diff --git a/dev-infra/build-worker.js b/dev-infra/build-worker.js
index aad3843510..eb05917793 100644
--- a/dev-infra/build-worker.js
+++ b/dev-infra/build-worker.js
@@ -145,6 +145,7 @@ var GitCommandError = /** @class */ (function (_super) {
         // we sanitize the command that will be part of the error message.
         _super.call(this, "Command failed: git " + client.sanitizeConsoleOutput(args.join(' '))) || this;
         _this.args = args;
+        Object.setPrototypeOf(_this, GitCommandError.prototype);
         return _this;
     }
     return GitCommandError;
diff --git a/dev-infra/ng-dev.js b/dev-infra/ng-dev.js
index 7b7c2fb3d8..ee84e30658 100755
--- a/dev-infra/ng-dev.js
+++ b/dev-infra/ng-dev.js
@@ -317,6 +317,7 @@ var GitCommandError = /** @class */ (function (_super) {
         // we sanitize the command that will be part of the error message.
         _super.call(this, "Command failed: git " + client.sanitizeConsoleOutput(args.join(' '))) || this;
         _this.args = args;
+        Object.setPrototypeOf(_this, GitCommandError.prototype);
         return _this;
     }
     return GitCommandError;
@@ -3463,30 +3464,40 @@ function discoverNewConflictsForPr(newPrNumber, updatedAfter) {
         info(`Retrieved ${allPendingPRs.length} total pending PRs`);
         info(`Checking ${pendingPrs.length} PRs for conflicts after a merge of #${newPrNumber}`);
         // Fetch and checkout the PR being checked.
-        exec(`git fetch ${requestedPr.headRef.repository.url} ${requestedPr.headRef.name}`);
-        exec(`git checkout -B ${tempWorkingBranch} FETCH_HEAD`);
+        git.run(['fetch', '-q', requestedPr.headRef.repository.url, requestedPr.headRef.name]);
+        git.run(['checkout', '-q', '-B', tempWorkingBranch, 'FETCH_HEAD']);
         // Rebase the PR against the PRs target branch.
-        exec(`git fetch ${requestedPr.baseRef.repository.url} ${requestedPr.baseRef.name}`);
-        const result = exec(`git rebase FETCH_HEAD`);
-        if (result.code) {
-            error('The requested PR currently has conflicts');
-            cleanUpGitState(previousBranchOrRevision);
-            process.exit(1);
+        git.run(['fetch', '-q', requestedPr.baseRef.repository.url, requestedPr.baseRef.name]);
+        try {
+            git.run(['rebase', 'FETCH_HEAD'], { stdio: 'ignore' });
+        }
+        catch (err) {
+            if (err instanceof GitCommandError) {
+                error('The requested PR currently has conflicts');
+                git.checkout(previousBranchOrRevision, true);
+                process.exit(1);
+            }
+            throw err;
         }
         // Start the progress bar
         progressBar.start(pendingPrs.length, 0);
         // Check each PR to determine if it can merge cleanly into the repo after the target PR.
         for (const pr of pendingPrs) {
             // Fetch and checkout the next PR
-            exec(`git fetch ${pr.headRef.repository.url} ${pr.headRef.name}`);
-            exec(`git checkout --detach FETCH_HEAD`);
+            git.run(['fetch', '-q', pr.headRef.repository.url, pr.headRef.name]);
+            git.run(['checkout', '-q', '--detach', 'FETCH_HEAD']);
             // Check if the PR cleanly rebases into the repo after the target PR.
-            const result = exec(`git rebase ${tempWorkingBranch}`);
-            if (result.code !== 0) {
-                conflicts.push(pr);
+            try {
+                git.run(['rebase', tempWorkingBranch], { stdio: 'ignore' });
+            }
+            catch (err) {
+                if (err instanceof GitCommandError) {
+                    conflicts.push(pr);
+                }
+                throw err;
             }
             // Abort any outstanding rebase attempt.
-            exec(`git rebase --abort`);
+            git.runGraceful(['rebase', '--abort'], { stdio: 'ignore' });
             progressBar.increment(1);
         }
         // End the progress bar as all PRs have been processed.
@@ -5978,7 +5989,7 @@ const ReleaseNotesCommandModule = {
  *
  * @returns a Promise resolving on success, and rejecting on command failure with the status code.
  */
-function spawnInteractiveCommand(command, args, options) {
+function spawnInteractive(command, args, options) {
     if (options === void 0) { options = {}; }
     return new Promise(function (resolve, reject) {
         var commandText = command + " " + args.join(' ');
@@ -5993,9 +6004,9 @@ function spawnInteractiveCommand(command, args, options) {
  * output mode, stdout/stderr output is also printed to the console, or only on error.
  *
  * @returns a Promise resolving with captured stdout and stderr on success. The promise
- *   rejects on command failure.
+ *   rejects on command failure
  */
-function spawnWithDebugOutput(command, args, options) {
+function spawn(command, args, options) {
     if (options === void 0) { options = {}; }
     return new Promise(function (resolve, reject) {
         var commandText = command + " " + args.join(' ');
@@ -6025,15 +6036,16 @@ function spawnWithDebugOutput(command, args, options) {
                 process.stderr.write(message);
             }
         });
-        childProcess.on('exit', function (status, signal) {
-            var exitDescription = status !== null ? "exit code \"" + status + "\"" : "signal \"" + signal + "\"";
+        childProcess.on('exit', function (exitCode, signal) {
+            var exitDescription = exitCode !== null ? "exit code \"" + exitCode + "\"" : "signal \"" + signal + "\"";
             var printFn = outputMode === 'on-error' ? error : debug;
+            var status = statusFromExitCodeAndSignal(exitCode, signal);
             printFn("Command \"" + commandText + "\" completed with " + exitDescription + ".");
             printFn("Process output: \n" + logOutput);
             // On success, resolve the promise. Otherwise reject with the captured stderr
             // and stdout log output if the output mode was set to `silent`.
-            if (status === 0) {
-                resolve({ stdout: stdout, stderr: stderr });
+            if (status === 0 || options.suppressErrorOnFailingExitCode) {
+                resolve({ stdout: stdout, stderr: stderr, status: status });
             }
             else {
                 reject(outputMode === 'silent' ? logOutput : undefined);
@@ -6041,6 +6053,10 @@ function spawnWithDebugOutput(command, args, options) {
         });
     });
 }
+/** Convert the provided exitCode and signal to a single status code. */
+function statusFromExitCodeAndSignal(exitCode, signal) {
+    return exitCode !== null ? exitCode : signal !== null ? signal : -1;
+}
 
 /**
  * @license
@@ -6060,7 +6076,7 @@ function runNpmPublish(packagePath, distTag, registryUrl) {
         if (registryUrl !== undefined) {
             args.push('--registry', registryUrl);
         }
-        yield spawnWithDebugOutput('npm', args, { cwd: packagePath, mode: 'silent' });
+        yield spawn('npm', args, { cwd: packagePath, mode: 'silent' });
     });
 }
 /**
@@ -6074,7 +6090,7 @@ function setNpmTagForPackage(packageName, distTag, version, registryUrl) {
         if (registryUrl !== undefined) {
             args.push('--registry', registryUrl);
         }
-        yield spawnWithDebugOutput('npm', args, { mode: 'silent' });
+        yield spawn('npm', args, { mode: 'silent' });
     });
 }
 /**
@@ -6089,7 +6105,7 @@ function npmIsLoggedIn(registryUrl) {
             args.push('--registry', registryUrl);
         }
         try {
-            yield spawnWithDebugOutput('npm', args, { mode: 'silent' });
+            yield spawn('npm', args, { mode: 'silent' });
         }
         catch (e) {
             return false;
@@ -6112,7 +6128,7 @@ function npmLogin(registryUrl) {
         }
         // The login command prompts for username, password and other profile information. Hence
         // the process needs to be interactive (i.e. respecting current TTYs stdin).
-        yield spawnInteractiveCommand('npm', args);
+        yield spawnInteractive('npm', args);
     });
 }
 /**
@@ -6129,7 +6145,7 @@ function npmLogout(registryUrl) {
             args.splice(1, 0, '--registry', registryUrl);
         }
         try {
-            yield spawnWithDebugOutput('npm', args, { mode: 'silent' });
+            yield spawn('npm', args, { mode: 'silent' });
         }
         finally {
             return npmIsLoggedIn(registryUrl);
@@ -6251,7 +6267,7 @@ function invokeSetNpmDistCommand(npmDistTag, version) {
     return tslib.__awaiter(this, void 0, void 0, function* () {
         try {
             // Note: No progress indicator needed as that is the responsibility of the command.
-            yield spawnWithDebugOutput('yarn', ['--silent', 'ng-dev', 'release', 'set-dist-tag', npmDistTag, version.format()]);
+            yield spawn('yarn', ['--silent', 'ng-dev', 'release', 'set-dist-tag', npmDistTag, version.format()]);
             info(green(`  ✓   Set "${npmDistTag}" NPM dist tag for all packages to v${version}.`));
         }
         catch (e) {
@@ -6271,7 +6287,7 @@ function invokeReleaseBuildCommand() {
         try {
             // Since we expect JSON to be printed from the `ng-dev release build` command,
             // we spawn the process in silent mode. We have set up an Ora progress spinner.
-            const { stdout } = yield spawnWithDebugOutput('yarn', ['--silent', 'ng-dev', 'release', 'build', '--json'], { mode: 'silent' });
+            const { stdout } = yield spawn('yarn', ['--silent', 'ng-dev', 'release', 'build', '--json'], { mode: 'silent' });
             spinner.stop();
             info(green('  ✓   Built release output for all packages.'));
             // The `ng-dev release build` command prints a JSON array to stdout
@@ -6295,7 +6311,7 @@ function invokeYarnInstallCommand(projectDir) {
         try {
             // Note: No progress indicator needed as that is the responsibility of the command.
             // TODO: Consider using an Ora spinner instead to ensure minimal console output.
-            yield spawnWithDebugOutput('yarn', ['install', '--frozen-lockfile', '--non-interactive'], { cwd: projectDir });
+            yield spawn('yarn', ['install', '--frozen-lockfile', '--non-interactive'], { cwd: projectDir });
             info(green('  ✓   Installed project dependencies.'));
         }
         catch (e) {
@@ -7450,7 +7466,7 @@ class ReleaseTool {
             try {
                 // Note: We do not rely on `/usr/bin/env` but rather access the `env` binary directly as it
                 // should be part of the shell's `$PATH`. This is necessary for compatibility with Windows.
-                const pyVersion = yield spawnWithDebugOutput('env', ['python', '--version'], { mode: 'silent' });
+                const pyVersion = yield spawn('env', ['python', '--version'], { mode: 'silent' });
                 const version = pyVersion.stdout.trim() || pyVersion.stderr.trim();
                 if (version.startsWith('Python 3.')) {
                     debug(`Local python version: ${version}`);
diff --git a/dev-infra/pr/discover-new-conflicts/index.ts b/dev-infra/pr/discover-new-conflicts/index.ts
index b164155566..32138da310 100644
--- a/dev-infra/pr/discover-new-conflicts/index.ts
+++ b/dev-infra/pr/discover-new-conflicts/index.ts
@@ -11,7 +11,7 @@ import {types as graphqlTypes} from 'typed-graphqlify';
 
 import {error, info} from '../../utils/console';
 import {AuthenticatedGitClient} from '../../utils/git/authenticated-git-client';
-import {GitClient} from '../../utils/git/git-client';
+import {GitCommandError} from '../../utils/git/git-client';
 import {getPendingPrs} from '../../utils/github';
 import {exec} from '../../utils/shelljs';
 
@@ -95,16 +95,20 @@ export async function discoverNewConflictsForPr(newPrNumber: number, updatedAfte
   info(`Checking ${pendingPrs.length} PRs for conflicts after a merge of #${newPrNumber}`);
 
   // Fetch and checkout the PR being checked.
-  exec(`git fetch ${requestedPr.headRef.repository.url} ${requestedPr.headRef.name}`);
-  exec(`git checkout -B ${tempWorkingBranch} FETCH_HEAD`);
+  git.run(['fetch', '-q', requestedPr.headRef.repository.url, requestedPr.headRef.name]);
+  git.run(['checkout', '-q', '-B', tempWorkingBranch, 'FETCH_HEAD']);
 
   // Rebase the PR against the PRs target branch.
-  exec(`git fetch ${requestedPr.baseRef.repository.url} ${requestedPr.baseRef.name}`);
-  const result = exec(`git rebase FETCH_HEAD`);
-  if (result.code) {
-    error('The requested PR currently has conflicts');
-    cleanUpGitState(previousBranchOrRevision);
-    process.exit(1);
+  git.run(['fetch', '-q', requestedPr.baseRef.repository.url, requestedPr.baseRef.name]);
+  try {
+    git.run(['rebase', 'FETCH_HEAD'], {stdio: 'ignore'});
+  } catch (err) {
+    if (err instanceof GitCommandError) {
+      error('The requested PR currently has conflicts');
+      git.checkout(previousBranchOrRevision, true);
+      process.exit(1);
+    }
+    throw err;
   }
 
   // Start the progress bar
@@ -113,15 +117,19 @@ export async function discoverNewConflictsForPr(newPrNumber: number, updatedAfte
   // Check each PR to determine if it can merge cleanly into the repo after the target PR.
   for (const pr of pendingPrs) {
     // Fetch and checkout the next PR
-    exec(`git fetch ${pr.headRef.repository.url} ${pr.headRef.name}`);
-    exec(`git checkout --detach FETCH_HEAD`);
+    git.run(['fetch', '-q', pr.headRef.repository.url, pr.headRef.name]);
+    git.run(['checkout', '-q', '--detach', 'FETCH_HEAD']);
     // Check if the PR cleanly rebases into the repo after the target PR.
-    const result = exec(`git rebase ${tempWorkingBranch}`);
-    if (result.code !== 0) {
-      conflicts.push(pr);
+    try {
+      git.run(['rebase', tempWorkingBranch], {stdio: 'ignore'});
+    } catch (err) {
+      if (err instanceof GitCommandError) {
+        conflicts.push(pr);
+      }
+      throw err;
     }
     // Abort any outstanding rebase attempt.
-    exec(`git rebase --abort`);
+    git.runGraceful(['rebase', '--abort'], {stdio: 'ignore'});
 
     progressBar.increment(1);
   }
diff --git a/dev-infra/release/publish/external-commands.ts b/dev-infra/release/publish/external-commands.ts
index 2683e3ce46..f0b9edf366 100644
--- a/dev-infra/release/publish/external-commands.ts
+++ b/dev-infra/release/publish/external-commands.ts
@@ -9,7 +9,7 @@
 import * as ora from 'ora';
 import * as semver from 'semver';
 
-import {spawnWithDebugOutput} from '../../utils/child-process';
+import {spawn} from '../../utils/child-process';
 import {error, green, info, red} from '../../utils/console';
 import {BuiltPackage} from '../config/index';
 import {NpmDistTag} from '../versioning';
@@ -40,7 +40,7 @@ import {FatalReleaseActionError} from './actions-error';
 export async function invokeSetNpmDistCommand(npmDistTag: NpmDistTag, version: semver.SemVer) {
   try {
     // Note: No progress indicator needed as that is the responsibility of the command.
-    await spawnWithDebugOutput(
+    await spawn(
         'yarn', ['--silent', 'ng-dev', 'release', 'set-dist-tag', npmDistTag, version.format()]);
     info(green(`  ✓   Set "${npmDistTag}" NPM dist tag for all packages to v${version}.`));
   } catch (e) {
@@ -59,8 +59,8 @@ export async function invokeReleaseBuildCommand(): Promise<BuiltPackage[]> {
   try {
     // Since we expect JSON to be printed from the `ng-dev release build` command,
     // we spawn the process in silent mode. We have set up an Ora progress spinner.
-    const {stdout} = await spawnWithDebugOutput(
-        'yarn', ['--silent', 'ng-dev', 'release', 'build', '--json'], {mode: 'silent'});
+    const {stdout} =
+        await spawn('yarn', ['--silent', 'ng-dev', 'release', 'build', '--json'], {mode: 'silent'});
     spinner.stop();
     info(green('  ✓   Built release output for all packages.'));
     // The `ng-dev release build` command prints a JSON array to stdout
@@ -82,8 +82,7 @@ export async function invokeYarnInstallCommand(projectDir: string): Promise<void
   try {
     // Note: No progress indicator needed as that is the responsibility of the command.
     // TODO: Consider using an Ora spinner instead to ensure minimal console output.
-    await spawnWithDebugOutput(
-        'yarn', ['install', '--frozen-lockfile', '--non-interactive'], {cwd: projectDir});
+    await spawn('yarn', ['install', '--frozen-lockfile', '--non-interactive'], {cwd: projectDir});
     info(green('  ✓   Installed project dependencies.'));
   } catch (e) {
     error(e);
diff --git a/dev-infra/release/publish/index.ts b/dev-infra/release/publish/index.ts
index ac4b5255e2..830bd38f35 100644
--- a/dev-infra/release/publish/index.ts
+++ b/dev-infra/release/publish/index.ts
@@ -8,7 +8,7 @@
 
 import {ListChoiceOptions, prompt} from 'inquirer';
 
-import {spawnWithDebugOutput} from '../../utils/child-process';
+import {spawn} from '../../utils/child-process';
 import {GithubConfig} from '../../utils/config';
 import {debug, error, info, log, promptConfirm, red, yellow} from '../../utils/console';
 import {AuthenticatedGitClient} from '../../utils/git/authenticated-git-client';
@@ -138,8 +138,7 @@ export class ReleaseTool {
     try {
       // Note: We do not rely on `/usr/bin/env` but rather access the `env` binary directly as it
       // should be part of the shell's `$PATH`. This is necessary for compatibility with Windows.
-      const pyVersion =
-          await spawnWithDebugOutput('env', ['python', '--version'], {mode: 'silent'});
+      const pyVersion = await spawn('env', ['python', '--version'], {mode: 'silent'});
       const version = pyVersion.stdout.trim() || pyVersion.stderr.trim();
       if (version.startsWith('Python 3.')) {
         debug(`Local python version: ${version}`);
diff --git a/dev-infra/release/versioning/npm-publish.ts b/dev-infra/release/versioning/npm-publish.ts
index 1f31c268a5..248bef824d 100644
--- a/dev-infra/release/versioning/npm-publish.ts
+++ b/dev-infra/release/versioning/npm-publish.ts
@@ -7,7 +7,9 @@
  */
 
 import * as semver from 'semver';
-import {spawnInteractiveCommand, spawnWithDebugOutput} from '../../utils/child-process';
+
+import {spawn, spawnInteractive} from '../../utils/child-process';
+
 import {NpmDistTag} from './npm-registry';
 
 /**
@@ -21,7 +23,7 @@ export async function runNpmPublish(
   if (registryUrl !== undefined) {
     args.push('--registry', registryUrl);
   }
-  await spawnWithDebugOutput('npm', args, {cwd: packagePath, mode: 'silent'});
+  await spawn('npm', args, {cwd: packagePath, mode: 'silent'});
 }
 
 /**
@@ -35,7 +37,7 @@ export async function setNpmTagForPackage(
   if (registryUrl !== undefined) {
     args.push('--registry', registryUrl);
   }
-  await spawnWithDebugOutput('npm', args, {mode: 'silent'});
+  await spawn('npm', args, {mode: 'silent'});
 }
 
 /**
@@ -49,7 +51,7 @@ export async function npmIsLoggedIn(registryUrl: string|undefined): Promise<bool
     args.push('--registry', registryUrl);
   }
   try {
-    await spawnWithDebugOutput('npm', args, {mode: 'silent'});
+    await spawn('npm', args, {mode: 'silent'});
   } catch (e) {
     return false;
   }
@@ -70,7 +72,7 @@ export async function npmLogin(registryUrl: string|undefined) {
   }
   // The login command prompts for username, password and other profile information. Hence
   // the process needs to be interactive (i.e. respecting current TTYs stdin).
-  await spawnInteractiveCommand('npm', args);
+  await spawnInteractive('npm', args);
 }
 
 /**
@@ -86,7 +88,7 @@ export async function npmLogout(registryUrl: string|undefined): Promise<boolean>
     args.splice(1, 0, '--registry', registryUrl);
   }
   try {
-    await spawnWithDebugOutput('npm', args, {mode: 'silent'});
+    await spawn('npm', args, {mode: 'silent'});
   } finally {
     return npmIsLoggedIn(registryUrl);
   }
diff --git a/dev-infra/utils/child-process.ts b/dev-infra/utils/child-process.ts
index 1a1950f3d5..64fcdcb634 100644
--- a/dev-infra/utils/child-process.ts
+++ b/dev-infra/utils/child-process.ts
@@ -6,21 +6,34 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {spawn, SpawnOptions} from 'child_process';
+import {spawn as _spawn, SpawnOptions as _SpawnOptions, spawnSync as _spawnSync, SpawnSyncOptions as _SpawnSyncOptions} from 'child_process';
 import {debug, error} from './console';
 
-/** Interface describing the options for spawning a process. */
-export interface SpawnedProcessOptions extends Omit<SpawnOptions, 'stdio'> {
-  /** Console output mode. Defaults to "enabled". */
-  mode?: 'enabled'|'silent'|'on-error';
+
+export interface SpawnSyncOptions extends Omit<_SpawnSyncOptions, 'shell'|'stdio'> {
+  /** Whether to prevent exit codes being treated as failures. */
+  suppressErrorOnFailingExitCode?: boolean;
 }
 
+/** Interface describing the options for spawning a process. */
+export interface SpawnOptions extends Omit<_SpawnOptions, 'shell'|'stdio'> {
+  /** Console output mode. Defaults to "enabled". */
+  mode?: 'enabled'|'silent'|'on-error';
+  /** Whether to prevent exit codes being treated as failures. */
+  suppressErrorOnFailingExitCode?: boolean;
+}
+
+/** Interface describing the options for spawning an interactive process. */
+export type SpawnInteractiveCommandOptions = Omit<_SpawnOptions, 'shell'|'stdio'>;
+
 /** Interface describing the result of a spawned process. */
-export interface SpawnedProcessResult {
+export interface SpawnResult {
   /** Captured stdout in string format. */
   stdout: string;
   /** Captured stderr in string format. */
   stderr: string;
+  /** The exit code or signal of the process. */
+  status: number|NodeJS.Signals;
 }
 
 /**
@@ -29,12 +42,12 @@ export interface SpawnedProcessResult {
  *
  * @returns a Promise resolving on success, and rejecting on command failure with the status code.
  */
-export function spawnInteractiveCommand(
-    command: string, args: string[], options: Omit<SpawnOptions, 'stdio'> = {}) {
+export function spawnInteractive(
+    command: string, args: string[], options: SpawnInteractiveCommandOptions = {}) {
   return new Promise<void>((resolve, reject) => {
     const commandText = `${command} ${args.join(' ')}`;
     debug(`Executing command: ${commandText}`);
-    const childProcess = spawn(command, args, {...options, shell: true, stdio: 'inherit'});
+    const childProcess = _spawn(command, args, {...options, shell: true, stdio: 'inherit'});
     childProcess.on('exit', status => status === 0 ? resolve() : reject(status));
   });
 }
@@ -45,18 +58,17 @@ export function spawnInteractiveCommand(
  * output mode, stdout/stderr output is also printed to the console, or only on error.
  *
  * @returns a Promise resolving with captured stdout and stderr on success. The promise
- *   rejects on command failure.
+ *   rejects on command failure
  */
-export function spawnWithDebugOutput(
-    command: string, args: string[],
-    options: SpawnedProcessOptions = {}): Promise<SpawnedProcessResult> {
+export function spawn(
+    command: string, args: string[], options: SpawnOptions = {}): Promise<SpawnResult> {
   return new Promise((resolve, reject) => {
     const commandText = `${command} ${args.join(' ')}`;
     const outputMode = options.mode;
 
     debug(`Executing command: ${commandText}`);
 
-    const childProcess = spawn(command, args, {...options, shell: true, stdio: 'pipe'});
+    const childProcess = _spawn(command, args, {...options, shell: true, stdio: 'pipe'});
     let logOutput = '';
     let stdout = '';
     let stderr = '';
@@ -83,20 +95,51 @@ export function spawnWithDebugOutput(
       }
     });
 
-    childProcess.on('exit', (status, signal) => {
-      const exitDescription = status !== null ? `exit code "${status}"` : `signal "${signal}"`;
+    childProcess.on('exit', (exitCode, signal) => {
+      const exitDescription = exitCode !== null ? `exit code "${exitCode}"` : `signal "${signal}"`;
       const printFn = outputMode === 'on-error' ? error : debug;
+      const status = statusFromExitCodeAndSignal(exitCode, signal);
 
       printFn(`Command "${commandText}" completed with ${exitDescription}.`);
       printFn(`Process output: \n${logOutput}`);
 
       // On success, resolve the promise. Otherwise reject with the captured stderr
       // and stdout log output if the output mode was set to `silent`.
-      if (status === 0) {
-        resolve({stdout, stderr});
+      if (status === 0 || options.suppressErrorOnFailingExitCode) {
+        resolve({stdout, stderr, status});
       } else {
         reject(outputMode === 'silent' ? logOutput : undefined);
       }
     });
   });
 }
+
+/**
+ * Spawns a given command with the specified arguments inside a shell syncronously.
+ *
+ * @returns The command's stdout and stderr.
+ */
+export function spawnSync(
+    command: string, args: string[], options: SpawnOptions = {}): SpawnResult {
+  const commandText = `${command} ${args.join(' ')}`;
+  debug(`Executing command: ${commandText}`);
+
+  const {status: exitCode, signal, stdout, stderr} =
+      _spawnSync(command, args, {...options, encoding: 'utf8', shell: true, stdio: 'pipe'});
+
+  /** The status of the spawn result. */
+  const status = statusFromExitCodeAndSignal(exitCode, signal);
+
+  if (status === 0 || options.suppressErrorOnFailingExitCode) {
+    return {status, stdout, stderr};
+  }
+
+  throw new Error(stderr);
+}
+
+
+
+/** Convert the provided exitCode and signal to a single status code. */
+function statusFromExitCodeAndSignal(exitCode: number|null, signal: NodeJS.Signals|null) {
+  return exitCode !== null ? exitCode : signal !== null ? signal : -1;
+}
diff --git a/dev-infra/utils/git/git-client.ts b/dev-infra/utils/git/git-client.ts
index eab11db987..52e803b9a5 100644
--- a/dev-infra/utils/git/git-client.ts
+++ b/dev-infra/utils/git/git-client.ts
@@ -9,7 +9,6 @@
 import {spawnSync, SpawnSyncOptions, SpawnSyncReturns} from 'child_process';
 import {Options as SemVerOptions, parse, SemVer} from 'semver';
 
-import {spawnWithDebugOutput} from '../child-process';
 import {getConfig, GithubConfig, NgDevConfig} from '../config';
 import {debug, info} from '../console';
 import {DryRunError, isDryRun} from '../dry-run';
@@ -24,6 +23,7 @@ export class GitCommandError extends Error {
     // accidentally leak the Github token that might be used in a command,
     // we sanitize the command that will be part of the error message.
     super(`Command failed: git ${client.sanitizeConsoleOutput(args.join(' '))}`);
+    Object.setPrototypeOf(this, GitCommandError.prototype);
   }
 }