Patch applicator

Executable

discopop_patch_applicator

Purpose

Apply, roll back, clear and restore parallelization suggestions in the form of the patch files created by the patch generator. The applicator keeps track of the applied suggestions, so you can undo them one by one or all at once.

Required input

Run the tool from inside the .discopop directory.

FileMapping.txt and the patch_generator/ folder (created by the explorer)
One action (see the options) and, for -a and -r, the suggestion ids

Output

The patches modify the source files named in FileMapping.txt in place. A suggestion is applied completely or not at all: if one of its files cannot be patched, the files already patched are restored.

The applicator keeps its state in patch_applicator/ (inside .discopop):

File	Contents
`applied_suggestions.json`	The ids of the applied suggestions.
`applied_suggestions.json.save`	The list saved by `-C`, restored by `-L`.
`application_result.json`	The outcome of the last `-a` call (`requested`, `applied`, `failed`, `unknown`, `already_applied`). Removed by `-C`.

The exit code is 0 if everything requested was applied, 1 if nothing could be applied and 2 if only some suggestions were applied. A rollback without suggestion ids ends with 3 (nothing to roll back).

Example

Run the explorer on example/example.cpp first. Then:

cd .discopop
discopop_patch_applicator -a 0 1   # apply suggestions 0 and 1
discopop_patch_applicator -l       # list the applied suggestions
discopop_patch_applicator -r 1     # roll back suggestion 1
discopop_patch_applicator -C       # reset the code to its original state (saves the list)
discopop_patch_applicator -L       # apply the saved suggestions again
discopop_patch_applicator -C       # reset again

-C overwrites an earlier save. Calling it twice in a row saves an empty list, so a following -L restores nothing.

Options

Option	Default	Description
`-a`, `--apply <id ...>`	none	Apply the suggestions with the given ids. Suggestions that are already applied are skipped.
`-r`, `--rollback <id ...>`	none	Roll back the suggestions with the given ids.
`-C`, `--clear`	off	Reset the code to its original state by rolling back all applied suggestions. The list of applied suggestions is saved for `-L`; an older save is overwritten.
`-L`, `--load`	off	Apply the suggestions saved by the last `-C`.
`-l`, `--list`	off	Print the applied suggestions. Nothing else is done.
`-v`, `--verbose`	off	Enable verbose output.
`--log`	`WARNING`	Log level: `DEBUG`, `INFO`, `WARNING`, `ERROR`, `CRITICAL`.
`--write-log`	off	Write a log file.

Only one action is executed per call, in the order -a, -r, -C, -L, -l.

Rolling back or clearing only works while the patched files still match the patches. If you edited a patched file by hand, the rollback fails.

Use from other tools

The MCP server offers the same actions as the tool manage_patches.
The autotuner and the project manager apply suggestions in a copy of the project.