If the srcdir is a symlink, Ikiwiki will not render the pages unless the srcdir has a trailing slash.

For example:

    #!/bin/sh
    set -x

    REALSRCDIR=~/tmp/ikiwiki/wikiwc2
    SRCDIR=~/tmp/ikiwiki/wikiwc
    DESTDIR=~/tmp/ikiwiki/public_html/wiki/

    echo "*** Testing without trailing slash."

    rm -rf $REALSRCDIR $SRCDIR $DESTDIR

    # Create the real srcdir and link the srcdir to it
    mkdir -p $REALSRCDIR
    ln -s $REALSRCDIR $SRCDIR

    mkdir -p $DESTDIR

    echo Test > $SRCDIR/index.mdwn

    # No trailing slash after $SRCDIR
    ikiwiki --verbose $SRCDIR $DESTDIR --url=http://example.org/~you/wiki/ --underlaydir /dev/null

    echo "*** Testing with trailing slash."

    rm -rf $REALSRCDIR $SRCDIR $DESTDIR

    # Create the real srcdir and link the srcdir to it
    mkdir -p $REALSRCDIR
    ln -s $REALSRCDIR $SRCDIR

    mkdir -p $DESTDIR

    echo Test > $SRCDIR/index.mdwn

    # Trailing slash after $SRCDIR
    ikiwiki --verbose $SRCDIR/ $DESTDIR --url=http://example.org/~you/wiki/ --underlaydir /dev/null

My output:

    + REALSRCDIR=/home/svend/tmp/ikiwiki/wikiwc2
    + SRCDIR=/home/svend/tmp/ikiwiki/wikiwc
    + DESTDIR=/home/svend/tmp/ikiwiki/public_html/wiki/
    + echo '*** Testing without trailing slash.'
    *** Testing without trailing slash.
    + rm -rf /home/svend/tmp/ikiwiki/wikiwc2 /home/svend/tmp/ikiwiki/wikiwc /home/svend/tmp/ikiwiki/public_html/wiki/
    + mkdir -p /home/svend/tmp/ikiwiki/wikiwc2
    + ln -s /home/svend/tmp/ikiwiki/wikiwc2 /home/svend/tmp/ikiwiki/wikiwc
    + mkdir -p /home/svend/tmp/ikiwiki/public_html/wiki/
    + echo Test
    + ikiwiki --verbose /home/svend/tmp/ikiwiki/wikiwc /home/svend/tmp/ikiwiki/public_html/wiki/ --url=http://example.org/~you/wiki/ --underlaydir /dev/null
    + echo '*** Testing with trailing slash.'
    *** Testing with trailing slash.
    + rm -rf /home/svend/tmp/ikiwiki/wikiwc2 /home/svend/tmp/ikiwiki/wikiwc /home/svend/tmp/ikiwiki/public_html/wiki/
    + mkdir -p /home/svend/tmp/ikiwiki/wikiwc2
    + ln -s /home/svend/tmp/ikiwiki/wikiwc2 /home/svend/tmp/ikiwiki/wikiwc
    + mkdir -p /home/svend/tmp/ikiwiki/public_html/wiki/
    + echo Test
    + ikiwiki --verbose /home/svend/tmp/ikiwiki/wikiwc/ /home/svend/tmp/ikiwiki/public_html/wiki/ --url=http://example.org/~you/wiki/ --underlaydir /dev/null
    scanning index.mdwn
    rendering index.mdwn

Note that index.mdwn was only rendered when srcdir had a trailing slash.