update changelog and add some comments for #3628

CHANGELOG.md

@@ -11,6 +11,7 @@
 * [#3596](https://github.com/xmake-io/xmake/issues/3596): Fix check_cxxfuncs and check_cxxsnippets
 * [#3603](https://github.com/xmake-io/xmake/issues/3603): Fix `xmake update`
 * [#3614](https://github.com/xmake-io/xmake/issues/3614): Fix qt envirnoment when running target
+* [#3628](https://github.com/xmake-io/xmake/issues/3628): Fix msys2/mingw setenv and os.exec issue
 * Fix setenv for msys/mingw
 
 ## v2.7.8
@@ -1576,6 +1577,7 @@
 * [#3596](https://github.com/xmake-io/xmake/issues/3596): 修复 check_cxxfuncs 和 check_cxxsnippets
 * [#3603](https://github.com/xmake-io/xmake/issues/3603): 修复 xmake update 的无效 url
 * [#3614](https://github.com/xmake-io/xmake/issues/3614): 修复 xmake run 对 Qt 环境的加载
+* [#3628](https://github.com/xmake-io/xmake/issues/3628): 修复 msys2/mingw 下 os.exec 总是优先查找错误的可执行程序
 * 修复 msys/mingw 下环境变量设置问题
 
 ## v2.7.8

core/src/demo/xmake.sh

@@ -28,6 +28,16 @@ target "demo"
     add_installfiles "${projectdir}/(xmake/templates/**)" "share"
     add_installfiles "${projectdir}/scripts/xrepo.sh" "bin" "xrepo"
 
+    # fix os.exec() call incorrect program from /mingw64/bin. e.g. python, ..
+    #
+    # because xmake is installed to /mingw64/bin/xmake,
+    # os.exec/CreateProcess always gives the highest priority to finding the process from /mingw64/bin (if it exists),
+    # rather than from the $PATH environment variable.
+    #
+    # we install the xmake executable into a separate directory to ensure
+    # that os.exec() does not look for additional executables.
+    #
+    # @see https://github.com/xmake-io/xmake/issues/3628
     if is_host "msys"; then
         add_installfiles "${projectdir}/scripts/msys/xmake.sh" "bin" "xmake"
         add_installfiles "${buildir}/xmake.exe" "share/xmake"