fix(plugins): sanitize env before spawning git so /plugin marketplace add works (#751)

Git 2.30+ refuses to start when any environment value contains a NUL,
CR, or LF character ("Unsafe environment: control characters are not
allowed in values"). User shells frequently leak such values — a
copy-pasted API key with a trailing newline, a terminal-set variable
with embedded escape sequences — which made every /plugin marketplace
add and /plugin install fail with that error before git even ran.

Add a small shared helper that builds the env passed to git child
processes and drops keys whose name or value contains a control
character. The legacy GIT_NO_PROMPT_ENV overrides (terminal prompt
disabled, askpass cleared) move into the same helper. Apply it to
every git invocation in marketplaceManager.ts (5 sites: gitPull,
gitClone, sparse-checkout, post-sparse checkout, reconcileSparseCheckout)
and pluginLoader.ts (8 sites: clone, fetch, checkout in both gitClone
and installFromGitSubdir).

A debug-level warning is logged once per process listing the dropped
key NAMES (not values) so the user can clean them up in their shell.

- src/utils/plugins/gitEnv.ts (new): sanitizeEnvForGit + buildGitChildEnv
- src/utils/plugins/gitEnv.test.ts (new): 10 unit tests covering CR/LF/NUL
  in values, control char in key name, undefined values, defaults,
  extras override
- src/utils/plugins/marketplaceManager.ts: replace 5 inline env spreads
  with buildGitChildEnv()
- src/utils/plugins/pluginLoader.ts: pass env: buildGitChildEnv() to 8
  git exec sites that previously inherited process.env unfiltered

Verified locally on Linux: before fix, git --version with a leaked
control-char env value fails with "Unsafe environment"; after fix it
runs cleanly. Live marketplaceManager.gitClone against a real GitHub
repo with the same leaked env succeeds and the repo is materialized
on disk.

src/utils/plugins/gitEnv.test.ts

@@ -0,0 +1,104 @@
+import { afterEach, beforeEach, describe, expect, test } from 'bun:test'
+
+import {
+  __resetGitEnvWarningForTesting,
+  buildGitChildEnv,
+  sanitizeEnvForGit,
+} from './gitEnv.js'
+
+describe('sanitizeEnvForGit', () => {
+  test('drops values containing LF', () => {
+    const result = sanitizeEnvForGit({
+      GOOD: 'value',
+      BAD_NEWLINE: 'line1\nline2',
+    })
+    expect(result.env).toEqual({ GOOD: 'value' })
+    expect(result.dropped).toEqual(['BAD_NEWLINE'])
+  })
+
+  test('drops values containing CR', () => {
+    const result = sanitizeEnvForGit({
+      GOOD: 'value',
+      BAD_CR: 'value\r',
+    })
+    expect(result.dropped).toEqual(['BAD_CR'])
+  })
+
+  test('drops values containing NUL', () => {
+    const result = sanitizeEnvForGit({
+      GOOD: 'value',
+      BAD_NUL: 'a\0b',
+    })
+    expect(result.dropped).toEqual(['BAD_NUL'])
+  })
+
+  test('drops keys whose name itself contains a control character', () => {
+    const result = sanitizeEnvForGit({
+      'BAD\nKEY': 'safe-value',
+      GOOD: 'value',
+    })
+    expect(result.env).toEqual({ GOOD: 'value' })
+    expect(result.dropped).toEqual(['BAD\nKEY'])
+  })
+
+  test('skips entries explicitly set to undefined without listing them as dropped', () => {
+    const result = sanitizeEnvForGit({
+      GOOD: 'value',
+      MAYBE: undefined,
+    })
+    expect(result.env).toEqual({ GOOD: 'value' })
+    expect(result.dropped).toEqual([])
+  })
+
+  test('returns input unchanged when nothing is unsafe', () => {
+    const env = { PATH: '/usr/bin:/bin', HOME: '/home/user', GIT_TERMINAL_PROMPT: '0' }
+    const result = sanitizeEnvForGit(env)
+    expect(result.env).toEqual(env)
+    expect(result.dropped).toEqual([])
+  })
+})
+
+describe('buildGitChildEnv', () => {
+  const ORIGINAL_BAD_KEY = 'OPENCLAUDE_TEST_BAD_ENV_FOR_GIT'
+  let originalValue: string | undefined
+
+  beforeEach(() => {
+    __resetGitEnvWarningForTesting()
+    originalValue = process.env[ORIGINAL_BAD_KEY]
+  })
+
+  afterEach(() => {
+    if (originalValue === undefined) {
+      delete process.env[ORIGINAL_BAD_KEY]
+    } else {
+      process.env[ORIGINAL_BAD_KEY] = originalValue
+    }
+  })
+
+  test('always sets the no-prompt overrides', () => {
+    const env = buildGitChildEnv()
+    expect(env.GIT_TERMINAL_PROMPT).toBe('0')
+    expect(env.GIT_ASKPASS).toBe('')
+  })
+
+  test('drops process.env values containing control characters (issue #751)', () => {
+    process.env[ORIGINAL_BAD_KEY] = 'paste-with-newline\n'
+    const env = buildGitChildEnv()
+    expect(env[ORIGINAL_BAD_KEY]).toBeUndefined()
+    expect(env.GIT_TERMINAL_PROMPT).toBe('0')
+  })
+
+  test('caller extras override process.env and the no-prompt defaults', () => {
+    const env = buildGitChildEnv({
+      GIT_TERMINAL_PROMPT: '1',
+      CUSTOM_KEY: 'custom-value',
+    })
+    expect(env.GIT_TERMINAL_PROMPT).toBe('1')
+    expect(env.CUSTOM_KEY).toBe('custom-value')
+  })
+
+  test('caller-provided unsafe extras are also dropped', () => {
+    const env = buildGitChildEnv({ EXTRA_BAD: 'a\rb' })
+    expect(env.EXTRA_BAD).toBeUndefined()
+  })
+})

src/utils/plugins/gitEnv.ts

@@ -0,0 +1,70 @@
+import { logForDebugging } from '../debug.js'
+
+/**
+ * Git 2.30+ refuses to start when any environment value contains a NUL,
+ * CR, or LF character ("Unsafe environment: control characters are not
+ * allowed in values"). User shells frequently leak such values — a
+ * copy-pasted API key with a trailing newline, or a terminal-set
+ * variable with embedded escape sequences — which would otherwise break
+ * every plugin clone or pull. We drop offending entries before forwarding
+ * the environment to git.
+ */
+const GIT_UNSAFE_VALUE_RE = /[\0\r\n]/
+
+const GIT_NO_PROMPT_ENV = {
+  GIT_TERMINAL_PROMPT: '0', // Prevent terminal credential prompts
+  GIT_ASKPASS: '', // Disable askpass GUI programs
+}
+
+let warnedAboutDroppedEnvKeys = false
+
+/**
+ * Returns a copy of `env` with any entries whose key OR value contains
+ * a NUL/CR/LF removed. The list of dropped key names is returned so
+ * callers can log it without exposing the (possibly secret) values.
+ */
+export function sanitizeEnvForGit(
+  env: NodeJS.ProcessEnv,
+): { env: NodeJS.ProcessEnv; dropped: string[] } {
+  const sanitized: NodeJS.ProcessEnv = {}
+  const dropped: string[] = []
+  for (const [key, value] of Object.entries(env)) {
+    if (value === undefined) continue
+    if (GIT_UNSAFE_VALUE_RE.test(key) || GIT_UNSAFE_VALUE_RE.test(value)) {
+      dropped.push(key)
+      continue
+    }
+    sanitized[key] = value
+  }
+  return { env: sanitized, dropped }
+}
+
+/**
+ * Build the environment object passed to a git child process. Merges
+ * `process.env` with the no-prompt overrides and any caller extras,
+ * then strips entries that would trigger git's unsafe-value check. The
+ * first batch of dropped key names is logged once per process so the
+ * user can clean them up in their shell.
+ */
+export function buildGitChildEnv(
+  extras?: NodeJS.ProcessEnv,
+): NodeJS.ProcessEnv {
+  const merged = { ...process.env, ...GIT_NO_PROMPT_ENV, ...(extras ?? {}) }
+  const { env, dropped } = sanitizeEnvForGit(merged)
+  if (dropped.length > 0 && !warnedAboutDroppedEnvKeys) {
+    warnedAboutDroppedEnvKeys = true
+    logForDebugging(
+      `git child env: dropped ${dropped.length} key(s) containing control characters: ${dropped.join(', ')}. Git 2.30+ rejects them; clean these up in your shell to forward them to git.`,
+      { level: 'warn' },
+    )
+  }
+  return env
+}
+
+/**
+ * Test-only escape hatch that resets the once-per-process warning flag
+ * so unit tests can exercise the warning path repeatedly.
+ */
+export function __resetGitEnvWarningForTesting(): void {
+  warnedAboutDroppedEnvKeys = false
+}

src/utils/plugins/marketplaceManager.ts

@@ -53,6 +53,7 @@ import {
   getAddDirExtraMarketplaces,
 } from './addDirPluginSettings.js'
 import { markPluginVersionOrphaned } from './cacheUtils.js'
+import { buildGitChildEnv } from './gitEnv.js'
 import { classifyFetchError, logPluginFetch } from './fetchTelemetry.js'
 import { removeAllPluginsForMarketplace } from './installedPluginsManager.js'
 import {
@@ -506,11 +507,6 @@ function seedDirFor(installLocation: string): string | undefined {
  * Provides helpful error messages for common failure scenarios.
  * If a ref is specified, fetches and checks out that specific branch or tag.
  */
-// Environment variables to prevent git from prompting for credentials
-const GIT_NO_PROMPT_ENV = {
-  GIT_TERMINAL_PROMPT: '0', // Prevent terminal credential prompts
-  GIT_ASKPASS: '', // Disable askpass GUI programs
-}
 
 const DEFAULT_PLUGIN_GIT_TIMEOUT_MS = 120 * 1000
 
@@ -531,7 +527,7 @@ export async function gitPull(
   options?: { disableCredentialHelper?: boolean; sparsePaths?: string[] },
 ): Promise<{ code: number; stderr: string }> {
   logForDebugging(`git pull: cwd=${cwd} ref=${ref ?? 'default'}`)
-  const env = { ...process.env, ...GIT_NO_PROMPT_ENV }
+  const env = buildGitChildEnv()
   const baseArgs = ['-c', 'core.hooksPath=/dev/null']
   const credentialArgs = options?.disableCredentialHelper
     ? ['-c', 'credential.helper=']
@@ -844,7 +840,7 @@ export async function gitClone(
   const result = await execFileNoThrowWithCwd(gitExe(), args, {
     timeout: timeoutMs,
     stdin: 'ignore',
-    env: { ...process.env, ...GIT_NO_PROMPT_ENV },
+    env: buildGitChildEnv(),
   })
 
   // Scrub credentials from execa's error/stderr fields before any logging or
@@ -870,7 +866,7 @@ export async function gitClone(
           cwd: targetPath,
           timeout: timeoutMs,
           stdin: 'ignore',
-          env: { ...process.env, ...GIT_NO_PROMPT_ENV },
+          env: buildGitChildEnv(),
         },
       )
       if (sparseResult.code !== 0) {
@@ -889,7 +885,7 @@ export async function gitClone(
           cwd: targetPath,
           timeout: timeoutMs,
           stdin: 'ignore',
-          env: { ...process.env, ...GIT_NO_PROMPT_ENV },
+          env: buildGitChildEnv(),
         },
       )
       if (checkoutResult.code !== 0) {
@@ -1040,7 +1036,7 @@ export async function reconcileSparseCheckout(
   cwd: string,
   sparsePaths: string[] | undefined,
 ): Promise<{ code: number; stderr: string }> {
-  const env = { ...process.env, ...GIT_NO_PROMPT_ENV }
+  const env = buildGitChildEnv()
 
   if (sparsePaths && sparsePaths.length > 0) {
     return execFileNoThrowWithCwd(

src/utils/plugins/pluginLoader.ts

@@ -87,6 +87,7 @@ import { getAddDirEnabledPlugins } from './addDirPluginSettings.js'
 import { verifyAndDemote } from './dependencyResolver.js'
 import { classifyFetchError, logPluginFetch } from './fetchTelemetry.js'
 import { checkGitAvailable } from './gitAvailability.js'
+import { buildGitChildEnv } from './gitEnv.js'
 import { getInMemoryInstalledPlugins } from './installedPluginsManager.js'
 import { getManagedPluginNames } from './managedPlugins.js'
 import {
@@ -560,7 +561,9 @@ export async function gitClone(
   args.push(gitUrl, targetPath)
 
   const cloneStarted = performance.now()
-  const cloneResult = await execFileNoThrow(gitExe(), args)
+  const cloneResult = await execFileNoThrow(gitExe(), args, {
+    env: buildGitChildEnv(),
+  })
 
   if (cloneResult.code !== 0) {
     logPluginFetch(
@@ -579,7 +582,7 @@ export async function gitClone(
     const shallowFetchResult = await execFileNoThrowWithCwd(
       gitExe(),
       ['fetch', '--depth', '1', 'origin', sha],
-      { cwd: targetPath },
+      { cwd: targetPath, env: buildGitChildEnv() },
     )
 
     if (shallowFetchResult.code !== 0) {
@@ -591,7 +594,7 @@ export async function gitClone(
       const unshallowResult = await execFileNoThrowWithCwd(
         gitExe(),
         ['fetch', '--unshallow'],
-        { cwd: targetPath },
+        { cwd: targetPath, env: buildGitChildEnv() },
       )
 
       if (unshallowResult.code !== 0) {
@@ -612,7 +615,7 @@ export async function gitClone(
     const checkoutResult = await execFileNoThrowWithCwd(
       gitExe(),
       ['checkout', sha],
-      { cwd: targetPath },
+      { cwd: targetPath, env: buildGitChildEnv() },
     )
 
     if (checkoutResult.code !== 0) {
@@ -745,7 +748,9 @@ export async function installFromGitSubdir(
   }
   cloneArgs.push(gitUrl, cloneDir)
 
-  const cloneResult = await execFileNoThrow(gitExe(), cloneArgs)
+  const cloneResult = await execFileNoThrow(gitExe(), cloneArgs, {
+    env: buildGitChildEnv(),
+  })
   if (cloneResult.code !== 0) {
     throw new Error(
       `Failed to clone repository for git-subdir source: ${cloneResult.stderr}`,
@@ -756,7 +761,7 @@ export async function installFromGitSubdir(
     const sparseResult = await execFileNoThrowWithCwd(
       gitExe(),
       ['sparse-checkout', 'set', '--cone', '--', subdirPath],
-      { cwd: cloneDir },
+      { cwd: cloneDir, env: buildGitChildEnv() },
     )
     if (sparseResult.code !== 0) {
       throw new Error(
@@ -775,7 +780,7 @@ export async function installFromGitSubdir(
       const fetchSha = await execFileNoThrowWithCwd(
         gitExe(),
         ['fetch', '--depth', '1', 'origin', sha],
-        { cwd: cloneDir },
+        { cwd: cloneDir, env: buildGitChildEnv() },
       )
       if (fetchSha.code !== 0) {
         logForDebugging(
@@ -784,7 +789,7 @@ export async function installFromGitSubdir(
         const unshallow = await execFileNoThrowWithCwd(
           gitExe(),
           ['fetch', '--unshallow'],
-          { cwd: cloneDir },
+          { cwd: cloneDir, env: buildGitChildEnv() },
         )
         if (unshallow.code !== 0) {
           throw new Error(`Failed to fetch commit ${sha}: ${unshallow.stderr}`)
@@ -793,7 +798,7 @@ export async function installFromGitSubdir(
       const checkout = await execFileNoThrowWithCwd(
         gitExe(),
         ['checkout', sha],
-        { cwd: cloneDir },
+        { cwd: cloneDir, env: buildGitChildEnv() },
       )
       if (checkout.code !== 0) {
         throw new Error(`Failed to checkout commit ${sha}: ${checkout.stderr}`)
@@ -808,9 +813,11 @@ export async function installFromGitSubdir(
       const [checkout, revParse] = await Promise.all([
         execFileNoThrowWithCwd(gitExe(), ['checkout', 'HEAD'], {
           cwd: cloneDir,
+          env: buildGitChildEnv(),
         }),
         execFileNoThrowWithCwd(gitExe(), ['rev-parse', 'HEAD'], {
           cwd: cloneDir,
+          env: buildGitChildEnv(),
         }),
       ])
       if (checkout.code !== 0) {