From bc7500bde97cdbbe7e6df98700622e1e47468528 Mon Sep 17 00:00:00 2001
From: Shadowfacts <me@shadowfacts.net>
Date: Fri, 10 Nov 2023 14:08:11 -0500
Subject: [PATCH] Fix crash when uploading attachment without known MIME type
 or extension

---
 .../Sources/ComposeUI/API/PostService.swift   | 30 ++++++++++++-------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/Packages/ComposeUI/Sources/ComposeUI/API/PostService.swift b/Packages/ComposeUI/Sources/ComposeUI/API/PostService.swift
index 6733c17df2..c7de164d69 100644
--- a/Packages/ComposeUI/Sources/ComposeUI/API/PostService.swift
+++ b/Packages/ComposeUI/Sources/ComposeUI/API/PostService.swift
@@ -114,13 +114,9 @@ class PostService: ObservableObject {
             } catch let error as DraftAttachment.ExportError {
                 throw Error.attachmentData(index: index, cause: error)
             }
-            do {
-                let uploaded = try await uploadAttachment(data: data, utType: utType, description: attachment.attachmentDescription)
-                attachments.append(uploaded.id)
-                currentStep += 1
-            } catch let error as Client.Error {
-                throw Error.attachmentUpload(index: index, cause: error)
-            }
+            let uploaded = try await uploadAttachment(index: index, data: data, utType: utType, description: attachment.attachmentDescription)
+            attachments.append(uploaded.id)
+            currentStep += 1
         }
         return attachments
     }
@@ -138,10 +134,21 @@ class PostService: ObservableObject {
         }
     }
     
-    private func uploadAttachment(data: Data, utType: UTType, description: String?) async throws -> Attachment {
-        let formAttachment = FormAttachment(mimeType: utType.preferredMIMEType!, data: data, fileName: "file.\(utType.preferredFilenameExtension!)")
+    private func uploadAttachment(index: Int, data: Data, utType: UTType, description: String?) async throws -> Attachment {
+        guard let mimeType = utType.preferredMIMEType else {
+            throw Error.attachmentMissingMimeType(index: index, type: utType)
+        }
+        var filename = "file"
+        if let ext = utType.preferredFilenameExtension {
+            filename.append(".\(ext)")
+        }
+        let formAttachment = FormAttachment(mimeType: mimeType, data: data, fileName: filename)
         let req = Client.upload(attachment: formAttachment, description: description)
-        return try await mastodonController.run(req).0
+        do {
+            return try await mastodonController.run(req).0
+        } catch let error as Client.Error {
+            throw Error.attachmentUpload(index: index, cause: error)
+        }
     }
     
     private func textForPosting() -> String {
@@ -170,6 +177,7 @@ class PostService: ObservableObject {
     
     enum Error: Swift.Error, LocalizedError {
         case attachmentData(index: Int, cause: DraftAttachment.ExportError)
+        case attachmentMissingMimeType(index: Int, type: UTType)
         case attachmentUpload(index: Int, cause: Client.Error)
         case posting(Client.Error)
         
@@ -177,6 +185,8 @@ class PostService: ObservableObject {
             switch self {
             case let .attachmentData(index: index, cause: cause):
                 return "Attachment \(index + 1): \(cause.localizedDescription)"
+            case let .attachmentMissingMimeType(index: index, type: type):
+                return "Attachment \(index + 1): unknown MIME type for \(type.identifier)"
             case let .attachmentUpload(index: index, cause: cause):
                 return "Attachment \(index + 1): \(cause.localizedDescription)"
             case let .posting(error):