createPairs() raises IndexError when the keyword count is odd

[dmccoystephenson]

createPairs() indexes self.keywords[i+1] with no bounds check:

def createPairs(self):
    # match keywords in pairs
    for i in range(0, len(self.keywords), 2):
        pair = []
        pair.append(self.keywords[i])
        pair.append(self.keywords[i+1])
        self.pairs.append(pair)

When the keyword list has an odd length, the final iteration reads past the end and raises IndexError.

Verification

The method was called directly on a 3-element list:

$ python3 -c "
import sys
sys.path.insert(0, 'src')
from ideaCollisionGenerator import IdeaCollisionGenerator
g = IdeaCollisionGenerator()
g.keywords = ['a', 'b', 'c']
try:
    g.createPairs()
    print('no error, pairs =', g.pairs)
except IndexError as e:
    print('IndexError:', e)
"
IndexError: list index out of range

Reachability

This is not reachable through the CLI today, because getKeywords() hardcodes numKeywords = 10. It becomes reachable the moment the keyword count is made configurable, or whenever createPairs() is called on a list assembled some other way.

Suggested resolution

A fix should decide explicitly what an odd trailing keyword means — most plausibly that it is dropped, or that it forms a one-element pair — rather than adding a silent guard. Whichever is chosen, the fix should arrive with a test that calls createPairs() directly on an odd-length list, since the behavior cannot be observed through the CLI.

This issue body was drafted during a Gardener session (https://github.com/Stephenson-Software/gardener).

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drafted by Claude on behalf of Daniel Stephenson