Incorrect calculation of indentation width in case of mixed tabs and spaces in plistlib

[serhiy-storchaka]

Bug report

There is the indent parameter in plistlib._PlistWriter, which is b'\t' by default. write_bytes() calculates the width of the indentation, but doe it incorrect if the indentation is a mix of tabs and spaces.

Now, there is no public API to specify indent. it is always b'\t', for which an incorrect code works correctly. But if someone uses private plistlib._PlistWriter, they can encounter that bug.

Linked PRs

• gh-143346: Fix calculation of the line width for wrapped Base64 in plistlib #143347
• [3.14] gh-143346: Fix calculation of the line width for wrapped Base64 in plistlib (GH-143347) #143719
• [3.13] gh-143346: Fix calculation of the line width for wrapped Base64 in plistlib (GH-143347) #143720

[serhiy-storchaka]

#143347 fixes the calculation.

Other way -- just remove the indent parameter and hardcode its value.