinations[index].Quality = "high"
+				}
+			},
+			requirement: dto.ImageSelectionRequirement{
+				Operation: dto.ImageOperationGeneration,
+				Size:      "auto",
+				Quality:   "high",
+				N:         1,
+			},
+		},
+		{
+			name: "contract auto sentinel cannot borrow a declared output format",
+			configure: func(candidate *dto.ImageRoutingProfile) {
+				candidate.OutputFormats = []string{"png"}
+				candidate.DefaultOutputFormat = "png"
+				for index := 1; index < len(candidate.AllowedCombinations); index++ {
+					candidate.AllowedCombinations[index].OutputFormat = "png"
+				}
+			},
+			requirement: dto.ImageSelectionRequirement{
+				Operation:    dto.ImageOperationGeneration,
+				Size:         "auto",
+				OutputFormat: "png",
+				N:            1,
+			},
+		},
+	} {
+		t.Run(testCase.name, func(t *testing.T) {
+			candidate := profile
+			candidate.AllowedCombinations = append(
+				[]dto.ImageRoutingCombination(nil),
+				profile.AllowedCombinations...,
+			)
+			testCase.configure(&candidate)
+			config := &dto.ImageRoutingConfig{
+				Version:  dto.ImageRoutingVersion1,
+				Profiles: []dto.ImageRoutingProfile{candidate},
+			}
+
+			err := config.Validate()
+			require.Error(t, err)
+			assert.ErrorContains(t, err, "default image tuple")
+			assert.False(t, config.Supports("gpt-image-2", testCase.requirement))
+		})
+	}
+
+	for _, testCase := range []struct {
+		name        string
+		configure   func(*dto.ImageRoutingProfile)
+		requirement dto.ImageSelectionRequirement
+	}{
+		{
+			name: "exact auto geometry cannot borrow a declared quality",
+			configure: func(candidate *dto.ImageRoutingProfile) {
+				candidate.Qualities = []string{"high"}
+				candidate.DefaultQuality = "high"
+				for index := 1; index < len(candidate.AllowedCombinations); index++ {
+					candidate.AllowedCombinations[index].Quality = "high"
+				}
+			},
+			requirement: dto.ImageSelectionRequirement{
+				Operation:   dto.ImageOperationGeneration,
+				Resolution:  "1K",
+				AspectRatio: "auto",
+				Size:        "auto",
+				Quality:     "high",
+				N:           1,
+			},
+		},
+		{
+			name: "exact auto geometry cannot borrow a declared output format",
+			configure: func(candidate *dto.ImageRoutingProfile) {
+				candidate.OutputFormats = []string{"png"}
+				candidate.DefaultOutputFormat = "png"
+				for index := 1; index < len(candidate.AllowedCombinations); index++ {
+					candidate.AllowedCombinations[index].OutputFormat = "png"
+				}
+			},
+			requirement: dto.ImageSelectionRequirement{
+				Operation:    dto.ImageOperationGeneration,
+				Resolution:   "1K",
+				AspectRatio:  "auto",
+				Size:         "auto",
+				OutputFormat: "png",
+				N:            1,
+			},
+		},
+	} {
+		t.Run(testCase.name, func(t *testing.T) {
+			candidate := profile
+			candidate.DefaultResolution = "1K"
+			candidate.DefaultAspectRatio = "auto"
+			candidate.AllowedCombinations = append(
+				[]dto.ImageRoutingCombination(nil),
+				profile.AllowedCombinations...,
+			)
+			candidate.AllowedCombinations[0] = dto.ImageRoutingCombination{
+				Operation:   dto.ImageOperationGeneration,
+				Resolution:  "1K",
+				AspectRatio: "auto",
+				Size:        "auto",
+			}
+			testCase.configure(&candidate)
+			config := &dto.ImageRoutingConfig{
+				Version:  dto.ImageRoutingVersion1,
+				Profiles: []dto.ImageRoutingProfile{candidate},
+			}
+
+			err := config.Validate()
+			require.Error(t, err)
+			assert.ErrorContains(t, err, "default image tuple")
+			assert.False(t, config.Supports("gpt-image-2", testCase.requirement))
+		})
+	}
 }