Xmake Dev

Developing Xmake Itself

This skill is for working on the xmake-io/xmake source tree — not for projects that use xmake. Xmake is split into two layers:

• Lua layer (xmake/) — most of xmake's behavior: actions, modules, rules, toolchains, sandbox. Editable without recompiling.
• Native C core (core/src/xmake/) — the Lua runtime and xmake extension C APIs (os.*, io.*, process.*, fwatcher, etc.), plus tbox. Changes here require rebuilding the xmake binary.

1. Get the source

git clone --recursive https://github.com/xmake-io/xmake.git
cd xmake

Use --recursive — xmake bundles tbox and other submodules under core/src.

2. Build the xmake binary

Linux / macOS

./configure
make -j

Artifacts land in core/build/xmake (also symlinked via build/xmake).

Windows

cd core
xmake

This uses an existing xmake to bootstrap the new one; the resulting binary is core/build/xmake.exe.

Clean rebuild

make clean
./configure && make -j

On Windows: cd core && xmake clean && xmake.

3. Load the local source tree

So the xmake command in your shell points at the freshly built binary and loads Lua scripts from your checkout instead of the installed ~/.xmake:

Linux / macOS

source scripts/srcenv.profile
xmake --version

This script:

• aliases xmake to ./core/build/xmake (or ./build/xmake)
• sets XMAKE_PROGRAM_FILE to that binary
• sets XMAKE_PROGRAM_DIR to ./xmake (the Lua script tree)
• aliases xrepo to scripts/xrepo.sh
• prints the resolved programdir / programfile so you can verify

Windows

scripts\srcenv.bat

Opens a new shell pre-configured with XMAKE_PROGRAM_DIR and XMAKE_PROGRAM_FILE, and core\build on PATH.

Manual alternative

If you do not want to source the script, set the env vars yourself:

export XMAKE_PROGRAM_DIR=/path/to/xmake/xmake      # the Lua tree
export XMAKE_PROGRAM_FILE=/path/to/xmake/core/build/xmake

Now every xmake invocation in any project uses your local checkout.

Verify with:

xmake l xmake.programdir
xmake l xmake.programfile

Both should point inside your checkout.

4. Debugging the Lua layer

This is the fast loop — no rebuild required. Once srcenv.profile is sourced, edit any file under xmake/ and rerun xmake in a test project to see the effect.

Print-style debugging

-- inside xmake/modules/... or xmake/actions/...
import("core.base.option")
print("DEBUG value = %s", some_table)
utils.vprint("only in -v mode: %s", val)     -- verbose-gated
cprint("${bright}colored output${clear}")

Run the user's command with diagnostics:

xmake -vD build            # -v verbose, -D diagnosis (full Lua tracebacks)

-D turns every error into a stack trace anchored in the Lua source files — point at those line numbers to find the failure.

Inspecting state

import("core.base.option")
import("core.project.project")
import("core.project.config")

print(config.plat(), config.arch(), config.mode())
for name, target in pairs(project.targets()) do
    print("target %s -> %s", name, target:targetfile())
end

Run ad-hoc Lua with the full xmake module environment:

xmake l -vD path/to/script.lua
xmake l -c 'print(os.host(), os.arch())'

Interactive REPL

xmake l
> import("core.base.option")
> print(os.host())

Great for exploring module APIs (core.project.project, lib.detect.find_tool, core.tool.toolchain, …).

Running the xmake test suite

xmake l tests/run.lua                 # full suite
xmake l tests/run.lua [testname]      # one group

Tests live under tests/ in the xmake checkout; each directory is a mini project exercising a feature.

5. Debugging the native C core

Native code is under core/src/xmake/ (Lua C bindings), core/src/sv/, and the bundled core/src/tbox. Changes require a rebuild; the Lua tree is untouched.

Build a debug binary

cd /path/to/xmake
./configure --mode=debug
make -j

(Or, equivalently, building core/ directly: cd core && xmake f -m debug && xmake.)

The resulting core/build/xmake has symbols and assertions enabled. srcenv.profile still points at it, so xmake in any project now runs the debug binary.

Run under a debugger

Linux:

gdb --args ./core/build/xmake build -vD
(gdb) break xm_os_cpdir            # any C symbol in core/src/xmake
(gdb) run

macOS:

lldb -- ./core/build/xmake build -vD
(lldb) b xm_os_cpdir
(lldb) run

Windows (MSVC): open core/build/xmake.exe in Visual Studio, set it as startup target, pass the command-line args, and set breakpoints in core/src/xmake/*.c.

Where the C bindings live

• core/src/xmake/os/ — os.cp, os.mv, os.ls, process spawn, …
• core/src/xmake/io/ — io.open, io.readable, …
• core/src/xmake/process/ — subprocess handling
• core/src/xmake/fwatcher/ — file watching
• core/src/xmake/string/, hash/, base64/, libc/ — misc helpers

Each C function is registered to Lua under a name like xm_os_cpdir. The full call path for a user-visible API is:

sandbox_os.cp()   (xmake/core/sandbox/modules/os.lua)
  -> os.cp()      (xmake/core/base/os.lua)
    -> os.cpdir() bound to xm_os_cpdir()  (core/src/xmake/os/cpdir.c)
      -> tb_directory_copy()              (core/src/tbox)

To trace a misbehaving os.cp, set a breakpoint in xm_os_cpdir (C) and drop a print(...) in xmake/core/base/os.lua (Lua) — you usually need both sides to understand what arguments crossed the boundary.

Adding a new C binding

1. Add the C function in core/src/xmake/<module>/<name>.c.
2. Register it in that module's xmake.h / registration table.
3. Expose it from the matching xmake/core/base/<module>.lua wrapper.
4. Optionally add a sandbox wrapper under xmake/core/sandbox/modules/<module>.lua.
5. make -j to rebuild.
6. xmake l -c 'print(os.mynewfn())' to smoke test.

Memory / leak checks

./configure --mode=debug
make -j
valgrind --leak-check=full ./core/build/xmake build -vD
# or on macOS
leaks --atExit -- ./core/build/xmake build -vD

tbox ships its own allocator hooks as well — look under core/src/tbox/src/tbox/memory.

6. Common commands while developing

xmake -vD                         # verbose + Lua tracebacks on error
xmake l path/to/script.lua        # run arbitrary Lua in xmake env
xmake l xmake.programdir          # which script tree is active
xmake l xmake.programfile         # which binary is active
xmake g --clean                   # clear global caches if something is stuck
xmake f -c                        # re-run configure on a test project

7. Pitfalls

• Forgot to source srcenv.profile. xmake will still resolve to the installed binary in /usr/local/bin, so your Lua edits in the checkout appear to do nothing. Confirm with xmake l xmake.programdir.
• Edited a Lua file that lives under ~/.xmake/repositories/.... That is a clone of xmake-repo, not the xmake source — changes there affect package recipes, not xmake itself.
• Native changes not taking effect. Rebuild (make -j). If you only ran source srcenv.profile, that does not recompile — it just points at whatever binary you already have.
• Stale configure cache. After switching between --mode=debug and --mode=release, run ./configure --mode=<mode> again before make.
• Submodules out of date after a pull. git submodule update --init --recursive.

When to branch out

• Writing a user-facing plugin or custom task → xmake-plugins
• Authoring a rule or handling a new file extension → xmake-rules
• Working on a package recipe in xmake-repo → xmake-repo-testing