Bug report
Bug description:
#127592 added support for redirecting stdout/stderr to the Apple System Log when running on macOS and iOS, using the os_log() method.
However macOS 26 has slightly altered the operation the system log. All "dynamic" strings (that is, any string that is constructed at runtime, rather than being a statically defined in source code), appears in the system log as <private>. All Python logging messages will be dynamic by definition, so this change renders Python system logging useless on macOS 26.
While the private/public message split existed on previous versions of macOS, the default behavior of the system logger allowed dynamic messages to be viewed.
The fix is to format the string using os_log(..., "%{public}s", ....), rather than a simple "%s" definition.
An immediate workaround is to apply a custom logging profile. Save the following as a file named private-logging.mobileconfig
Contents of `private-logging.mobileconfig`
<?xml version="1.0"encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>PayloadContent</key>
<array>
<dict>
<key>PayloadDisplayName</key>
<string>ManagedClient logging</string>
<key>PayloadEnabled</key>
<true/>
<key>PayloadIdentifier</key>
<string>com.apple.logging.ManagedClient.1</string>
<key>PayloadType</key>
<string>com.apple.system.logging</string>
<key>PayloadUUID</key>
<string>ED5DE307-A5FC-434F-AD88-187677F02222</string>
<key>PayloadVersion</key>
<integer>1</integer>
<key>System</key>
<dict>
<key>Enable-Private-Data</key>
<true/>
</dict>
</dict>
</array>
<key>PayloadDescription</key>
<string>Enable Unified Log Private Data logging</string>
<key>PayloadDisplayName</key>
<string>Enable Unified Log Private Data</string>
<key>PayloadIdentifier</key>
<string>C510208B-AD6E-4121-A945-E397B61CACCF</string>
<key>PayloadRemovalDisallowed</key>
<false/>
<key>PayloadScope</key>
<string>System</string>
<key>PayloadType</key>
<string>Configuration</string>
<key>PayloadUUID</key>
<string>D30C25BD-E0C1-44C8-830A-964F27DAD4BA</string>
<key>PayloadVersion</key>
<integer>1</integer>
</dict>
</plist>
Double click on the file in finder, then navigate to the "Device Management" tab in system settings, and approve the "Enable Unified Log Private Data logging" profile.
Applying this profile requires admin permissions, and it applies to all logging, so it's not really appropriate as a general solution.
CPython versions tested on:
CPython main branch
Operating systems tested on:
macOS
Linked PRs
Bug report
Bug description:
#127592 added support for redirecting stdout/stderr to the Apple System Log when running on macOS and iOS, using the
os_log()method.However macOS 26 has slightly altered the operation the system log. All "dynamic" strings (that is, any string that is constructed at runtime, rather than being a statically defined in source code), appears in the system log as
<private>. All Python logging messages will be dynamic by definition, so this change renders Python system logging useless on macOS 26.While the private/public message split existed on previous versions of macOS, the default behavior of the system logger allowed dynamic messages to be viewed.
The fix is to format the string using
os_log(..., "%{public}s", ....), rather than a simple"%s"definition.An immediate workaround is to apply a custom logging profile. Save the following as a file named
private-logging.mobileconfigContents of `private-logging.mobileconfig`
Double click on the file in finder, then navigate to the "Device Management" tab in system settings, and approve the "Enable Unified Log Private Data logging" profile.
Applying this profile requires admin permissions, and it applies to all logging, so it's not really appropriate as a general solution.
CPython versions tested on:
CPython main branch
Operating systems tested on:
macOS
Linked PRs