Show empty schema in upload settings (#30629)

* use syncable_schemas endpoint for upload settings

* add syncable_schemas endpoint to mock

* add e2e test for empty schema

e2e/test/scenarios/collections/uploads.cy.spec.js

-import { restore, queryWritableDB, resyncDatabase } from "e2e/support/helpers";
+import {
+  restore,
+  queryWritableDB,
+  resyncDatabase,
+  popover,
+} from "e2e/support/helpers";
 
 import { WRITABLE_DB_ID } from "e2e/support/cypress_data";
 
@@ -18,6 +23,58 @@ const testFiles = [
 ];
 
 describe("CSV Uploading", { tags: ["@external", "@actions"] }, () => {
+  it("Can upload a CSV file to an empty postgres schema", () => {
+    const testFile = testFiles[0];
+    const EMPTY_SCHEMA_NAME = "empty_uploads";
+
+    cy.intercept("PUT", "/api/setting").as("saveSettings");
+
+    restore("postgres-writable");
+    cy.signInAsAdmin();
+
+    queryWritableDB("DROP SCHEMA IF EXISTS empty_uploads CASCADE;", "postgres");
+    queryWritableDB("CREATE SCHEMA IF NOT EXISTS empty_uploads;", "postgres");
+
+    cy.request("POST", "/api/collection", {
+      name: `Uploads Collection`,
+      color: "#000000", // shockingly, this unused field is required
+      parent_id: null,
+    }).then(({ body: { id: collectionId } }) => {
+      cy.wrap(collectionId).as("collectionId");
+    });
+    resyncDatabase({ dbId: WRITABLE_DB_ID });
+    cy.visit("/admin/settings/uploads");
+
+    cy.findByLabelText("Upload Settings Form")
+      .findByText("Select a database")
+      .click();
+    popover().findByText("Writable Postgres12").click();
+    cy.findByLabelText("Upload Settings Form")
+      .findByText("Select a schema")
+      .click();
+
+    popover().findByText(EMPTY_SCHEMA_NAME).click();
+
+    cy.findByLabelText("Upload Settings Form").button("Enable uploads").click();
+
+    cy.wait("@saveSettings");
+
+    uploadFile(testFile, "postgres");
+
+    const tableQuery = `SELECT * FROM information_schema.tables WHERE table_name LIKE '%${testFile.tableName}_%' ORDER BY table_name DESC LIMIT 1;`;
+
+    queryWritableDB(tableQuery, "postgres").then(result => {
+      expect(result.rows.length).to.equal(1);
+      const tableName = result.rows[0].table_name;
+      queryWritableDB(
+        `SELECT count(*) FROM ${EMPTY_SCHEMA_NAME}.${tableName};`,
+        "postgres",
+      ).then(result => {
+        expect(Number(result.rows[0].count)).to.equal(testFile.rowCount);
+      });
+    });
+  });
+
   ["postgres"].forEach(dialect => {
     describe(`CSV Uploading (${dialect})`, () => {
       beforeEach(() => {
@@ -37,42 +94,7 @@ describe("CSV Uploading", { tags: ["@external", "@actions"] }, () => {
 
       testFiles.forEach(testFile => {
         it(`Can upload ${testFile.fileName} to a collection`, () => {
-          cy.get("@collectionId").then(collectionId =>
-            cy.visit(`/collection/${collectionId}`),
-          );
-
-          cy.fixture(`${FIXTURE_PATH}/${testFile.fileName}`).then(file => {
-            cy.get("#upload-csv").selectFile(
-              {
-                contents: Cypress.Buffer.from(file),
-                fileName: testFile.fileName,
-                mimeType: "text/csv",
-              },
-              { force: true },
-            );
-          });
-
-          cy.findByRole("status").within(() => {
-            cy.findByText(/Uploading/i);
-            cy.findByText(testFile.fileName);
-
-            cy.findByText("Data added to Uploads Collection", {
-              timeout: 10 * 1000,
-            });
-          });
-
-          cy.get("main").within(() => cy.findByText("Uploads Collection"));
-
-          cy.findByTestId("collection-table").within(() => {
-            cy.findByText(testFile.tableName); // TODO: we should humanize model names
-          });
-
-          cy.findByRole("status").within(() => {
-            cy.findByText("Start exploring").click();
-          });
-
-          cy.url().should("include", `/model/4`);
-          cy.findByTestId("TableInteractive-root");
+          uploadFile(testFile, dialect);
 
           const tableQuery = `SELECT * FROM information_schema.tables WHERE table_name LIKE '%${testFile.tableName}_%' ORDER BY table_name DESC LIMIT 1;`;
 
@@ -93,6 +115,45 @@ describe("CSV Uploading", { tags: ["@external", "@actions"] }, () => {
   });
 });
 
+function uploadFile(testFile, dialect) {
+  cy.get("@collectionId").then(collectionId =>
+    cy.visit(`/collection/${collectionId}`),
+  );
+
+  cy.fixture(`${FIXTURE_PATH}/${testFile.fileName}`).then(file => {
+    cy.get("#upload-csv").selectFile(
+      {
+        contents: Cypress.Buffer.from(file),
+        fileName: testFile.fileName,
+        mimeType: "text/csv",
+      },
+      { force: true },
+    );
+  });
+
+  cy.findByRole("status").within(() => {
+    cy.findByText(/Uploading/i);
+    cy.findByText(testFile.fileName);
+
+    cy.findByText("Data added to Uploads Collection", {
+      timeout: 10 * 1000,
+    });
+  });
+
+  cy.get("main").within(() => cy.findByText("Uploads Collection"));
+
+  cy.findByTestId("collection-table").within(() => {
+    cy.findByText(testFile.tableName); // TODO: we should humanize model names
+  });
+
+  cy.findByRole("status").within(() => {
+    cy.findByText("Start exploring").click();
+  });
+
+  cy.url().should("include", `/model/4`);
+  cy.findByTestId("TableInteractive-root");
+}
+
 function enableUploads(dialect) {
   const settings = {
     "uploads-enabled": true,

frontend/src/metabase/admin/settings/components/UploadSettings/UploadSettings.tsx

@@ -190,7 +190,7 @@ export function UploadSettingsView({
           />
         </div>
         {!!showSchema && (
-          <Schemas.ListLoader query={{ dbId }}>
+          <Schemas.ListLoader query={{ dbId, getAll: true }}>
             {({ list: schemaList }: { list: Schema[] }) => (
               <div>
                 <SectionTitle>{t`Schema`}</SectionTitle>

frontend/src/metabase/entities/schemas.js

 import { updateIn } from "icepick";
 import { createEntity } from "metabase/lib/entities";
-
-import { GET } from "metabase/lib/api";
+import { MetabaseApi } from "metabase/services";
 
 import { SchemaSchema } from "metabase/schema";
 import Questions from "metabase/entities/questions";
@@ -16,19 +15,18 @@ import {
 
 // This is a weird entity because we don't have actual schema objects
 
-const listDatabaseSchemas = GET("/api/database/:dbId/schemas");
-const getSchemaTables = GET("/api/database/:dbId/schema/:schemaName");
-const getVirtualDatasetTables = GET("/api/database/:dbId/datasets/:schemaName");
-
 export default createEntity({
   name: "schemas",
   schema: SchemaSchema,
   api: {
-    list: async ({ dbId, ...args }) => {
+    list: async ({ dbId, getAll = false, ...args }) => {
       if (!dbId) {
         throw new Error("Schemas can only be listed for a particular dbId");
       }
-      const schemaNames = await listDatabaseSchemas({ dbId, ...args });
+      const schemaNames = await (getAll
+        ? MetabaseApi.db_syncable_schemas({ dbId, ...args }) // includes empty schema
+        : MetabaseApi.db_schemas({ dbId, ...args }));
+
       return schemaNames.map(schemaName => ({
         // NOTE: needs unique IDs for entities to work correctly
         id: generateSchemaId(dbId, schemaName),
@@ -42,8 +40,12 @@ export default createEntity({
         throw new Error("Schemas ID is of the form dbId:schemaName");
       }
       const tables = opts?.isDatasets
-        ? await getVirtualDatasetTables({ dbId, schemaName, ...args })
-        : await getSchemaTables({ dbId, schemaName, ...args });
+        ? await MetabaseApi.db_virtual_dataset_tables({
+            dbId,
+            schemaName,
+            ...args,
+          })
+        : await MetabaseApi.db_schema_tables({ dbId, schemaName, ...args });
       return {
         id,
         name: schemaName,

frontend/src/metabase/services.js

@@ -311,7 +311,9 @@ export const MetabaseApi = {
   db_delete: DELETE("/api/database/:dbId"),
   db_metadata: GET("/api/database/:dbId/metadata"),
   db_schemas: GET("/api/database/:dbId/schemas"),
+  db_syncable_schemas: GET("/api/database/:dbId/syncable_schemas"),
   db_schema_tables: GET("/api/database/:dbId/schema/:schemaName"),
+  db_virtual_dataset_tables: GET("/api/database/:dbId/datasets/:schemaName"),
   //db_tables:   GET("/api/database/:dbId/tables"),
   db_fields: GET("/api/database/:dbId/fields"),
   db_idfields: GET("/api/database/:dbId/idfields"),

frontend/test/__support__/server-mocks/database.ts

@@ -34,6 +34,7 @@ export const setupSchemaEndpoints = (db: Database) => {
   const schemas = _.groupBy(db.tables ?? [], table => table.schema);
   const schemaNames = Object.keys(schemas);
   fetchMock.get(`path:/api/database/${db.id}/schemas`, schemaNames);
+  fetchMock.get(`path:/api/database/${db.id}/syncable_schemas`, schemaNames);
 
   schemaNames.forEach(schema => {
     fetchMock.get(