feat(recorder): Play a replay file from the command line

[bobtista]

• Closes Allow -loadsave and -loadreplay to load files from any directory #3078

-replay already plays visually when used without -headless, but it enters the replay-simulation workflow before the normal shell is shown and terminates the process when that workflow finishes. This is appropriate for batch simulation and synchronization checking, but not for an operating-system file handler whose playback should return to the menus.

-loadreplay <file> instead plays one replay through the normal client lifecycle. loadQueuedReplay runs at the point -loadsave already uses, once the client has initialized the shell, so the menus the playback returns to are on the stack.

Absolute paths are opened in place while relative names still resolve from the Replay directory. RecorderClass::getReplayPathForRead does that, mirroring GameState::getSaveGamePathForRead from #3226. Because this resolution is shared, existing -replay also gains support for absolute paths and no longer requires the .rep extension.

A replay that cannot be read, or whose map is unavailable, is rejected up front with the same message boxes the Replay menu shows, and the game stays on the main menu rather than failing deep in map loading.

Verified with failing files as controls so a pass is distinguishable from "the game started anyway":

case	result
control: bogus absolute path	"REPLAY CANNOT BE LOADED" on the main menu
control: file that is not a replay	"REPLAY CANNOT BE LOADED" on the main menu
control: replay whose map is not installed	"MAP NOT FOUND" on the main menu
Replay from an absolute path containing spaces (quoted)	loads and plays
Relative Replay filename	loads from the managed directory
Replay from a UNC path (\\localhost\C$\...)	loads
Restarting a Replay loaded from an absolute path	restarts and replays from the beginning
Normal Replay synchronization reporting	reports and pauses (InGame:D9C721A5 Replay:D8A198C0 Frame:110)

Todo:

• Both games build (z_generals and g_generals)
• Replay paths outside the user data directory
• Paths containing spaces
• Windows drive paths and UNC paths
• Relative Replay filenames still resolve from the managed directory
• Restarting an externally loaded Replay
• Normal Replay synchronization reporting is unchanged
• Replicate to Generals

[qodo-free-for-open-source-projects]

PR Summary by Qodo

Add visual replay playback and absolute file loading to CLI

✨ Enhancement 🕐 40+ Minutes

AI Description

• Adds -loadreplay to launch visual replay playback after client shell initialization.
• Supports absolute replay and save paths while preserving managed-directory resolution for relative
 names.
• Rejects unreadable, malformed, or map-missing replays before entering gameplay.

Diagram

graph TD
  CLI["CLI parser"] --> Queue["Startup request"] --> Client["Client update"] --> Loader["Replay loader"] --> Resolver["Path resolver"] --> Check{"Replay valid?"}
  Check -->|Yes| Playback["Visual playback"]
  Check -->|No| Quit["Quit game"]

Loading

High-Level Assessment

The queued startup approach is appropriate because it reuses the established -loadsave lifecycle point, ensuring the client shell exists before playback and remains available afterward. Starting playback directly during command-line parsing was considered but would run before required client and filesystem state is initialized; centralizing absolute-versus-relative path resolution also preserves existing menu behavior.

Files changed (15) +214 / -18

Enhancement (15) +214 / -18

FileSystem.hExpose platform-aware absolute path detection +1/-0

Expose platform-aware absolute path detection

• Declares a shared helper for distinguishing explicit absolute paths from names resolved within managed directories.

Core/GameEngine/Include/Common/FileSystem.h

CommandLine.cppAdd and validate startup file-loading options +34/-2

Add and validate startup file-loading options

• Adds the '-loadreplay' parser and registration, validates replay and save extensions, and queues startup playback while suppressing intro and shell-map startup. Missing arguments now consume only the option itself.

Core/GameEngine/Source/Common/CommandLine.cpp

FileSystem.cppImplement cross-platform absolute path recognition +25/-0

Implement cross-platform absolute path recognition

• Recognizes Windows drive-rooted, current-drive-rooted, and UNC-style paths, plus POSIX root paths.

Core/GameEngine/Source/Common/System/FileSystem.cpp

GameState.hDeclare save read-path resolution helper +1/-0

Declare save read-path resolution helper

• Adds the Generals API for resolving absolute save paths or managed-directory filenames.

Generals/Code/GameEngine/Include/Common/GameState.h

GlobalData.hStore queued replay startup requests +1/-0

Store queued replay startup requests

• Adds global startup state for the replay requested through '-loadreplay'.

Generals/Code/GameEngine/Include/Common/GlobalData.h

Recorder.hExpose queued replay loading +1/-0

Expose queued replay loading

• Declares the recorder entry point that validates and starts a command-line replay request.

Generals/Code/GameEngine/Include/Common/Recorder.h

Recorder.cppResolve and preflight queued replays +49/-2

Resolve and preflight queued replays

• Reads absolute replay paths in place while retaining Replay-directory lookup for relative names. Validates replay headers, game options, and map availability before playback, quitting cleanly on failure.

Generals/Code/GameEngine/Source/Common/Recorder.cpp

GameState.cppSupport absolute save paths in Generals +20/-6

Support absolute save paths in Generals

• Centralizes save read-path resolution so command-line absolute paths open in place and relative menu names remain under the Save directory. Applies the helper to metadata, existence, and full-load paths.

Generals/Code/GameEngine/Source/Common/System/SaveGame/GameState.cpp

GameClient.cppStart queued replays after client initialization +5/-0

Start queued replays after client initialization

• Invokes replay loading from the established queued-load lifecycle point after shell setup, while retaining save-load priority.

Generals/Code/GameEngine/Source/GameClient/GameClient.cpp

GameState.hDeclare Zero Hour save path resolution +1/-0

Declare Zero Hour save path resolution

• Adds the Zero Hour API for resolving absolute save paths or managed-directory filenames.

GeneralsMD/Code/GameEngine/Include/Common/GameState.h

GlobalData.hStore Zero Hour replay startup requests +1/-0

Store Zero Hour replay startup requests

• Adds global startup state for the replay requested through '-loadreplay'.

GeneralsMD/Code/GameEngine/Include/Common/GlobalData.h

Recorder.hExpose Zero Hour queued replay loading +1/-0

Expose Zero Hour queued replay loading

• Declares the recorder entry point that validates and starts a command-line replay request.

GeneralsMD/Code/GameEngine/Include/Common/Recorder.h

Recorder.cppResolve and preflight Zero Hour replays +49/-2

Resolve and preflight Zero Hour replays

• Mirrors absolute and relative replay path handling for Zero Hour. Validates replay headers, game options, and map availability before playback, quitting cleanly on failure.

GeneralsMD/Code/GameEngine/Source/Common/Recorder.cpp

GameState.cppSupport absolute save paths in Zero Hour +20/-6

Support absolute save paths in Zero Hour

• Mirrors centralized save read-path resolution so absolute command-line paths open in place and relative names remain under the Save directory.

GeneralsMD/Code/GameEngine/Source/Common/System/SaveGame/GameState.cpp

GameClient.cppStart Zero Hour replays after initialization +5/-0

Start Zero Hour replays after initialization

• Invokes queued replay loading after shell setup in Zero Hour while retaining queued save-load priority.

GeneralsMD/Code/GameEngine/Source/GameClient/GameClient.cpp

[greptile-apps]

Greptile Summary

The PR adds normal-lifecycle replay playback through -loadreplay, including absolute-path resolution and early replay/map validation.

• Stores the requested replay in shared startup state and launches it after the shell initializes.
• Centralizes relative and absolute replay path resolution for menu, simulation, and playback callers.
• Applies the replay behavior consistently to Generals and Zero Hour.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
Core/GameEngine/Source/Common/CommandLine.cpp	Adds -loadreplay parsing and relaxes the existing simulation option's extension restriction.
Generals/Code/GameEngine/Source/Common/Recorder.cpp	Adds replay path resolution, queued-playback validation, and the normal client-lifecycle launch flow for Generals.
GeneralsMD/Code/GameEngine/Source/Common/Recorder.cpp	Mirrors replay path resolution and queued-playback behavior for Zero Hour.
Generals/Code/GameEngine/Source/GameClient/GameClient.cpp	Starts a queued replay after shell initialization, using the same startup point as queued save loading.
GeneralsMD/Code/GameEngine/Source/GameClient/GameClient.cpp	Mirrors the post-shell queued replay handoff in the Zero Hour client.
Generals/Code/GameEngine/Source/GameClient/GUI/GUICallbacks/Menus/ReplayMenu.cpp	Updates menu header reads to use the centralized filename and playback-mode contract.
GeneralsMD/Code/GameEngine/Source/GameClient/GUI/GUICallbacks/Menus/ReplayMenu.cpp	Applies the centralized replay-header API to the Zero Hour replay menu.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    CLI[-loadreplay path] --> Global[Store queued replay]
    Global --> Init[Initialize client and shell]
    Init --> Validate[Read replay header and validate map]
    Validate -->|Invalid replay| ReplayError[Show replay-load error and remain in menus]
    Validate -->|Missing map| MapError[Show map error and remain in menus]
    Validate -->|Valid| Playback[Open replay for playback]
    Playback --> Queue[Queue MSG_NEW_GAME]
    Queue --> Game[Start replay]
    Game --> Menus[Return to menus after playback]

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_{Reviews (7): Last reviewed commit: "feat(cli): Play a replay file from the c..." | Re-trigger Greptile}

[qodo-free-for-open-source-projects]

Code Review by Qodo

🐞 Bugs (1) 📘 Rule violations (0) 📎 Requirement gaps (1) 🎨 UX issues (0) 🔗 Cross-repo conflicts (0) 📜 Skill insights (0)

1. -ignoreReplaySyncErrors is unregistered 📎 Requirement gap ≡ Correctness

Description

The PR registers -loadreplay but does not register the required -ignoreReplaySyncErrors option,
so invoking the mandated suppression flag cannot set TheDebugIgnoreSyncErrors. Only the
differently named legacy -ignoresync option reaches parseSync.

Code

Core/GameEngine/Source/Common/CommandLine.cpp[1208]

+	{ "-loadreplay", parseLoadReplay },

Evidence

PR Compliance ID 6 explicitly requires suppression when -ignoreReplaySyncErrors is supplied. The
PR extends the startup command table with -loadreplay at line 1208, while the branch contains no
registration for -ignoreReplaySyncErrors; parseSync at lines 810-814 provides the required
behavior but is registered only under -ignoresync at line 1322.

Honor explicit replay synchronization error suppression
Core/GameEngine/Source/Common/CommandLine.cpp[810-814]
Core/GameEngine/Source/Common/CommandLine.cpp[1205-1208]
Core/GameEngine/Source/Common/CommandLine.cpp[1322-1322]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

## Issue description
`-loadreplay` must support the explicit `-ignoreReplaySyncErrors` command-line option, but that name is not registered.
## Issue Context
The existing `parseSync` handler already enables `TheDebugIgnoreSyncErrors`, and the legacy `-ignoresync` registration should remain compatible. Register the required option name as an alias to the same handler.
## Fix Focus Areas
- Core/GameEngine/Source/Common/CommandLine.cpp[1205-1208]
- Core/GameEngine/Source/Common/CommandLine.cpp[1319-1323]

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

---

2. Playerless replay crashes startup 🐞 Bug ≡ Correctness

Description

loadQueuedReplay() passes headers with localPlayerIndex == -1 into playbackFile(), which
dereferences getSlot(-1) and crashes instead of playing or cleanly rejecting the replay. The
recorder itself can write -1 for non-network single-player recordings, so -loadreplay can hit
this with a generated replay file.

Code

Generals/Code/GameEngine/Source/Common/Recorder.cpp[1117]

+	if (!playbackFile(filename))

Evidence

The replay writer initializes the recorded local index to -1 and leaves it unchanged for
non-network, non-skirmish single-player recording. The reader considers -1 valid, while the newly
invoked playback path passes it to GameInfo::getSlot, which returns null for negative indexes
before the caller dereferences it; GeneralsMD mirrors the same path.

Generals/Code/GameEngine/Source/Common/Recorder.cpp[590-640]
Generals/Code/GameEngine/Source/Common/Recorder.cpp[923-938]
Generals/Code/GameEngine/Source/Common/Recorder.cpp[1117-1120]
Generals/Code/GameEngine/Source/Common/Recorder.cpp[1191-1200]
Core/GameEngine/Source/GameNetwork/GameInfo.cpp[445-452]
GeneralsMD/Code/GameEngine/Source/Common/Recorder.cpp[1120-1123]
GeneralsMD/Code/GameEngine/Source/Common/Recorder.cpp[1194-1203]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

## Issue description
Queued playback can receive a valid replay header with `localPlayerIndex == -1`, but `playbackFile()` unconditionally dereferences that slot and crashes. Handle the no-local-player case without calling `getSlot(-1)`, and apply the equivalent fix to both game variants.
## Issue Context
`readReplayHeader()` explicitly accepts `-1`, and `startRecording()` can serialize `-1` for non-network single-player recordings. The multiplayer flag should only inspect a slot when the index is nonnegative; otherwise use the appropriate non-multiplayer default.
## Fix Focus Areas
- Generals/Code/GameEngine/Source/Common/Recorder.cpp[1117-1120]
- Generals/Code/GameEngine/Source/Common/Recorder.cpp[1191-1200]
- GeneralsMD/Code/GameEngine/Source/Common/Recorder.cpp[1120-1123]
- GeneralsMD/Code/GameEngine/Source/Common/Recorder.cpp[1194-1203]

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

---

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[tintinhamans]

There is no way to play a replay visually from the command line. -replay simulates headlessly, so an externally supplied .rep cannot be launched from an operating-system file handler and watched.

This is not entirely the case. -replay works fine without -headless.

[bobtista]

There is no way to play a replay visually from the command line. -replay simulates headlessly, so an externally supplied .rep cannot be launched from an operating-system file handler and watched.

This is not entirely the case. -replay works fine without -headless.

Yeah that's true, replay without -headless already plays visually. Fixed the description.
The difference is lifecycle:
-replay enters the replay-simulation workflow before the shell is shown and terminates the process after the replay workflow finishes.
-loadreplay queues a single replay after normal shell initialization, so playback returns to the menus afterward.
The absolute-path handling is shared, so this PR also allows -replay to open absolute paths. The separate option is specifically for the normal client lifecycle.

[bobtista]

Both are split into follow ups: -ignoreReplaySyncErrors is implemented in #3152, and the playerless replay crash is fixed in #3240.

[xezon]

Looks reasonable.