From 7498dbfc22121233c4f9166d198ff0f227be04cc Mon Sep 17 00:00:00 2001
From: Daan De Meyer <daan.j.demeyer@gmail.com>
Date: Tue, 25 Mar 2025 14:41:26 +0100
Subject: [PATCH] Make sure tools tree recorded in history doesn't change when
 in sandbox

Currently, when in the sandbox, the tools tree will always be recorded
as "null" in the history. This causes problems if an image build is done
inside of mkosi sandbox and mkosi is later invoked outside of the sandbox
as the history will say no tools tree was used and so the tools tree won't
be used, even if we're running outside of the sandbox.

To fix the issue, let's make sure we always record the proper tools tree,
but let's not make use of it in the sandbox by moving the sandbox check to
the Config object's tools() method.

We also simplify all the tools tree related checks in run_verb() and add a
check to make sure we don't try to rebuild the default tools tree when in
"mkosi sandbox" as that can't ever work.
---
 mkosi/__init__.py | 59 ++++++++++++++++++-----------------------------
 mkosi/config.py   |  7 ++++++
 2 files changed, 29 insertions(+), 37 deletions(-)

diff --git a/mkosi/__init__.py b/mkosi/__init__.py
index f81e45450..e36e71691 100644
--- a/mkosi/__init__.py
+++ b/mkosi/__init__.py
@@ -72,6 +72,7 @@ from mkosi.config import (
     expand_delayed_specifiers,
     format_bytes,
     have_history,
+    in_sandbox,
     parse_boolean,
     parse_config,
     resolve_deps,
@@ -4041,10 +4042,6 @@ def build_image(context: Context) -> None:
     print_output_size(context.config.output_dir_or_cwd() / context.config.output_with_compression)
 
 
-def in_sandbox() -> bool:
-    return parse_boolean(os.getenv("MKOSI_IN_SANDBOX", "0"))
-
-
 def run_sandbox(args: Args, config: Config) -> None:
     if in_sandbox():
         die(
@@ -4993,21 +4990,14 @@ def run_verb(args: Args, images: Sequence[Config], *, resources: Path) -> None:
 
     last = images[-1]
 
-    if not in_sandbox() and last.tools_tree and last.tools_tree == Path("default"):
+    if last.tools_tree and last.tools_tree == Path("default"):
         tools = finalize_default_tools(last, resources=resources)
+
+        for i, config in enumerate(images):
+            images[i] = dataclasses.replace(config, tools_tree=tools.output_dir_or_cwd() / tools.output)
     else:
         tools = None
 
-    for i, config in enumerate(images):
-        if in_sandbox():
-            tools_tree = None
-        elif tools and config.tools_tree == Path("default"):
-            tools_tree = tools.output_dir_or_cwd() / tools.output
-        else:
-            tools_tree = config.tools_tree
-
-        images[i] = dataclasses.replace(config, tools_tree=tools_tree)
-
     # The images array has been modified so we need to reevaluate last again.
     last = images[-1]
 
@@ -5025,33 +5015,28 @@ def run_verb(args: Args, images: Sequence[Config], *, resources: Path) -> None:
 
         return
 
-    if (
-        tools
-        and (
-            not (tools.output_dir_or_cwd() / tools.output).exists()
-            or (tools.is_incremental() and not have_cache(tools))
-        )
-        and args.verb != Verb.build
-        and not args.force
-    ):
-        die(
-            f"Default tools tree requested for image '{last.image}' but it is out-of-date or has not been "
-            "built yet",
-            hint="Make sure to (re)build the image first with 'mkosi build' or use '--force'",
-        )
-
-    # 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 ((args.verb == Verb.build or args.force > 0) and not have_cache(tools)):
-        if last.incremental == Incremental.strict:
+    # For the default tools tree have_cache() encompasses the "has the tools tree been built at all" check.
+    if tools and not have_cache(tools):
+        if args.verb != Verb.build and args.force == 0:
+            die(
+                f"Default tools tree requested for image '{last.image}' but it is out-of-date or has not "
+                "been built yet",
+                hint="Make sure to (re)build the tools tree first with 'mkosi build' or use '--force'",
+            )
+        elif in_sandbox():
+            die(
+                "Cannot rebuild out-of-date default tools tree from inside mkosi sandbox",
+                hint="Exit mkosi sandbox and re-enter the sandbox again with mkosi -f sandbox to "
+                "rebuild the default tools tree",
+            )
+        elif 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",
+                "Default tools tree is out-of-date but the strict incremental mode is enabled",
+                hint="Build once without --incremental=strict to rebuild the default tools tree",
             )
 
         run_clean(args, tools)
 
-    if tools and not (tools.output_dir_or_cwd() / tools.output).exists():
         check_tools(tools, Verb.build)
         ensure_directories_exist(tools)
 
diff --git a/mkosi/config.py b/mkosi/config.py
index 59ae35cbf..e8f352161 100644
--- a/mkosi/config.py
+++ b/mkosi/config.py
@@ -650,6 +650,10 @@ def parse_boolean(s: str) -> bool:
     return value
 
 
+def in_sandbox() -> bool:
+    return parse_boolean(os.getenv("MKOSI_IN_SANDBOX", "0"))
+
+
 def parse_path(
     value: str,
     *,
@@ -2116,6 +2120,9 @@ class Config:
         return self.package_cache_dir or (INVOKING_USER.cache_dir() / "mkosi" / key)
 
     def tools(self) -> Path:
+        if in_sandbox():
+            return Path("/")
+
         return self.tools_tree or Path("/")
 
     @classmethod
-- 
2.47.2