What is spaghetti code? [closed]

Answer 1

From a Linux SCSI driver (which shall remain nameless to protect the guilty):

wait_nomsg:
        if ((inb(tmport) & 0x04) != 0) {
                goto wait_nomsg;
        }
        outb(1, 0x80);
        udelay(100);
        for (n = 0; n < 0x30000; n++) {
                if ((inb(tmport) & 0x80) != 0) {        /* bsy ? */
                        goto wait_io;
                }
        }
        goto TCM_SYNC;
wait_io:
        for (n = 0; n < 0x30000; n++) {
                if ((inb(tmport) & 0x81) == 0x0081) {
                        goto wait_io1;
                }
        }
        goto TCM_SYNC;
wait_io1:
        inb(0x80);
        val |= 0x8003;          /* io,cd,db7  */
        outw(val, tmport);
        inb(0x80);
        val &= 0x00bf;          /* no sel     */
        outw(val, tmport);
        outb(2, 0x80);
TCM_SYNC:
/* ... */
small_id:
        m = 1;
        m <<= k;
        if ((m & assignid_map) == 0) {
                goto G2Q_QUIN;
        }
        if (k > 0) {
                k--;
                goto small_id;
        }
G2Q5:                   /* srch from max acceptable ID#  */
        k = i;                  /* max acceptable ID#            */
G2Q_LP:
        m = 1;
        m <<= k;
        if ((m & assignid_map) == 0) {
                goto G2Q_QUIN;
        }
        if (k > 0) {
                k--;
                goto G2Q_LP;
        }
G2Q_QUIN:               /* k=binID#,       */

How did I locate this gem?

find /usr/src/linux -type f -name \*.c | 
while read f
do 
    echo -n "$f "
    sed -n 's/^.*goto *\([^;]*\);.*/\1/p' $f | sort -u | wc -l
done | 
sort +1rn |
head

The output is a series of lines listing files ordered by the number of gotos to distinct labels, like the following:

kernel/fork.c 31
fs/namei.c 35
drivers/infiniband/hw/mthca/mthca_main.c 36
fs/cifs/cifssmb.c 45
fs/ntfs/super.c 47

Answer 2

In simple terms spaghetti code is any code in any programming language in which it is not possible to trace the next post of execution, or at least difficult to determine where the next point goes in response of one action.

Answer 3

Spaghetti code: Originating in the early 60's in Italy as an alternate recipe for certain pasta dishes, spaghetti code was cooked up by one restaurant entrepreneur who attempted to automate the creation of a fool-proof entree. Pressed by the lack of time to complete the design the engineer/chef cut corners which introduced problems in the recipe early on. In a frantic attempt to remedy a good idea gone bad, various spices were quickly added to the concoction as the recipe grew out of control. The result was a stringy, twisty, yet potentially tasty pile of text that would later grow to be a practice cherished by developers world-wide.

Answer 4

There's also Ravioli Code, which is the opposite. Nice little chunks of functionality, a clean interface neatly wrapped around meaty goodness, all sat in a nice sauce of framework.

Answer 5

Real spaghetti-code requires a multitude of non-local gotos. Sadly this is not possible using most modern languages.

Edit: Some suggest exceptions and longjmp as substitutes for GOTO. But these are far to limited and structured, since they only allow you to return up the callstack. Real GOTO allows you to jump to any line anywhere in the program, which is necessary to create real spaghetti.

Answer 6

Don't forget to mention Object-oriented spaghetti. This is when you try to use all the design patterns in the book, even when they don't make sense. This leads to spaghetti code at conceptual level, which is far more detrimental to quality than classical goto-based spaghetti code.