Warn if `npm run start` is out of date. (#20)

* Adding some wiring to allow the Ink app to warn if there are local development changes that haven't been captured in the recent build of the Gemini CLI.

* Adding a new useAppEffects.ts file that wores some useEffect handlers in.

* Updating package-lock.json to resolve `npm ci` issues.

* Updating package-lock.json and package.json to resolve `npm ci` issues.

6 files changed, 226 insertions, 27 deletions

diff --git a/package-lock.json b/package-lock.json
index a9b283e6..8a4b1473 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -257,6 +257,10 @@
         "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
       }
     },
+    "node_modules/@google/gemini-code": {
+      "resolved": "packages/cli",
+      "link": true
+    },
     "node_modules/@google/genai": {
       "version": "0.8.0",
       "resolved": "https://registry.npmjs.org/@google/genai/-/genai-0.8.0.tgz",
@@ -2352,10 +2356,6 @@
         "node": ">=14"
       }
     },
-    "node_modules/gemini-code-cli": {
-      "resolved": "packages/cli",
-      "link": true
-    },
     "node_modules/get-caller-file": {
       "version": "2.0.5",
       "license": "ISC",
@@ -5194,7 +5194,7 @@
       "license": "MIT"
     },
     "packages/cli": {
-      "name": "gemini-code-cli",
+      "name": "@google/gemini-code",
       "version": "1.0.0",
       "dependencies": {
         "@google/genai": "^0.8.0",
diff --git a/package.json b/package.json
index 677c47da..2350340f 100644
--- a/package.json
+++ b/package.json
@@ -9,10 +9,9 @@
   "scripts": {
     "build": "npm run build --workspaces",
     "test": "npm run test --workspaces",
+    "start": "node ./scripts/check-build-status.js && npm run start --workspace=@google/gemini-code -- \"$@\"",
     "lint": "eslint . --ext .ts,.tsx",
     "typecheck": "tsc --noEmit --jsx react",
-    "start": "npm run start --workspace=@google/gemini-code -- \"$@\"",
-    "format": "prettier --write .",
     "artifactregistry-login": "npx google-artifactregistry-auth"
   },
   "devDependencies": {
diff --git a/packages/cli/package.json b/packages/cli/package.json
index 4f2ca5fe..053aeabc 100644
--- a/packages/cli/package.json
+++ b/packages/cli/package.json
@@ -5,8 +5,7 @@
   "type": "module",
   "main": "gemini.js",
   "scripts": {
-    "build": "tsc && cp package.json README.md ../../LICENSE dist/",
-    "clean": "rm -rf dist",
+    "build": "tsc && cp package.json README.md ../../LICENSE dist/ && touch dist/.last_build",
     "start": "node dist/gemini.js",
     "debug": "node --inspect-brk dist/gemini.js",
     "lint": "eslint . --ext .ts,.tsx",
diff --git a/packages/cli/src/ui/App.tsx b/packages/cli/src/ui/App.tsx
index 1bc0f6c6..7eae3727 100644
--- a/packages/cli/src/ui/App.tsx
+++ b/packages/cli/src/ui/App.tsx
@@ -1,5 +1,8 @@
 import React, { useState, useEffect } from 'react';
 import { Box, Text } from 'ink';
+import fs from 'fs';
+import path from 'path';
+import os from 'os';
 import type { HistoryItem } from './types.js';
 import { useGeminiStream } from './hooks/useGeminiStream.js';
 import { useLoadingIndicator } from './hooks/useLoadingIndicator.js';
@@ -11,6 +14,12 @@ import InputPrompt from './components/InputPrompt.js';
 import Footer from './components/Footer.js';
 import { StreamingState } from '../core/gemini-stream.js';
 import { PartListUnion } from '@google/genai';
+import {
+  useStartupWarnings,
+  useInitializationErrorEffect,
+} from './hooks/useAppEffects.js';
+
+const warningsFilePath = path.join(os.tmpdir(), 'gemini-code-cli-warnings.txt');
 
 interface AppProps {
   directory: string;
@@ -19,11 +28,15 @@ interface AppProps {
 const App = ({ directory }: AppProps) => {
   const [query, setQuery] = useState('');
   const [history, setHistory] = useState<HistoryItem[]>([]);
+  const [startupWarnings, setStartupWarnings] = useState<string[]>([]);
   const { streamingState, submitQuery, initError } =
     useGeminiStream(setHistory);
   const { elapsedTime, currentLoadingPhrase } =
     useLoadingIndicator(streamingState);
 
+  useStartupWarnings(setStartupWarnings);
+  useInitializationErrorEffect(initError, history, setHistory);
+
   const handleInputSubmit = (value: PartListUnion) => {
     submitQuery(value)
       .then(() => {
@@ -34,24 +47,6 @@ const App = ({ directory }: AppProps) => {
       });
   };
 
-  useEffect(() => {
-    if (
-      initError &&
-      !history.some(
-        (item) => item.type === 'error' && item.text?.includes(initError),
-      )
-    ) {
-      setHistory((prev) => [
-        ...prev,
-        {
-          id: Date.now(),
-          type: 'error',
-          text: `Initialization Error: ${initError}. Please check API key and configuration.`,
-        } as HistoryItem,
-      ]);
-    }
-  }, [initError, history]);
-
   const isWaitingForToolConfirmation = history.some(
     (item) =>
       item.type === 'tool_group' &&
@@ -63,6 +58,22 @@ const App = ({ directory }: AppProps) => {
     <Box flexDirection="column" padding={1} marginBottom={1} width="100%">
       <Header cwd={directory} />
 
+      {startupWarnings.length > 0 && (
+        <Box
+          borderStyle="round"
+          borderColor="yellow"
+          paddingX={1}
+          marginY={1}
+          flexDirection="column"
+        >
+          {startupWarnings.map((warning, index) => (
+            <Text key={index} color="yellow">
+              {warning}
+            </Text>
+          ))}
+        </Box>
+      )}
+
       <Tips />
 
       {initError &&
diff --git a/packages/cli/src/ui/hooks/useAppEffects.ts b/packages/cli/src/ui/hooks/useAppEffects.ts
new file mode 100644
index 00000000..16f862b0
--- /dev/null
+++ b/packages/cli/src/ui/hooks/useAppEffects.ts
@@ -0,0 +1,61 @@
+import { useEffect } from 'react';
+import fs from 'fs';
+import path from 'path';
+import os from 'os';
+import type { HistoryItem } from '../types.js';
+
+const warningsFilePath = path.join(os.tmpdir(), 'gemini-code-cli-warnings.txt');
+
+// Effect to handle startup warnings
+export function useStartupWarnings(
+  setStartupWarnings: React.Dispatch<React.SetStateAction<string[]>>,
+) {
+  useEffect(() => {
+    try {
+      if (fs.existsSync(warningsFilePath)) {
+        const warningsContent = fs.readFileSync(warningsFilePath, 'utf-8');
+        setStartupWarnings(
+          warningsContent.split('\n').filter((line) => line.trim() !== ''),
+        );
+        try {
+          fs.unlinkSync(warningsFilePath);
+        } catch (unlinkErr: any) {
+          setStartupWarnings((prev) => [
+            ...prev,
+            `Warning: Could not delete temporary warnings file.`,
+          ]);
+        }
+      }
+    } catch (err: any) {
+      setStartupWarnings((prev) => [
+        ...prev,
+        `Error checking/reading warnings file: ${err.message}`,
+      ]);
+    }
+  }, [setStartupWarnings]); // Include setStartupWarnings in dependency array
+}
+
+// Effect to handle initialization errors
+export function useInitializationErrorEffect(
+  initError: string | null,
+  history: HistoryItem[],
+  setHistory: React.Dispatch<React.SetStateAction<HistoryItem[]>>,
+) {
+  useEffect(() => {
+    if (
+      initError &&
+      !history.some(
+        (item) => item.type === 'error' && item.text?.includes(initError),
+      )
+    ) {
+      setHistory((prev) => [
+        ...prev,
+        {
+          id: Date.now(),
+          type: 'error',
+          text: `Initialization Error: ${initError}. Please check API key and configuration.`,
+        } as HistoryItem,
+      ]);
+    }
+  }, [initError, history, setHistory]); // Include setHistory in dependency array
+} 
\ No newline at end of file
diff --git a/scripts/check-build-status.js b/scripts/check-build-status.js
new file mode 100644
index 00000000..fd38d003
--- /dev/null
+++ b/scripts/check-build-status.js
@@ -0,0 +1,129 @@
+import fs from 'fs';
+import path from 'path';
+import os from 'os'; // Import os module
+
+// --- Configuration ---
+const cliPackageDir = path.resolve('packages', 'cli'); // Base directory for the CLI package
+const buildTimestampPath = path.join(cliPackageDir, 'dist', '.last_build'); // Path to the timestamp file within the CLI package
+const sourceDirs = [path.join(cliPackageDir, 'src')]; // Source directory within the CLI package
+const filesToWatch = [path.join(cliPackageDir, 'package.json'), path.join(cliPackageDir, 'tsconfig.json')]; // Specific files within the CLI package
+const buildDir = path.join(cliPackageDir, 'dist'); // Build output directory within the CLI package
+const warningsFilePath = path.join(os.tmpdir(), 'gemini-code-cli-warnings.txt'); // Temp file for warnings
+// ---------------------
+
+function getMtime(filePath) {
+  try {
+    return fs.statSync(filePath).mtimeMs; // Use mtimeMs for higher precision
+  } catch (err) {
+    if (err.code === 'ENOENT') {
+      return null; // File doesn't exist
+    }
+    console.error(`Error getting stats for ${filePath}:`, err);
+    process.exit(1); // Exit on unexpected errors getting stats
+  }
+}
+
+function findSourceFiles(dir, allFiles = []) {
+  const entries = fs.readdirSync(dir, { withFileTypes: true });
+  for (const entry of entries) {
+    const fullPath = path.join(dir, entry.name);
+    // Simple check to avoid recursing into node_modules or build dir itself
+    if (entry.isDirectory() && entry.name !== 'node_modules' && fullPath !== buildDir) {
+      findSourceFiles(fullPath, allFiles);
+    } else if (entry.isFile()) {
+      allFiles.push(fullPath);
+    }
+  }
+  return allFiles;
+}
+
+console.log('Checking build status...');
+
+// Clean up old warnings file before check
+try {
+  if (fs.existsSync(warningsFilePath)) {
+    fs.unlinkSync(warningsFilePath);
+  }
+} catch (err) {
+  console.warn(`[Check Script] Warning: Could not delete previous warnings file: ${err.message}`);
+}
+
+const buildMtime = getMtime(buildTimestampPath);
+if (!buildMtime) {
+  // If build is missing, write that as a warning and exit(0) so app can display it
+  const errorMessage = `ERROR: Build timestamp file (${path.relative(process.cwd(), buildTimestampPath)}) not found. Run \`npm run build\` first.`;
+  console.error(errorMessage); // Still log error here
+  try {
+    fs.writeFileSync(warningsFilePath, errorMessage);
+  } catch (writeErr) {
+     console.error(`[Check Script] Error writing missing build warning file: ${writeErr.message}`);
+  }
+  process.exit(0); // Allow app to start and show the error
+}
+
+let newerSourceFileFound = false;
+const warningMessages = []; // Collect warnings here
+const allSourceFiles = [];
+
+// Collect files from specified directories
+sourceDirs.forEach((dir) => {
+    const dirPath = path.resolve(dir);
+    if (fs.existsSync(dirPath)) {
+        findSourceFiles(dirPath, allSourceFiles);
+    } else {
+        console.warn(`Warning: Source directory "${dir}" not found.`);
+    }
+});
+
+// Add specific files
+filesToWatch.forEach((file) => {
+    const filePath = path.resolve(file);
+     if (fs.existsSync(filePath)) {
+        allSourceFiles.push(filePath);
+    } else {
+         console.warn(`Warning: Watched file "${file}" not found.`);
+    }
+});
+
+
+// Check modification times
+for (const file of allSourceFiles) {
+  const sourceMtime = getMtime(file);
+  const relativePath = path.relative(process.cwd(), file);
+  const isNewer = sourceMtime && sourceMtime > buildMtime;
+
+  if (isNewer) {
+    const warning = `Warning: Source file "${relativePath}" has been modified since the last build.`;
+    console.warn(warning); // Keep console warning for script debugging
+    warningMessages.push(warning);
+    newerSourceFileFound = true;
+    // break; // Uncomment to stop checking after the first newer file
+  }
+}
+
+if (newerSourceFileFound) {
+  const finalWarning = '\nRun "npm run build" to incorporate changes before starting.';
+  warningMessages.push(finalWarning);
+  console.warn(finalWarning);
+
+  // Write warnings to the temp file
+  try {
+    fs.writeFileSync(warningsFilePath, warningMessages.join('\n'));
+    // Removed debug log
+  } catch (err) {
+    console.error(`[Check Script] Error writing warnings file: ${err.message}`);
+    // Proceed without writing, app won't show warnings
+  }
+} else {
+  console.log('Build is up-to-date.');
+  // Ensure no stale warning file exists if build is ok
+  try {
+      if (fs.existsSync(warningsFilePath)) {
+          fs.unlinkSync(warningsFilePath);
+      }
+  } catch (err) {
+       console.warn(`[Check Script] Warning: Could not delete previous warnings file: ${err.message}`);
+  }
+}
+
+process.exit(0); // Always exit successfully so the app starts 
\ No newline at end of file