fix(editor): bound SQL completion to active statement

apps/desktop/src/lib/__tests__/sql/sqlCompletion.syntaxTree.spec.ts

@@ -0,0 +1,75 @@
+import * as langSql from "@codemirror/lang-sql";
+import { ensureSyntaxTree } from "@codemirror/language";
+import { EditorState } from "@codemirror/state";
+import { describe, expect, it } from "vitest";
+import { createDbxCodeMirrorSqlDialect } from "@/lib/editor/codemirrorSqlDialect";
+import { isSqlCompletionSuppressedContext, isSqlLikeCompletionStatement } from "@/lib/sql/sqlCompletion";
+import { buildSqlSemanticModel } from "@/lib/sql/semantic/model";
+
+// Forces CM6's background parse to completion so tests are deterministic. Production code never
+// does this -- see sqlSyntaxTreeWindow.ts's doc comment.
+function stateFor(doc: string): EditorState {
+  const state = EditorState.create({
+    doc,
+    extensions: [langSql.sql({ dialect: createDbxCodeMirrorSqlDialect(langSql, "postgres", "postgres") })],
+  });
+  ensureSyntaxTree(state, doc.length, 5_000);
+  return state;
+}
+
+describe("isSqlCompletionSuppressedContext with a live EditorState", () => {
+  it("suppresses completion inside the maintainer's round-4 counterexample (unterminated string with 120,000 repeated ';') where the pure-string fallback gets the boundary wrong", () => {
+    const sql = `SELECT 'unterminated ${";".repeat(120_000)}`;
+    const cursor = sql.length - 5;
+    const state = stateFor(sql);
+
+    // Pure-string call (no live EditorState): exercises the documented bounded fallback, which
+    // is the path affected by the still-open, disclosed heuristic limitation.
+    const withoutTree = isSqlCompletionSuppressedContext(sql, cursor, { databaseType: "postgres" });
+    // With the live EditorState: resolved via the syntax tree, which correctly sees this whole
+    // 50,000-character run as one unterminated string literal.
+    const withTree = isSqlCompletionSuppressedContext(sql, cursor, { databaseType: "postgres", editorState: state });
+
+    expect(withTree).toBe(true);
+    // Documents the contrast, not a requirement: the pure-string fallback (no live EditorState)
+    // still exhibits the maintainer's exact round-4 counterexample, because it's unchanged --
+    // see insertValueHints.ts's doc comment and the reframed test in insertValueHints.test.ts. A
+    // real editor session always has a live EditorState, so `withTree` (asserted above) is what
+    // actually reaches a user typing in the editor.
+    expect(withoutTree).toBe(false);
+  });
+
+  it("does not suppress completion on real code immediately before the unterminated string opens", () => {
+    const sql = `SELECT id, ${";".repeat(50)}'unterminated forever`;
+    const cursor = sql.indexOf("id") + 1;
+    const state = stateFor(sql);
+
+    expect(isSqlCompletionSuppressedContext(sql, cursor, { databaseType: "postgres", editorState: state })).toBe(false);
+  });
+});
+
+describe("isSqlLikeCompletionStatement with a live EditorState", () => {
+  it("resolves the active statement via the syntax tree for a cursor deep inside a large document", () => {
+    const filler = Array.from({ length: 2_000 }, (_, index) => `-- comment line ${index}\n`).join("");
+    const sql = `${filler}SELECT id FROM users WHERE `;
+    const cursor = sql.length;
+    const state = stateFor(sql);
+
+    expect(isSqlLikeCompletionStatement(sql, cursor, { databaseType: "postgres", editorState: state })).toBe(true);
+  });
+
+  it("builds the completion semantic model from only the active statement", () => {
+    const filler = Array.from({ length: 4_000 }, (_, index) => `SELECT ${index};\n`).join("");
+    const activeStatement = "SELECT u. FROM users u";
+    const sql = filler + activeStatement;
+    const cursor = sql.indexOf("u. FROM", filler.length) + 2;
+    const state = stateFor(sql);
+
+    const model = buildSqlSemanticModel(sql, cursor, { databaseType: "postgres", editorState: state });
+
+    expect(model.statement.text).toBe(activeStatement);
+    expect(model.rowSources).toEqual([expect.objectContaining({ name: "users", alias: "u" })]);
+    expect(model.tokens.length).toBeLessThan(10);
+    expect(model.tokens.every((token) => token.span.start >= filler.length)).toBe(true);
+  });
+});