Was this different before 2015? What changed in 2015?
For applications made after June 2015, due to changes in the law under Harper's Strengthening Canadian Citizenship Act, the PR must meet an
actual physical presence requirement to qualify for a grant of citizenship. While the newly elected (later that year) Liberal government promptly proceeded to table and adopt legislation walking back many of the more draconian elements of the SCCA, like the required intent to continue residing in Canada requirement, it only modified the actual physical presence requirement, rolling it back to a 3/5 rule rather than the Harper 4/6 rule. But it is still an actual physical presence rule. A PR must be actually physically present in Canada for at least 3 years in a five year period to be eligible for a grant of citizenship. (Again, there are narrow exceptions which are not much relevant here.)
For applications made prior to June 2015 Citizenship Judges had discretion to approve the grant of citizenship for PRs based on "
residency" in Canada rather than actual physical presence, and indeed many were granted citizenship even though they spent less than three or even less than two years actually in Canada. That said, by 2008 or 2009 the Harper government had implemented stricter screening for "
residency" based applications and even before the SCCA's physical presence requirement took effect in June 2015 that had made it increasingly more difficult for those who did not meet the actual presence standard (at that time it was a 3/4 rule).
Citizenship Judges have no such discretion at all now. The Minister has no authority to exercise such discretion either.
There is no work-around the physical presence requirement . . .
. . . except in situations like a PR member of the Canadian armed forces getting credit for days deployed abroad, and a few very narrow other exceptions.
If you still have not established yourself in Canada long enough to obtain citizenship when you win a Nobel prize in Chemistry or Medicine, or made the scientific breakthrough that saves the world from climate change, you might qualify for a special grant of citizenship. Getting citizenship down that route, grossly understating the odds, is at the very best a long-shot, a very, very long-shot.