Bug#922485: brainparty: Minigame "Symbolic Logic": Premises are empty or contain garbage.

[Johann Suhter]

Package: brainparty
Version: 0.61+dfsg-3+b1
Severity: normal
Tags: patch

Dear Maintainer,

the minigame "Symbolic Logic" whithin brainparty cannot be played
because the premises are not shown.


Steps to reproduce:
    
Start the program and select the game "Symbolic Logic".
I can select it by clicking on 
- "PLAY!" 
- "PRACTISE" 
- 3 times "MORE" for searching the "Symbolic Logic" minigame
- the item in the middle which has an icon with a text like "All sales
  assist / wrestle crocodi / Catherine ...". 
- Then a description of the game appears, and I click anywhere on
  this description. 
- Now the game starts.


Expected behaviour:

I expect 3 sentences: Two premises and a conclusion.


Observed behaviour:

The conclusion is shown.
The two premises are completely missing, only two full stops appear.
Sometimes, I see some garbage characters instead.


Patch:

I have debugged the program a bit and I think the responsible function
is "const char* FlattenPremise(...)" which returns a pointer to a
temporary string object which is undefined behaviour.

I would suggest the following patch. The patch refers to
brainparty_0.61+dfsg-3 (I am on Debian stable), but when I browse the
sources on https://salsa.debian.org/games-team/brainparty the bug
still seems to exist.


--- a/symboliclogic.cpp Sat Feb 16 21:39:30 2019 +0100
+++ b/symboliclogic.cpp Sat Feb 16 21:49:13 2019 +0100
@@ -116,7 +116,7 @@
   }
 }
    
-const char* BPMiniGame_SymbolicLogic::FlattenPremise(BPMiniGame_SymbolicLogic_Premise* premise) {
+string BPMiniGame_SymbolicLogic::FlattenPremise(BPMiniGame_SymbolicLogic_Premise* premise) {
   ostringstream result;
   
   switch (premise->Type) {
@@ -150,7 +150,7 @@
         break;
   }
      
-  return result.str().c_str();
+  return result.str();
 }

 void BPMiniGame_SymbolicLogic::Tick() {

--- a/symboliclogic.h   Sat Feb 16 21:39:30 2019 +0100
+++ b/symboliclogic.h   Sat Feb 16 21:49:13 2019 +0100
@@ -67,7 +67,7 @@
   void Start();
   int GetWeight();
   void Render();
-  const char* FlattenPremise(BPMiniGame_SymbolicLogic_Premise* premise);
+  string FlattenPremise(BPMiniGame_SymbolicLogic_Premise* premise);
   void Tick();

   void OnMouseDown();



Thank you.


-- System Information:
Debian Release: 9.8
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.9.0-8-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_GB.utf8, LC_CTYPE=en_GB.utf8 (charmap=UTF-8), LANGUAGE=en_GB:en (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages brainparty depends on:
ii  brainparty-data           0.61+dfsg-3
ii  fonts-freefont-ttf        20120503-6
ii  libc6                     2.24-11+deb9u4
ii  libgcc1                   1:6.3.0-18+deb9u1
ii  libgl1-mesa-glx [libgl1]  13.0.6-1+b2
ii  libglu1-mesa [libglu1]    9.0.0-2.1
ii  libsdl-gfx1.2-5           2.0.25-5
ii  libsdl-image1.2           1.2.12-5+deb9u1
ii  libsdl-mixer1.2           1.2.12-11+b3
ii  libsdl-ttf2.0-0           2.0.11-3+b1
ii  libsdl1.2debian           1.2.15+dfsg1-4
ii  libstdc++6                6.3.0-18+deb9u1

brainparty recommends no packages.

brainparty suggests no packages.

-- no debconf information