Steam downloads: a redistributable's file no longer replaces the game's own copy

app/Madeira/SwiftSteam/Content/DepotDownloader.swift

@@ -439,11 +439,12 @@ final class DepotDownloader {
         // the earlier depot's chunks over the later one's, flipping the file
         // on every repair (Borderlands 2: the same 552 MB on each Repair, and
         // Steam's CEG step ending with 53, DataCorruption). Only the last
-        // depot that lists a path writes it.
+        // depot that lists a path writes it. A redistributable goes to its
+        // owner's folder, so the same name there is another file.
         var lastOwner: [String: Int] = [:]
         for (index, plan) in plans.enumerated() {
             for file in plan.manifest.files where !file.isDirectory && file.flags & 0x200 == 0 {
-                lastOwner[Self.overlapKey(file.filename)] = index
+                lastOwner[Self.overlapKey(file.filename, in: plan.installURL)] = index
             }
         }
         var overridden = 0
@@ -458,7 +459,7 @@ final class DepotDownloader {
             for (fileIndex, file) in plan.manifest.files.enumerated() {
                 // A later depot lists this file too: its copy is the one installed.
                 if !file.isDirectory, file.flags & 0x200 == 0,
-                   let owner = lastOwner[Self.overlapKey(file.filename)], owner != planIndex {
+                   let owner = lastOwner[Self.overlapKey(file.filename, in: plan.installURL)], owner != planIndex {
                     overridden += 1
                     paths.append(""); existing.append(false); continue
                 }
@@ -514,9 +515,9 @@ final class DepotDownloader {
         return result
     }
 
-    /// One install path, compared as Windows compares names: any case, either slash.
-    private nonisolated static func overlapKey(_ filename: String) -> String {
-        filename.replacingOccurrences(of: "\\", with: "/").lowercased()
+    /// One install path in one folder, compared as Windows compares names: any case, either slash.
+    private nonisolated static func overlapKey(_ filename: String, in folder: URL) -> String {
+        folder.path + "\n" + filename.replacingOccurrences(of: "\\", with: "/").lowercased()
     }
 
     /// Create or resize a file to its manifest length. Existing bytes below

tests/host/check-depot-overlap.py

@@ -10,7 +10,9 @@
     (empty path, no pending chunks) and kept by B;
   - files only one depot lists, and directories, are untouched (a directory's
     path entry is empty by design: it has no chunks);
-  - one depot alone is unchanged.
+  - one depot alone is unchanged;
+  - a redistributable in its owner's folder and a game depot that list the
+    same name each write their own copy, in their own folder.
 Needs swiftc (SWIFTC=wrapper, see the host-tests notes) and python3.
 """
 from pathlib import Path
@@ -70,13 +72,13 @@ def block(text, signature):
         try! FileManager.default.createDirectory(at: jdir, withIntermediateDirectories: true)
         func chunk() -> DepotManifest.ChunkEntry { .init(sha: Data(count: 20), crc: 0, offset: 0, compressedSize: 8, uncompressedSize: 16) }
         func file(_ n: String, dir: Bool = false) -> DepotManifest.FileEntry { .init(filename: n, size: dir ? 0 : 16, flags: dir ? 0x40 : 0, chunks: dir ? [] : [chunk()]) }
-        func plan(_ id: UInt32, _ files: [DepotManifest.FileEntry]) -> DepotPlan {
+        func plan(_ id: UInt32, _ files: [DepotManifest.FileEntry], into folder: URL? = nil) -> DepotPlan {
             DepotPlan(depotID: id, manifestGID: UInt64(id), key: Data(), manifest: .init(files: files), hosts: [], auth: [:],
-                      declaredSize: 0, health: ContentHostHealth())
+                      declaredSize: 0, health: ContentHostHealth(), installURL: folder ?? game)
         }
         let a = plan(1, [file("Binaries", dir: true), file("Binaries\\Win32\\Game.exe"), file("WillowGame/CookedPCConsole/a.upk"), file("only-a.txt")])
         let b = plan(2, [file("binaries/win32/game.EXE"), file("WillowGame\\CookedPCConsole\\A.upk"), file("only-b.txt")])
-        let p = try! prepare(plans: [a, b], installURL: game, journalDir: jdir)
+        let p = try! prepare(plans: [a, b], journalDir: jdir)
         var fails = 0
         func check(_ ok: Bool, _ what: String) { if !ok { print("FAIL: \(what)"); fails += 1 } }
         check(p.paths[0][1] == "" && p.paths[0][2] == "", "depot A still writes the shared files: \(p.paths[0])")
@@ -86,8 +88,19 @@ def block(text, signature):
         check(p.paths[1].allSatisfy { !$0.isEmpty }, "depot B lost a file: \(p.paths[1])")
         check(Set(p.pending[0].map(\.file)) == [3], "depot A pending chunks: \(p.pending[0].map(\.file))")
         check(Set(p.pending[1].map(\.file)) == [0, 1, 2], "depot B pending chunks: \(p.pending[1].map(\.file))")
-        let solo = try! prepare(plans: [a], installURL: game, journalDir: jdir)
+        let solo = try! prepare(plans: [a], journalDir: jdir)
         check(solo.paths[0].dropFirst().allSatisfy { !$0.isEmpty }, "a lone depot skipped files: \(solo.paths[0])")
+        // A redistributable goes to its owner's folder (Steamworks Shared), planned after the game's depots.
+        let shared = dir.appendingPathComponent("Steamworks Shared")
+        let own = plan(5, [file("_CommonRedist/vcredist/2019/VC_redist.x64.exe"), file("Game.exe")])
+        let redist = plan(6, [file("_CommonRedist\\vcredist\\2019\\VC_redist.x64.exe")], into: shared)
+        let two = try! prepare(plans: [own, redist], journalDir: jdir)
+        check(two.paths[0][0] == game.appendingPathComponent("_CommonRedist/vcredist/2019/VC_redist.x64.exe").path,
+              "the game's own copy is not written to its folder: \(two.paths[0])")
+        check(two.paths[1][0] == shared.appendingPathComponent("_CommonRedist/vcredist/2019/VC_redist.x64.exe").path,
+              "the redistributable's copy is not written to its owner's folder: \(two.paths[1])")
+        check(Set(two.pending[0].map(\.file)) == [0, 1] && Set(two.pending[1].map(\.file)) == [0],
+              "pending chunks across two folders: \(two.pending.map { $0.map(\.file) })")
         return fails == 0 ? 0 : 1
     }
 }
@@ -102,5 +115,6 @@ def block(text, signature):
     assert r.returncode == 0, r.stdout + r.stderr
     r = subprocess.run([str(folder / 'check')], capture_output=True, text=True)
     assert r.returncode == 0, r.stdout + r.stderr
-    assert '[steam-depot] overlap files=2' in r.stdout, r.stdout
-print('PASS: a file two depots list is written only by the later depot (any case, either slash); other files untouched')
+    assert '[steam-depot] overlap files=2' in r.stdout and 'overlap files=1' not in r.stdout, r.stdout
+print('PASS: a file two depots list is written only by the later depot (any case, either slash); other files untouched; '
+      'a redistributable in its owner\'s folder does not replace the game\'s own copy')