Add Discard changes button to the Agent Changes view

[anderson-joyle]

Summary

Adds a Discard changes button (arrow-back $(discard) icon) to the Agent Changes view title bar. After a modal confirmation, it restores the selected agent's local workspace to its last-synced baseline through a local-only, projection-aware Sync/LSP operation.

Resolves #343.

Behavior

• Enabled only when local changes exist and no sync is running: mcs.agentChangesView.hasLocalChanges && !mcs.isSyncing.
• Prompts for the agent when multiple workspaces are connected, then shows a modal confirmation with the local-change count.
• Surfaces picker cancellation as a warning and the absence of connected workspaces as an error, consistent with the existing sync commands.
• Recomputes local changes from disk before discarding them rather than trusting stale tree state.
• Locally created component files are deleted; locally updated or deleted text resources are restored from .mcs/botdefinition.json.
• Handles projection-specific resources safely:
  • edits only the affected entries in shared references.mcs.yml;
  • restores both workflow.json and metadata.yml for deleted workflows;
  • restores per-reference CLI infrastructure/connections/*.sync.yaml files;
  • recreates missing parent directories.
• Binary resources that cannot be reconstructed from the cache are skipped and reported so they can be restored with Get.
• Returns the remaining local changes from the same LSP request and updates the Agent Changes tree directly. Failures are propagated so existing tree state is not replaced with an empty result.

Design

• WorkspaceSynchronizer.DiscardLocalChanges owns cache restoration and projection-aware file handling in the shared Sync layer.
• powerplatformls/discardLocalChanges is a local-only LSP endpoint that reads the current workspace, computes changes, applies the discard, and returns any unresolved changes.
• Local change calculation no longer requires access tokens, Dataverse client setup, or workflow enrichment calls.
• The TypeScript command is orchestration-only: workspace selection, confirmation, busy state/progress, LSP invocation, result reporting, and tree replacement.
• Agent names, skipped paths, and command errors remain PII-tagged for telemetry. Non-Error rejections retain useful text through the repository-standard String(error) fallback.

Key files

Area	Change
src/CopilotStudio.Sync/WorkspaceSynchronizer.cs	Local-only diff and projection-aware discard implementation
src/CopilotStudio.Sync/IWorkspaceSynchronizer.cs, Models.cs	Discard API and result contracts
src/CopilotStudio.Sync.UnitTests/DiscardLocalChangesTests.cs	Shared references, workflows, CLI references, missing parents, malformed manifests, binary skips, and partial-failure coverage
src/LanguageServers/PowerPlatformLS/Impl.PullAgent/DiscardLocalChangesHandler.cs	New local-only discard endpoint
client/src/commands/discardChanges.ts	Command orchestration, user feedback, and telemetry-safe reporting
client/src/sync/workspaceScm.ts	Credential-free local diff requests, propagated failures, and direct local-state replacement
client/src/sync/discardChanges.ts	Removed; restoration now belongs to the projection-aware Sync layer

Testing

• Full .NET Debug build: 0 warnings / 0 errors
• Full .NET traversal: 1,485 passed / 0 failed / 9 skipped (external E2E scenarios)
• Extension host tests: 156 passed / 0 failed
• TypeScript type-check and ESLint pass as part of the host-test pretest flow

Known limitation

• Newly added knowledge attachments are not fully discarded yet: the generated metadata change can be removed while the payload remains on disk. This is intentionally deferred to a follow-up.
• A live F5 smoke test against a real cloned agent has not been completed.

[Copilot]

Pull request overview

Adds an offline “Discard changes” command to the Agent Changes view, enabling users to revert an agent workspace’s local edits back to the last-synced baseline using the LSP cached-file API.

Changes:

• Adds a new title-bar command (microsoft-copilot-studio.discardChanges) and menu contribution for the Agent Changes view.
• Implements discard logic in a dependency-injected module (discardLocalChanges) plus command wiring (confirmation, progress, busy state, refresh).
• Adds host tests covering restorable vs non-restorable changes and batch behavior; adds a helper to recompute local changes after discard.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/vscode-extensions/microsoft-powerplatformlang-extension/package.json	Adds the Discard Changes command + Agent Changes title-bar button contribution.
src/vscode-extensions/microsoft-powerplatformlang-extension/client/src/tests/host/discardChanges.test.ts	New host tests for restorable checks and discard batch behavior.
src/vscode-extensions/microsoft-powerplatformlang-extension/client/src/sync/workspaceScm.ts	Adds refreshLocalChanges() to refresh the tree/badge after discard.
src/vscode-extensions/microsoft-powerplatformlang-extension/client/src/sync/discardChanges.ts	New pure discard/revert logic with restorable filtering and skip reporting.
src/vscode-extensions/microsoft-powerplatformlang-extension/client/src/extension.ts	Registers the new discard command during activation.
src/vscode-extensions/microsoft-powerplatformlang-extension/client/src/commands/discardChanges.ts	New command wiring: workspace selection, confirmation, LSP cache reads, file writes/deletes, and result reporting.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

src/vscode-extensions/microsoft-powerplatformlang-extension/client/src/commands/discardChanges.ts:116

• DiscardDependencies.writeFile is documented as creating parent directories as needed, but the concrete implementation here calls workspace.fs.writeFile directly. If the user deleted a directory along with a file (or a deleted file lives under a now-missing folder), restore will fail and the change will be skipped unnecessarily. Create the parent directory before writing.

            writeFile: async (uri: Uri, content: string) => {
              await VSworkspace.fs.writeFile(uri, Buffer.from(content, 'utf8'));
            },

[Copilot]

Pull request overview

Copilot reviewed 19 out of 19 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

src/vscode-extensions/microsoft-powerplatformlang-extension/client/src/commands/discardChanges.ts:56

• When no workspace is resolved, logWarning is called with message passed only via the telemetry data object. This means no warning is shown in the VS Code UI (logger only shows UI messages when the message argument is provided), so the command silently does nothing from the user's perspective.

      if (!selectedWorkspace) {
        const message = getAllWorkspaces().length > 0
          ? `No workspace selected. ${DISCARD_OPERATION} operation cancelled.`
          : `No workspace found for ${DISCARD_OPERATION} operation`;
        logger.logWarning(TelemetryEventsKeys.SyncWorkspaceCancel, undefined, { message });

[Copilot]

Pull request overview

Copilot reviewed 19 out of 19 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (2)

src/vscode-extensions/microsoft-powerplatformlang-extension/client/src/commands/discardChanges.ts:57

• When no workspace is resolved, the command logs with message only in the telemetry data object (logWarning(..., undefined, { message })). Since logger only shows a VS Code UI notification when the message parameter is provided, this results in no user-visible feedback. Also, this differs from the existing sync commands, which treat "no workspace found" as an error and "no workspace selected" as a cancel with a visible message.

      if (!selectedWorkspace) {
        const message = getAllWorkspaces().length > 0
          ? `No workspace selected. ${DISCARD_OPERATION} operation cancelled.`
          : `No workspace found for ${DISCARD_OPERATION} operation`;
        logger.logWarning(TelemetryEventsKeys.SyncWorkspaceCancel, undefined, { message });
        return;

src/CopilotStudio.Sync/WorkspaceSynchronizer.cs:4256

• DiscardSkippedChange.Path is currently populated with Path.GetFileName(change.Uri), which drops the relative directory (e.g., knowledge/files/foo.pdf becomes just foo.pdf). The VS Code command surfaces skipped items to the user so they can restore them with Get; without the relative path this can be ambiguous and harder to locate (and loses context for similarly-named files).

    private static DiscardSkippedChange CreateDiscardSkippedChange(Change change, string reason) => new()
    {
        SchemaName = change.SchemaName,
        Path = Path.GetFileName(change.Uri),
        Reason = reason,
    };

[Copilot]

Pull request overview

Copilot reviewed 19 out of 19 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (2)

src/CopilotStudio.Sync/WorkspaceSynchronizer.cs:4256

• CreateDiscardSkippedChange reports Path as Path.GetFileName(change.Uri), which drops the relative directory. This makes the user-facing skipped-items list ambiguous (e.g., multiple workflow.json / metadata.yml files under different workflow folders) and harder to act on when the warning says the items can be restored with Get.

    private static DiscardSkippedChange CreateDiscardSkippedChange(Change change, string reason) => new()
    {
        SchemaName = change.SchemaName,
        Path = Path.GetFileName(change.Uri),
        Reason = reason,
    };

src/vscode-extensions/microsoft-powerplatformlang-extension/client/src/tests/host/discardChanges.test.ts:22

• The PR description lists a new pure module client/src/sync/discardChanges.ts and "12 unit tests" in this host test file, but the branch only contains client/src/commands/discardChanges.ts and this test file currently has 2 formatting/PII tests. Please either update the PR description to match the actual implementation/testing, or add the missing module/tests if they were intended.

import * as assert from 'node:assert';
import { describe, test } from 'node:test';

import { formatDiscardErrorMessage, formatDiscardResultMessage } from '../../commands/discardChanges';

describe('discardChanges: telemetry', () => {
	test('agent names are marked as PII while remaining visible to the user', () => {
		const message = formatDiscardResultMessage('Contoso Support', {
			restored: 1,
			deleted: 0,
			skipped: [],
		});

		assert.match(message, /<pii>Contoso Support<\/pii>/);
	});

	test('non-Error rejections retain their message and PII protection', () => {
		const message = formatDiscardErrorMessage('request rejected');

		assert.match(message, /<pii>request rejected<\/pii>/);
	});
});

[Copilot]

Pull request overview

Copilot reviewed 19 out of 19 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

src/CopilotStudio.Sync/WorkspaceSynchronizer.cs:4256

• DiscardLocalChanges reports skipped items with Path = Path.GetFileName(change.Uri), which drops the relative directory (e.g. infrastructure/connections/foo.sync.yaml becomes foo.sync.yaml). This makes the user-facing message ambiguous and less actionable, especially when multiple files share a name across folders. Use the full relative change.Uri instead.

    private static DiscardSkippedChange CreateDiscardSkippedChange(Change change, string reason) => new()
    {
        SchemaName = change.SchemaName,
        Path = Path.GetFileName(change.Uri),
        Reason = reason,
    };