I have a change where I massively decalred the bitblt operands as unsigned int.

I did not push it so far, but I'll try to see if it solves the symptoms.

2016-03-31 3:16 GMT+02:00 Levente Uzonyi <leves@caesar.elte.hu>:

Hi Eliot,

I made a snippet to read the source of the method as an array of integers from the .mcz in the package cache:

(MCMczReader versionFromFile: 'package-cache/Multilingual-ul.210.mcz') snapshot definitions
        detect: [ :each |
                each isMethodDefinition
                        and: [ each className = #JapaneseEnvironment
                                and: [ each selector = #flapTabTextFor:in: ] ] ]
        ifFound: [ :definition |
                Array streamContents: [ :stream |
                        | source |
                        source := definition source.
                        1 to: source size do: [ :index |
                                stream nextPut: (source basicAt: index) ] ] ]
        ifNone: [ self error ]

In MCMczReader >> #loadDefinitions, if you change this line

                [:m | [^definitions := (DataStream on: m contentStream) next definitions]

to this

                [:m | [ self error. ^definitions := (DataStream on: m contentStream) next definitions]

then the definition will be read from the sources instead of the binary snapshot, and you'll get the correct source code.

First I disabled all the ZipPlugin primitives to see if those are responsible for this issue, but they turned out to be okay.
Then I dag into DataStream, and I came to the conclusion that the issue is in BitBlt. The mangled characters appear when PositionableStream >> #nextWordsInto: applies some BitBlt magic to convert the read bytes into a WideString.

Here's a snippet triggering the error:

| wideString source pos blt expectedWideString |
source := #[1 64 255 14 1 64 48 251].
expectedWideString := WideString fromByteArray: source.
wideString := WideString new: source size // 4.
pos := 0.
blt := (BitBlt
        toForm: (Form new hackBits: wideString))
        sourceForm: (Form new hackBits: source).
blt
        combinationRule: Form over;
        sourceX: 0;
        sourceY: pos // 4;
        height: wideString byteSize // 4;
        width: 4;
        destX: 0;
        destY: 0;
        copyBits.
wideString restoreEndianness.
self assert: wideString = expectedWideString

Levente