[Error] [UriError]: cannot call joinPath on URI without path — textFileService

[vs-code-engineering]

Error Message

unhandlederror-[UriError]: cannot call joinPath on URI without path

Stack Trace

    at a.joinPath (./src/vs/base/common/uri.ts:362:9)
    at ele.joinPath (./src/vs/base/common/resources.ts:186:13)
    at joinPath (./src/vs/workbench/services/textfile/browser/textFileService.ts:813:0)
    at ght.getDefaultEncodingOverrides (./src/vs/workbench/services/textfile/browser/textFileService.ts:812:0)
    at cye.value (./src/vs/workbench/services/textfile/browser/textFileService.ts:798:0)
    at E._deliver (./src/vs/base/common/event.ts:1354:12)
    at E._deliverQueue (./src/vs/base/common/event.ts:1365:8)
    at E.fire (./src/vs/base/common/event.ts:1389:8)
    at pXt._doUpdateFolders (./src/vs/sessions/services/workspace/browser/workspaceContextService.ts:163:36)

Raw Stack Trace (minified)

Error: [UriError]: cannot call joinPath on URI without path     at a.joinPath (out/vs/sessions/sessions.desktop.main.js:406:59221)     at ele.joinPath (out/vs/sessions/sessions.desktop.main.js:406:68517)     at out/vs/sessions/sessions.desktop.main.js:4554:20843     at Array.forEach (<anonymous>)     at ght.getDefaultEncodingOverrides (out/vs/sessions/sessions.desktop.main.js:4554:20816)     at cye.value (out/vs/sessions/sessions.desktop.main.js:4554:20511)     at E._deliver (out/vs/sessions/sessions.desktop.main.js:405:3066)     at E._deliverQueue (out/vs/sessions/sessions.desktop.main.js:405:3155)     at E.fire (out/vs/sessions/sessions.desktop.main.js:405:3490)     at pXt._doUpdateFolders (out/vs/sessions/sessions.desktop.main.js:4549:2992)

Details

Property	Value
Bucket ID	420aa826-5262-5f6c-5396-814b3c17f7b3
Version	1.115.0-insider
Commit	41dd792b
Last Seen	Tue Apr 14 2026 17:59:52 GMT+0000 (Coordinated Universal Time)
Platforms	Windows, Linux, Mac
Product	Agents

---

This issue was automatically created from the VS Code Errors Dashboard

[vs-code-engineering]

🔍 Error Investigation

Summary

The error [UriError]: cannot call joinPath on URI without path occurs in the Agents product when a session has no repository metadata. The _buildWorkspace() method in copilotChatSessionsProvider.ts creates a fallback URI URI.parse('unknown:') which has no path component. When workspace folders change, textFileService.ts calls joinPath(folder.uri, '.vscode') on every folder URI, and this path-less URI causes the throw. This is a persistent issue across versions 1.114–1.116 affecting ~1,600+ users cumulatively.

Culprit Commit

Field	Value
Commit	f62d4324 (via PR #309777)
Author	@aeschli
PR	#309777
Message	Empty sessions view: cannot call joinPath
Why	This PR changed URI.parse('unknown://') to URI.parse('unknown:') and improved the error message, but both URIs have empty paths — the fix was incomplete. The original unknown:// fallback was introduced earlier when _buildWorkspace was created. The PR author noted: "Maybe you want to revisit unknown:///" — suggesting the proper fix was not applied.

Note: The error existed before PR #309777 as well (since at least March 27, 2026). The original URI.parse('unknown://') also has no path. PR #309777 was an incomplete fix attempt.

Code Flow

sequenceDiagram
    participant WFM as WorkspaceFolderManagement
    participant WCS as SessionsWorkspaceContextService
    participant TFS as TextFileService
    participant URI as URI.joinPath

    WFM->>WFM: updateWorkspaceFoldersForSession()
    Note over WFM: Session has no repo metadata<br/>→ getActiveSessionFolderData()<br/>returns uri: URI.parse('unknown:')
    WFM->>WCS: addFolders([{uri: unknown:}])
    WCS->>WCS: _doUpdateFolders()
    WCS->>TFS: fire onDidChangeWorkspaceFolders
    TFS->>TFS: getDefaultEncodingOverrides()
    loop Each workspace folder
        TFS->>URI: joinPath(folder.uri, '.vscode')
        Note over URI: ⚠️ folder.uri.path is ''<br/>(empty = falsy)
        URI-->>TFS: 💥 throw [UriError]:<br/>cannot call joinPath on<br/>URI without path
    end

Loading

Affected Files

File	Role
src/vs/sessions/contrib/copilotChatSessions/browser/copilotChatSessionsProvider.ts	Root cause — _buildWorkspace() line 978 creates URI.parse('unknown:') with no path
src/vs/sessions/contrib/workspace/browser/workspaceFolderManagement.ts	Data flow — passes the path-less URI as a workspace folder
src/vs/workbench/services/textfile/browser/textFileService.ts	Crash site — getDefaultEncodingOverrides() line 813 calls joinPath(folder.uri, '.vscode')
src/vs/base/common/uri.ts	Error thrown at URI.joinPath() line 362 when uri.path is falsy

Related Issues

• [Unhandled Error] [UriError]: cannot call joinPath on URI without path — workspaceExtensionsConfig / mcpToolRegistration #308827 — Same root cause (unknown: URI with no path), different crash site (workspaceExtensionsConfig.ts / mcpToolRegistration). Already assigned to @sandy081.

Repro Steps

1. Open VS Code Agents (sessions desktop)
2. Create or switch to a session that has no repository metadata (e.g., an empty/new session without a configured repository)
3. The workspace folder management adds a folder with URI unknown: (no path)
4. Any code listening to onDidChangeWorkspaceFolders that calls joinPath on the folder URI will throw

The error is triggered automatically when workspace folders update — no explicit user action beyond having a session without repo metadata is required.

Fix Proposal

Primary fix location: src/vs/sessions/contrib/copilotChatSessions/browser/copilotChatSessionsProvider.ts → _buildWorkspace()

Option A (preferred): When repoUri is undefined, do not create a workspace at all — return undefined from _buildWorkspace() instead of using a meaningless unknown: fallback. The downstream code in workspaceFolderManagement.ts already handles undefined workspace data (lines 45-49).

Option B (minimal): Change URI.parse('unknown:') to URI.parse('unknown:///') which includes a root path /. This prevents the joinPath error but leaves a non-resolvable URI as a workspace folder, which may cause other issues (as @aeschli noted in PR #309777).

Option C (defensive): Add a guard in textFileService.ts → getDefaultEncodingOverrides() to skip folders whose URIs have no path: if (folder.uri.path) { ... }. This protects against any path-less URI but only addresses this one call site — other listeners (like #308827's workspaceExtensionsConfig.ts) would still crash.

Recommended Owner

@sandy081 — Already assigned to the sibling issue #308827 (same root cause, different crash site) and is the primary author of the sessions workspace management code (PR #298395, multiple copilotChatSessionsProvider.ts changes).

Generated by errors-investigate · ● 10.1M · ◷