Fixes #9477 feat(nimbus): Add linter for FML (#9521)

Because

- We need a linter for the FML so that we can fetch errors for feature
configs

This commit

- First pass at an FML linter that will fetch errors from the FML and
parse them into `Diagnostic`s
- We do not have the endpoint yet that is going to fetch the errors
(#9480)
- Separates out some shared helpers for both schema linter and fml
linter
- Rename `schema.ts` to `validators.ts` so we can include the fml
linting in the same file. This can be separated out later if need be

experimenter/experimenter/nimbus-ui/src/components/PageEditBranches/FormBranches/FormFeatureValue/RichFeatureValueEditor.tsx

@@ -11,9 +11,12 @@ import React, { useCallback, useMemo, useRef } from "react";
 import { useController, useFormContext } from "react-hook-form";
 import { FeatureValueEditorProps } from "src/components/PageEditBranches/FormBranches/FormFeatureValue/props";
 import {
+  fmlLinter,
   schemaAutocomplete,
   schemaLinter,
-} from "src/components/PageEditBranches/FormBranches/FormFeatureValue/schema";
+} from "src/components/PageEditBranches/FormBranches/FormFeatureValue/validators";
+
+const allowFmlLinting = false;
 
 export default function RichFeatureValueEditor({
   featureConfig,
@@ -81,8 +84,11 @@ export default function RichFeatureValueEditor({
     ];
 
     if (schema) {
-      extensions.push(linter(schemaLinter(schema)));
-
+      if (allowFmlLinting) {
+        extensions.push(linter(fmlLinter()));
+      } else {
+        extensions.push(linter(schemaLinter(schema)));
+      }
       const completionSource = schemaAutocomplete(schema);
       if (completionSource) {
         extensions.push(

experimenter/experimenter/nimbus-ui/src/components/PageEditBranches/FormBranches/FormFeatureValue/validators.test.ts

@@ -3,10 +3,11 @@ import { EditorState, EditorStateConfig } from "@codemirror/state";
 import { basicSetup } from "codemirror";
 import {
   detectDraft,
+  fmlLinter,
   schemaAutocomplete,
   schemaLinter,
   simpleObjectSchema,
-} from "src/components/PageEditBranches/FormBranches/FormFeatureValue/schema";
+} from "src/components/PageEditBranches/FormBranches/FormFeatureValue/validators";
 import { z } from "zod";
 
 const SIMPLE_SCHEMA: z.infer<typeof simpleObjectSchema> = {
@@ -329,3 +330,37 @@ describe("detectDraft", () => {
     },
   );
 });
+
+describe("fmlLinter", () => {
+  it.each(["", "   ", "\t", "\n", " \n \t "])(
+    "does not return fml errors for an empty document",
+    (doc) => {
+      const linter = fmlLinter();
+      const state = createEditorState({ doc: JSON.stringify(doc) });
+      const diagnostics = linter({ state });
+      expect(diagnostics).toEqual([]);
+    },
+  );
+
+  it.each([`{"foo": {"error"}`, `{"error": {"bingo"}`])(
+    "returns FML errors",
+    (doc) => {
+      const linter = fmlLinter();
+      const message = { message: "oh no!" };
+      const state = createEditorState({ doc: JSON.stringify(doc) });
+      const diagnostics = linter({ state });
+      expect(diagnostics).toContainEqual(expect.objectContaining(message));
+    },
+  );
+
+  it.each([`{"foo": {"bar"}`, `{"foo": {"mimsy"}`])(
+    "does not returns FML errors",
+    (doc) => {
+      const linter = fmlLinter();
+      const message = { message: "oh no!" };
+      const state = createEditorState({ doc: JSON.stringify(doc) });
+      const diagnostics = linter({ state });
+      expect(diagnostics).not.toContainEqual(expect.objectContaining(message));
+    },
+  );
+});

experimenter/experimenter/nimbus-ui/src/components/PageEditBranches/FormBranches/FormFeatureValue/validators.ts

@@ -6,6 +6,7 @@ import { Text } from "@codemirror/state";
 import { EditorView } from "@codemirror/view";
 import jsonToAst from "json-to-ast";
 import { z } from "zod";
+
 /**
  * A simplified schema that is generated by a feature manifest entry with only a
  * simple list of variables.
@@ -201,12 +202,7 @@ export function schemaLinter(schema: Record<string, unknown>) {
         pos.end.column - 1,
       );
 
-      diagnostics.push({
-        from,
-        to,
-        message,
-        severity: "error",
-      });
+      diagnostics.push(createDiagnostic(from, to, message));
     }
 
     reportFloatValues(view.state.doc, rootNode, diagnostics);
@@ -222,6 +218,23 @@ function documentPosition(doc: Text, line: number, column: number): number {
   return doc.line(line).from + column;
 }
 
+/**
+ * Parse an error into a Diagnostic
+ */
+function createDiagnostic(
+  from: number,
+  to: number,
+  message: string,
+  severity = "error",
+): Diagnostic {
+  return {
+    from: from,
+    to: to,
+    message: message,
+    severity: severity,
+  } as Diagnostic;
+}
+
 interface FindNodeResult {
   value: jsonToAst.ValueNode;
   key?: jsonToAst.IdentifierNode;
@@ -280,12 +293,13 @@ function reportFloatValues(
     case "Literal":
       if (typeof node.value === "number" && ~~node.value !== node.value) {
         const loc = node.loc!;
-        diagnostics.push({
-          from: documentPosition(doc, loc.start.line, loc.start.column),
-          to: documentPosition(doc, loc.start.line, loc.start.column),
-          severity: "error",
-          message: "Floats are not supported",
-        });
+        diagnostics.push(
+          createDiagnostic(
+            documentPosition(doc, loc.start.line, loc.start.column),
+            documentPosition(doc, loc.start.line, loc.start.column),
+            "Floats are not supported",
+          ),
+        );
       }
       break;
   }
@@ -332,3 +346,27 @@ export function schemaAutocomplete(schema: Record<string, unknown>) {
     return null;
   };
 }
+
+/**
+ * Parse from FML errors to Diagnostics
+ */
+function parseFmlErrors(view: TestableEditorView): Diagnostic[] {
+  const diagnostics: Diagnostic[] = [];
+
+  const doc = view.state.doc;
+  const text = doc.toString();
+  const from = text.indexOf("error");
+  if (from === -1) return diagnostics;
+
+  const to = from + "error".length;
+
+  diagnostics.push(createDiagnostic(from, to, "oh no!"));
+  return diagnostics;
+}
+
+export function fmlLinter() {
+  return function (view: TestableEditorView) {
+    // TODO call endpoint to retrieve errors, remove temp error highlighting
+    return parseFmlErrors(view);
+  };
+}