Heads up: an array of structs initialisation in style.cpp

Hi,

I just git pulled the most recent code to my Mac and compiled the app. The result: MuseScore crashes on startup. After poking around the code, I found the culprit: the styleTypes-array initialisation in style.cpp

style.cpp:50
static const StyleType styleTypes[] {
      { StyleIdx::staffUpperBorder,        "staffUpperBorder",        Spatium(7.0)  },
      ...

The precomputeValues-function loops through the styleTypes-array, and while debugging, I noticed that only _idx-property is set. StyleType's _name is null, and it seems that the _defaultValue QVariant is empty as well.

AFAIK lasconic noticed that crash on startup on Mac (and on Mac only, for
some strange reason) but haven't jet found the time to investigate, due to
the musescore.com changes that needed his full attentuin in the past couple
days.

Most likely culprit is
https://github.com/musescore/MuseScore/commit/0b1aea952f9f870ef79f39899f8ec1
2cc2b60fa6, as per 'git blame'.

Bye, Jojo

-----Original Message-----
From: rumpu-jussi [mailto:[hidden email]]
Sent: Saturday, January 14, 2017 11:25 AM
To: [hidden email]
Subject: [Mscore-developer] Heads up: an array of structs initialisation in
style.cpp

Hi,

I just git pulled the most recent code to my Mac and compiled the app. The
result: MuseScore crashes on startup. After poking around the code, I found
the culprit: the styleTypes-array initialisation in style.cpp

style.cpp:50
static const StyleType styleTypes[] {
      { StyleIdx::staffUpperBorder,        "staffUpperBorder",      
Spatium(7.0)  },
      ...

The precomputeValues-function loops through the styleTypes-array, and while
debugging, I noticed that only _idx-property is set. StyleType's _name is
null, and it seems that the _defaultValue QVariant is empty as well.





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Sorry, I got too carried away. None of the values in the styleTypes-array are set. The array contains X amount of empty structs...

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It seems that with this issue we are deep in the territory of clang vs gcc implementations of global variable initialisation especially regarding an array of structs. That goes way beyond my understanding.

However, I made a quick'n'dirty workaround:

1. styleTypes is now declared as such:

static StyleType styleTypes[int(StyleIdx::STYLES)];

2. MStyle constructor has a local variable, initializer, declared as such:

          static const StyleType initializer[] {
              { StyleIdx::staffUpperBorder,        "staffUpperBorder",        Spatium(7.0)  },
              ...

3. The first thing the constructor does is to copy the values from initializer into styleTypes:

          for (int i=0;i<int(StyleIdx::STYLES);i++) {
              styleTypes[i]=initializer[i];
          }

Note that the local variable's (initializer) declaration/initialization is identical to the original styleTypes declaration. The problem here is related on how those global arrays are initialised in clang.

I may post a question to StackOverflow if there are gurus who can instruct on how to initialise a static const array of structs with clang.