Always cache the default tools tree

For the default tools tree, the cached image and the final image
are the same for all intents and purposes, so let's stop storing both
a cached image and a final image for the default tools tree and instead
only store the final image and use it as the cached image by always
writing a cache manifest next to it.

At the same time always use the name mkosi.tools to reduce the chance
of conflicts as "tools" is an incredibly common directory name.

diff --git a/mkosi/__init__.py b/mkosi/__init__.py
index 0539473e32cf511e23cfa150223a93214eec58a7..602ee2e2f01a5d165f71574a0578f87f4899f9de 100644 (file)
--- a/mkosi/__init__.py
+++ b/mkosi/__init__.py
@@ -2593,6 +2593,13 @@ def print_output_size(path: Path) -> None:
 
 
 def cache_tree_paths(config: Config) -> tuple[Path, Path, Path]:
+    if config.image == "tools":
+        return (
+            config.output_dir_or_cwd() / "mkosi.tools",
+            config.output_dir_or_cwd() / "mkosi.tools.build.cache",
+            config.output_dir_or_cwd() / "mkosi.tools.manifest",
+        )
+
     assert config.cache_dir
     return (
         config.cache_dir / f"{config.expand_key_specifiers(config.cache_key)}.cache",
@@ -3200,7 +3207,8 @@ def save_cache(context: Context) -> None:
 
 
 def have_cache(config: Config) -> bool:
-    if not config.is_incremental():
+    # The default tools tree is always cached regardless of the incremental mode.
+    if not config.is_incremental() and config.image != "tools":
         return False
 
     final, build, manifest = cache_tree_paths(config)
@@ -4506,16 +4514,13 @@ def finalize_default_tools(config: Config, *, resources: Path) -> Config:
         f"--cache-only={config.cacheonly}",
         *([f"--output-directory={os.fspath(p)}"] if (p := config.output_dir) else []),
         *([f"--workspace-directory={os.fspath(p)}"] if (p := config.workspace_dir) else []),
-        *([f"--cache-directory={os.fspath(p)}"] if (p := config.cache_dir) else []),
-        "--cache-key=tools",
         *([f"--package-cache-directory={os.fspath(p)}"] if (p := config.package_cache_dir) else []),
-        f"--incremental={config.incremental}",
+        "--incremental=no",
         *([f"--package={package}" for package in config.tools_tree_packages]),
         *([f"--package-directory={os.fspath(directory)}" for directory in config.tools_tree_package_directories]),  # noqa: E501
         *([f"--build-sources={tree}" for tree in config.build_sources]),
         f"--build-sources-ephemeral={config.build_sources_ephemeral}",
         *([f"--prepare-script={os.fspath(script)}" for script in config.tools_tree_prepare_scripts]),
-        "--output=tools",
         *([f"--source-date-epoch={e}"] if (e := config.source_date_epoch) is not None else []),
         *([f"--environment={k}='{v}'" for k, v in config.environment.items()]),
         *([f"--proxy-url={config.proxy_url}"] if config.proxy_url else []),
@@ -5038,10 +5043,8 @@ def run_verb(args: Args, images: Sequence[Config], *, resources: Path) -> None:
 
     # If we're doing an incremental build and the cache is not out of date, don't clean up the
     # tools tree so that we can reuse the previous one.
-    if tools and (
-        not tools.is_incremental() or ((args.verb == Verb.build or args.force > 0) and not have_cache(tools))
-    ):
-        if tools.incremental == Incremental.strict:
+    if tools and ((args.verb == Verb.build or args.force > 0) and not have_cache(tools)):
+        if last.incremental == Incremental.strict:
             die(
                 "Tools tree does not exist or is out-of-date but the strict incremental mode is enabled",
                 hint="Build once with '-i yes' to update the tools tree",
@@ -5078,6 +5081,10 @@ def run_verb(args: Args, images: Sequence[Config], *, resources: Path) -> None:
                 keyring_dir=Path(keyring_dir),
                 metadata_dir=Path(metadata_dir),
             )
+            _, _, manifest = cache_tree_paths(tools)
+            manifest.write_text(
+                json.dumps(tools.cache_manifest(), cls=JsonEncoder, indent=4, sort_keys=True)
+            )
 
     if not args.verb.needs_build():
         return {