feat(ng-dev): add safety checks for shallow repositories (#218)

Adds safety checks for shallow repositories when executing
the merge or release publish script. These two commands
have similar checks on the local repository and these tools
act on the local repository as part of a common development
workflow where an error beforehand would be more useful.

PR Close #218

ng-dev/pr/merge/index.ts

@@ -93,6 +93,11 @@ export async function mergePullRequest(prNumber: number, flags: PullRequestMerge
           ),
         );
         return false;
+      case MergeStatus.UNEXPECTED_SHALLOW_REPO:
+        error(red(`Unable to perform merge in a local repository that is configured as shallow.`));
+        error(red(`Please convert the repository to a complete one by syncing with upstream.`));
+        error(red(`https://git-scm.com/docs/git-fetch#Documentation/git-fetch.txt---unshallow`));
+        return false;
       case MergeStatus.UNKNOWN_GIT_ERROR:
         error(
           red(

ng-dev/pr/merge/task.ts

@@ -24,6 +24,7 @@ import {AutosquashMergeStrategy} from './strategies/autosquash-merge';
 export const enum MergeStatus {
   UNKNOWN_GIT_ERROR,
   DIRTY_WORKING_DIR,
+  UNEXPECTED_SHALLOW_REPO,
   SUCCESS,
   FAILED,
   USER_ABORTED,
@@ -69,6 +70,14 @@ export class PullRequestMergeTask {
    * @param force Whether non-critical pull request failures should be ignored.
    */
   async merge(prNumber: number, force = false): Promise<MergeResult> {
+    if (this.git.hasUncommittedChanges()) {
+      return {status: MergeStatus.DIRTY_WORKING_DIR};
+    }
+
+    if (this.git.isShallowRepo()) {
+      return {status: MergeStatus.UNEXPECTED_SHALLOW_REPO};
+    }
+
     // Check whether the given Github token has sufficient permissions for writing
     // to the configured repository. If the repository is not private, only the
     // reduced `public_repo` OAuth scope is sufficient for performing merges.
@@ -98,10 +107,6 @@ export class PullRequestMergeTask {
       };
     }
 
-    if (this.git.hasUncommittedChanges()) {
-      return {status: MergeStatus.DIRTY_WORKING_DIR};
-    }
-
     const pullRequest = await loadAndValidatePullRequest(this, prNumber, force);
 
     if (!isPullRequest(pullRequest)) {

ng-dev/release/publish/index.ts

@@ -51,7 +51,8 @@ export class ReleaseTool {
 
     if (
       !(await this._verifyNoUncommittedChanges()) ||
-      !(await this._verifyRunningFromNextBranch(nextBranchName))
+      !(await this._verifyRunningFromNextBranch(nextBranchName)) ||
+      !(await this._verifyNoShallowRepository())
     ) {
       return CompletionState.FATAL_ERROR;
     }
@@ -137,6 +138,22 @@ export class ReleaseTool {
     return true;
   }
 
+  /**
+   * Verifies that the local repository is not configured as shallow.
+   * @returns a boolean indicating success or failure.
+   */
+  private async _verifyNoShallowRepository(): Promise<boolean> {
+    if (this._git.isShallowRepo()) {
+      error(red('  ✘   The local repository is configured as shallow.'));
+      error(red(`      Please convert the repository to a complete one by syncing with upstream.`));
+      error(
+        red(`      https://git-scm.com/docs/git-fetch#Documentation/git-fetch.txt---unshallow`),
+      );
+      return false;
+    }
+    return true;
+  }
+
   /**
    * Verifies that the next branch from the configured repository is checked out.
    * @returns a boolean indicating success or failure.

ng-dev/utils/git/git-client.ts

@@ -137,6 +137,11 @@ export class GitClient {
     return this.run(['branch', branchName, '--contains', sha]).stdout !== '';
   }
 
+  /** Whether the local repository is configured as shallow. */
+  isShallowRepo(): boolean {
+    return this.run(['rev-parse', '--is-shallow-repository']).stdout.trim() === 'true';
+  }
+
   /** Gets the currently checked out branch or revision. */
   getCurrentBranchOrRevision(): string {
     const branchName = this.run(['rev-parse', '--abbrev-ref', 'HEAD']).stdout.trim();