[laurentiu021]

The Left behind card stays on the Uninstaller until it is dismissed, so between finding what an uninstall left and pressing Remove ticked… the app can be installed again, or another app into one of the listed folders. The removal re-checked each folder's location and links and nothing else, so it could send a freshly installed app's folder, its AppData folder and its settings key to the Recycle Bin or delete them. The pending list read back in an administrator session already applied the full rules; the same-session removal now does too.

What changes

• LeftoverService.RemoveAsync reads the uninstall entries Windows holds once per removal, and every folder and key is held to the search's rules again before it goes: refused when an installed app lives in it, inside it or around it (SharedWith), when it was left by an app whose name is registered again, and, for what was found by a name, when an installed app answers to that name (IsShared, by the publisher for a Guess). While that list cannot be read whole, nothing found by a name is removed, as in the search; the install folder came from the app's own entry and is held to the rules that need no name. Each refusal is one sentence on the status line, like the others.
• LeftoverItem.AppName records which app left each item, set by the search and by the pending list.
• SafeWalkOptions.Unreadable collects the folders the walk could not list. MeasureFolder reports whether it listed everything and throws when its token was cancelled, instead of reading an unfinished walk as "no link inside". A folder it could not look through whole is not offered by the search, not removed, and not offered again from the pending list.
• The once-per-folder refusal in LeftoverFinder.AddFolder is kept by path. Matching the start of the sentences already written also matched a sibling such as Acme after Acme Notes, whose refusal was then never shown.
• README: the removal checks every item again against the same rules and what is installed by then.

How it was checked

Each new test was run against the code with its rule taken out, and failed for that reason:

• Without the re-check in RemoveFolder, AFolderAnAppWasInstalledIntoSinceTheSearch_IsNotRemoved, AFolderFoundByItsName_IsNotRemoved_OnceAnInstalledAppAnswersToThatName, APublisherFolder_IsNotRemoved_OnceAnotherAppOfThatPublisherIsInstalled, WhatAnAppInstalledAgainLeft_IsKept_FolderAndKeyAlike and WhileTheUninstallListCannotBeReadWhole_OnlyTheInstallFolderCanGo failed. Taking out only the name-registered-again rule, only the key's re-check, or only the incomplete-list rule failed the tests for that rule.
• Without the cancellation check after the walk, CancelledWhileAFolderIsCheckedAgain_TheFolderStays sent a folder holding a junction to the recorder standing in for the Recycle Bin. The token is cancelled from inside the location check, so the walk sees it before its first folder.
• With the walk's verdict forced to "whole", AFolderWithAFolderInsideThatCannotBeOpened_IsNotRemoved and Find_DoesNotOfferAFolderItCouldNotLookThroughWhole failed; without the walk recording unreadable folders, the two SafeFileWalkTests cases failed too. The unopenable folder's name ends in a dot, made through a \\?\ path, so an ordinary path cannot list it whatever the account's privileges; a deny entry would not do, since the walk opens folders with backup semantics and an elevated run passes it by.
• With the old prefix match back, AFolderWhoseNameStartsAnotherRefusedOne_HasItsOwnRefusalShown failed while AFolderRefusedAsTheInstallFolder_IsMentionedOnce_WhenItsNameFindsItAgain still passed. Without AppName set by the search, EveryItem_SaysWhichAppLeftIt failed.
• Unit suite twice, the format check, and all four projects built with no warnings.