Serve OpenAPI 3.0 spec at /openapi.v1.json

.editorconfig

@@ -18,7 +18,7 @@ indent_style = tab
 [templates/custom/*.tmpl]
 insert_final_newline = false
 
-[templates/swagger/v1_json.tmpl]
+[templates/swagger/*_json.tmpl]
 indent_style = space
 insert_final_newline = false
 

Makefile

@@ -151,6 +151,7 @@ ESLINT_CONCURRENCY ?= 2
 SWAGGER_SPEC := templates/swagger/v1_json.tmpl
 SWAGGER_SPEC_INPUT := templates/swagger/v1_input.json
 SWAGGER_EXCLUDE := code.gitea.io/sdk
+OPENAPI3_SPEC := templates/swagger/v1_openapi3_json.tmpl
 
 TEST_MYSQL_HOST ?= mysql:3306
 TEST_MYSQL_DBNAME ?= testgitea
@@ -233,7 +234,7 @@ TAGS_PREREQ := $(TAGS_EVIDENCE)
 endif
 
 .PHONY: generate-swagger
-generate-swagger: $(SWAGGER_SPEC) ## generate the swagger spec from code comments
+generate-swagger: $(SWAGGER_SPEC) $(OPENAPI3_SPEC) ## generate the swagger spec from code comments
 
 $(SWAGGER_SPEC): $(GO_SOURCES) $(SWAGGER_SPEC_INPUT)
 	$(GO) run $(SWAGGER_PACKAGE) generate spec --exclude "$(SWAGGER_EXCLUDE)" --input "$(SWAGGER_SPEC_INPUT)" --output './$(SWAGGER_SPEC)'
@@ -255,14 +256,29 @@ swagger-validate: ## check if the swagger spec is valid
 	$(GO) run $(SWAGGER_PACKAGE) validate './$(SWAGGER_SPEC)'
 	@$(SED_INPLACE) -E -e 's|"basePath":( *)"/(.*)"|"basePath":\1"\2"|g' './$(SWAGGER_SPEC)' # remove the prefix slash from basePath
 
+.PHONY: generate-openapi3
+generate-openapi3: $(OPENAPI3_SPEC) ## generate the OpenAPI 3.0 spec from the Swagger 2.0 spec
+
+$(OPENAPI3_SPEC): $(SWAGGER_SPEC) build/generate-openapi.go $(wildcard build/openapi3gen/*.go)
+	$(GO) run build/generate-openapi.go
+
+.PHONY: openapi3-check
+openapi3-check: generate-openapi3
+	@diff=$$(git diff --color=always '$(OPENAPI3_SPEC)'); \
+	if [ -n "$$diff" ]; then \
+		echo "Please run 'make generate-openapi3' and commit the result:"; \
+		printf "%s" "$${diff}"; \
+		exit 1; \
+	fi
+
 .PHONY: checks
 checks: checks-frontend checks-backend ## run various consistency checks
 
 .PHONY: checks-frontend
 checks-frontend: lockfile-check svg-check ## check frontend files
 
 .PHONY: checks-backend
-checks-backend: tidy-check swagger-check fmt-check swagger-validate security-check ## check backend files
+checks-backend: tidy-check swagger-check openapi3-check fmt-check swagger-validate security-check ## check backend files
 
 .PHONY: lint
 lint: lint-frontend lint-backend lint-spell ## lint everything

build/generate-openapi.go

@@ -0,0 +1,97 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+// generate-openapi converts Gitea's Swagger 2.0 spec into an OpenAPI 3.0 spec.
+//
+// Gitea generates a Swagger 2.0 spec from code annotations (make generate-swagger).
+// This tool converts it to OAS3 so that SDK generators and tools that require
+// OAS3 (e.g. progenitor for Rust) can consume it directly. The conversion also
+// deduplicates inline enum definitions into named schema components, producing
+// cleaner SDK output with proper enum types instead of anonymous strings.
+//
+// Run: go run build/generate-openapi.go
+// Output: templates/swagger/v1_openapi3_json.tmpl
+
+//go:build ignore
+
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"os"
+	"regexp"
+	"sort"
+	"strings"
+
+	"code.gitea.io/gitea/build/openapi3gen"
+
+	"github.com/getkin/kin-openapi/openapi3"
+)
+
+const (
+	swaggerSpecPath = "templates/swagger/v1_json.tmpl"
+	openapi3OutPath = "templates/swagger/v1_openapi3_json.tmpl"
+
+	appSubUrlVar = "{{.SwaggerAppSubUrl}}"
+	appVerVar    = "{{.SwaggerAppVer}}"
+
+	appSubUrlPlaceholder = "GITEA_APP_SUB_URL_PLACEHOLDER"
+	appVerPlaceholder    = "0.0.0-gitea-placeholder"
+)
+
+var (
+	appSubUrlRe = regexp.MustCompile(regexp.QuoteMeta(appSubUrlVar))
+	appVerRe    = regexp.MustCompile(regexp.QuoteMeta(appVerVar))
+
+	enumScanDirs = []string{
+		"modules/structs",
+		"modules/commitstatus",
+	}
+)
+
+func main() {
+	astEnumMap, err := openapi3gen.ScanSwaggerEnumTypes(enumScanDirs)
+	if err != nil {
+		log.Fatalf("scanning swagger:enum annotations: %v", err)
+	}
+	names := make([]string, 0, len(astEnumMap))
+	for _, n := range astEnumMap {
+		names = append(names, n)
+	}
+	sort.Strings(names)
+	fmt.Fprintf(os.Stderr, "discovered %d swagger:enum types: %s\n", len(names), strings.Join(names, ", "))
+
+	data, err := os.ReadFile(swaggerSpecPath)
+	if err != nil {
+		log.Fatalf("reading swagger spec: %v", err)
+	}
+
+	cleaned := appSubUrlRe.ReplaceAll(data, []byte(appSubUrlPlaceholder))
+	cleaned = appVerRe.ReplaceAll(cleaned, []byte(appVerPlaceholder))
+
+	oas3, err := openapi3gen.Convert(cleaned, astEnumMap)
+	if err != nil {
+		log.Fatalf("converting to openapi 3.0: %v", err)
+	}
+
+	oas3.Servers = openapi3.Servers{
+		{URL: appSubUrlPlaceholder + "/api/v1"},
+	}
+
+	out, err := json.MarshalIndent(oas3, "", "  ")
+	if err != nil {
+		log.Fatalf("marshaling openapi 3.0: %v", err)
+	}
+
+	result := strings.ReplaceAll(string(out), appSubUrlPlaceholder, appSubUrlVar)
+	result = strings.ReplaceAll(result, appVerPlaceholder, appVerVar)
+	result = strings.TrimSpace(result)
+
+	if err := os.WriteFile(openapi3OutPath, []byte(result), 0o644); err != nil {
+		log.Fatalf("writing openapi 3.0 spec: %v", err)
+	}
+
+	fmt.Printf("Generated %s\n", openapi3OutPath)
+}