Why file get overwritten when KeyPath is set in Wix - wix

Question

The snippet of Files.wxs generated by heat:
<?xml version="1.0" encoding="utf-8"?>
<Wix
xmlns="http://schemas.microsoft.com/wix/2006/wi">
<Fragment>
<DirectoryRef Id="INSTALLFOLDER">
<Directory Id="dirF5D9BDF13CBC346EDDFD6D0959FFB838" Name="config">
<Component Id="cmp0CBEDCE6B62E5666B3362D0EB41267BC" Guid="*">
<File Id="fil73D1987B7864F07C97735D7E40243AB2" KeyPath="yes"
Source="$(var.App.TargetDir)\config\accounts-example.ini" />
</Component>
</Component>
</Directory>
</DirectoryRef>
</Fragment>
<Fragment>
<ComponentGroup Id="Binaries">
<ComponentRef Id="cmp0CBEDCE6B62E5666B3362D0EB41267BC" />
</ComponentGroup>
</Fragment>
</Wix>
Product.wxs:
<?xml version="1.0" encoding="utf-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi"
xmlns:netfx="http://schemas.microsoft.com/wix/NetFxExtension">
<Product Id="*" Name="xxx" Language="2052" Version="$(var.ProductVersion)" Manufacturer="xxx"
UpgradeCode="425BDA6F-31B8-47AD-88D8-4B2DBE394XXX">
<Package InstallerVersion="200" Compressed="yes" InstallScope="perMachine" />
<MajorUpgrade AllowSameVersionUpgrades="yes" DowngradeErrorMessage="New Version [ProductName] has been installed。" />
<MediaTemplate EmbedCab="yes" />
<WixVariable Id="WixUILicenseRtf" Value="./License.rtf" />
<Directory Id="TARGETDIR" Name="SourceDir">
<Directory Id="ProgramFilesFolder">
<Directory Id="MANUFACTURERFOLDER" Name="!(bind.property.Manufacturer)">
<Directory Id="INSTALLFOLDER" Name="!(bind.property.ProductName)" />
</Directory>
</Directory>
<Directory Id="ProgramMenuFolder">
<Directory Id="ApplicationProgramsFolder" Name="!(bind.property.ProductName)" />
<Directory Id="DesktopFolder" Name="Desktop" />
</Directory>
</Directory>
<Feature Id="ProductFeature" Title="XXX_Installer" Level="1">
<ComponentGroupRef Id="Binaries" />
<ComponentRef Id="ApplicationShortcut" />
<ComponentRef Id="ApplicationShortcutDesktop" />
<ComponentRef Id="RegistryEntries" />
</Feature>
<UIRef Id="WixUI_ErrorProgressText" />
<Property Id="WIXUI_INSTALLDIR" Value="INSTALLFOLDER" />
<UIRef Id="WixUI_InstallDir" />
<DirectoryRef Id="ApplicationProgramsFolder">
<Component Id="ApplicationShortcut" Guid="E1F61345-CC60-40FE-8FC4-FBE1598F8XXX">
<Shortcut Id="ApplicationStartMenuShortcut"
Name="!(bind.property.ProductName)"
Description="!(bind.property.ProductName)"
Target="[INSTALLFOLDER]XXX_App.exe"
WorkingDirectory="INSTALLFOLDER" />
<RemoveFolder Id="ApplicationProgramsFolder" On="uninstall" />
<RegistryValue Root="HKCU" Key="Software\Microsoft\!(bind.property.ProductName)" Name="installed" Type="integer" Value="1" KeyPath="yes" />
</Component>
</DirectoryRef>
<DirectoryRef Id="DesktopFolder">
<Component Id="ApplicationShortcutDesktop" Guid="BEDF111F-0889-4317-8E67-41425F00CXXX">
<Shortcut Id="ApplicationDesktopShortcut"
Name="!(bind.property.ProductName)"
Description="!(bind.property.ProductName)"
Target="[INSTALLFOLDER]XXX_App.exe"
WorkingDirectory="INSTALLFOLDER" />
<RemoveFolder Id="DesktopFolder" On="uninstall" />
<RegistryValue Root="HKCU" Key="Software\Microsoft\!(bind.property.ProductName)" Name="installed" Type="integer" Value="1" KeyPath="yes" />
</Component>
</DirectoryRef>
<DirectoryRef Id="TARGETDIR">
<Component Id="RegistryEntries" Guid="0D919675-E219-43EA-AAB3-E6F81A013XXX">
<RegistryKey Root="HKCU"
Key="Software\Microsoft\Windows\CurrentVersion\Run">
<RegistryValue Name="!(bind.property.ProductName)"
Type="string"
Value="[INSTALLFOLDER]XXX_App.exe"/>
</RegistryKey>
</Component>
</DirectoryRef>
<UI>
<Publish Dialog="ExitDialog"
Control="Finish"
Event="DoAction"
Value="LaunchApplication">WIXUI_EXITDIALOGOPTIONALCHECKBOX = 1 and NOT Installed</Publish>
</UI>
<Property Id="WIXUI_EXITDIALOGOPTIONALCHECKBOXTEXT" Value="启动!(bind.property.ProductName)" />
<Property Id="WIXUI_EXITDIALOGOPTIONALCHECKBOX" Value="1" />
<Property Id="WixShellExecTarget" Value="[INSTALLFOLDER]XXX_App.exe" />
<CustomAction Id="LaunchApplication"
BinaryKey="WixCA"
DllEntry="WixShellExec"
Impersonate="yes" />
</Product>
</Wix>
Every time I install a new version, it overwrites the existing file accounts-example.ini.
The overwrite behavior is expected for accounts-example.ini, but I will have another file user.db do not want to be overwritten.
It says if KeyPath is set to 'yes' then it doesn't overwrite the existing file, isn't it? How could I config Wix to overwrite one file and not overwirte another?
Some articles about KeyPath:
what-is-the-wix-keypath-attribute
copy-if-not-exist-in-wix

Answer 1

If you are doing this with a majorupgrade element you need to tell us where it's scheduled. If it's "early" (such as afterInstallInitialize) then everything will be uninstalled first, and then the new upgrade installed, and every file that was installed will be from the new upgrade. If it's sequenced "late" (such as afterInstallExecute) then the overwrite rules apply (such as this https://msdn.microsoft.com/en-us/library/windows/desktop) and that's because the upgrade basically installs each file over the existing files.
Note that the WiX default for the MajorUpgrade schedule is afterInstallValidate, so as I described (and as the WiX documentation says) the entire older product will be uninstalled first (obviously removing all files) then all the new files will be installed.
See schedule here:
http://wixtoolset.org/documentation/manual/v3/xsd/wix/majorupgrade.html
The explanation at the WiX keypath link leaves a lot to be desired. It is not really true to say that if the component is present none of its resources will be installed. It's not clear to me what that is intended to mean because the overwrite rules will be applied.
As far as your data files are concerned, they will not be overwritten by an incoming file if they have been updated since they were installed. So it's likely that your ini file is being overwritten because it hasn't been changed. If your db has been updated then it won't be replaced, but, again, this is overwrite rules when your major upgrade is "late" (or it's a patch).