feat: add schema versioning support

cmd/plugin/main.go

@@ -11,6 +11,8 @@ import (
 	plugin "github.com/SemRels/hook-gitplugin/internal/plugin"
 )
 
+const pluginSchemaVersion = 1
+
 type gitPlugin interface {
 	Validate() error
 	CommitFiles(context.Context, string, string) error
@@ -24,6 +26,7 @@ var (
 )
 
 func run(ctx context.Context, getenv func(string) string, stderr io.Writer) int {
+	fmt.Fprintf(stderr, "plugin_schema_version=%d\n", pluginSchemaVersion)
 	tagName := firstNonEmpty(getenv("SEMREL_PLUGIN_TAG_NAME"), getenv("SEMREL_TAG_NAME"), getenv("SEMREL_VERSION"), getenv("SEMREL_NEXT_VERSION"))
 	versionSource := firstNonEmpty(getenv("SEMREL_VERSION"), getenv("SEMREL_TAG_NAME"), getenv("SEMREL_NEXT_VERSION"), tagName)
 	if tagName == "" || versionSource == "" {

cmd/plugin/main_test.go

@@ -61,7 +61,7 @@ func TestRunSuccess(t *testing.T) {
 		"SEMREL_PLUGIN_SIGN_TAG":      "true",
 		"SEMREL_PLUGIN_SIGNED_OFF_BY": "true",
 	}), &stderr)
-	if code != 0 || stderr.Len() != 0 {
+	if code != 0 || stderr.String() != "plugin_schema_version=1\n" {
 		t.Fatalf("unexpected result: code=%d stderr=%q", code, stderr.String())
 	}
 	if got := len(fake.calls); got != 3 {

schema/v1.json

@@ -0,0 +1,88 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://registry.semrel.io/schemas/plugins/hook-gitplugin/v1.json",
+  "title": "hook-gitplugin plugin configuration",
+  "description": "Schema v1 for the hook-gitplugin semrel plugin. Configure via SEMREL_* environment variables.",
+  "type": "object",
+  "properties": {
+    "SEMREL_PLUGIN_FILES": {
+      "type": "string",
+      "description": "Comma-, semicolon-, or newline-separated file paths to include in the release commit."
+    },
+    "SEMREL_PLUGIN_COMMIT_MESSAGE": {
+      "type": "string",
+      "description": "Optional commit message override for the release commit."
+    },
+    "SEMREL_PLUGIN_BRANCH": {
+      "type": "string",
+      "description": "Optional branch override. Falls back to SEMREL_BRANCH."
+    },
+    "SEMREL_PLUGIN_REMOTE": {
+      "type": "string",
+      "default": "origin",
+      "description": "Git remote to push to."
+    },
+    "SEMREL_PLUGIN_TAG_NAME": {
+      "type": "string",
+      "description": "Optional tag name override. Falls back to SEMREL_TAG_NAME / SEMREL_VERSION / SEMREL_NEXT_VERSION."
+    },
+    "SEMREL_PLUGIN_TAG_MESSAGE": {
+      "type": "string",
+      "description": "Optional annotated tag message."
+    },
+    "SEMREL_PLUGIN_SIGN_TAG": {
+      "type": "string",
+      "enum": [
+        "true",
+        "false",
+        "1",
+        "0"
+      ],
+      "default": "false",
+      "description": "When true, create a signed tag."
+    },
+    "SEMREL_PLUGIN_SIGNED_OFF_BY": {
+      "type": "string",
+      "enum": [
+        "true",
+        "false",
+        "1",
+        "0"
+      ],
+      "default": "false",
+      "description": "When true, add a Signed-off-by line to the release commit."
+    },
+    "SEMREL_BRANCH": {
+      "type": "string",
+      "description": "Release branch name for the current semrel execution."
+    },
+    "SEMREL_TAG_NAME": {
+      "type": "string",
+      "description": "Release tag name for the current semrel execution."
+    },
+    "SEMREL_VERSION": {
+      "type": "string",
+      "description": "Release version for the current semrel execution. semrel core may expose this as SEMREL_VERSION, SEMREL_TAG_NAME, or SEMREL_NEXT_VERSION depending on phase."
+    },
+    "SEMREL_NEXT_VERSION": {
+      "type": "string",
+      "description": "Calculated next release version when SEMREL_VERSION is not yet finalized."
+    },
+    "SEMREL_TAG_PREFIX": {
+      "type": "string",
+      "description": "Tag prefix used by semrel core, for example \"v\"."
+    },
+    "SEMREL_DRY_RUN": {
+      "type": "string",
+      "enum": [
+        "true",
+        "false",
+        "1",
+        "0"
+      ],
+      "default": "false",
+      "description": "When true, perform validation and logging only without executing side effects."
+    }
+  },
+  "additionalProperties": true
+}