Por que o feitiço Fidelius na casa dos oleiros foi invadido?

TL, DR In canon the Fidelius Charm is inconsistently presented. It smacks of deus ex machina and seems to be clumsily applied mainly to smooth out or facilitate plot points that need some assistance getting from point A to point B. There is not a satisfactory answer as to why the charm broke in the way that it did because Fidelius does not have defined parameters. ETA: Regarding your comment to Pureferret, it doesn't make sense that the charm broke while Harry was still alive. It's a ótimo question. It's just that there is no authoritative canon-based answer and the supplemental information provided by J.K. Rowling doesn't explain it either. There is absolutely no canon evidence that Wormtail "undid" the charm prior to Voldemort killing the Potters. Hence my concerns with the workings of the Fidelius Charm in general.

The long version:

Response to both your question and mina on the Fidelius Charm show how confusing canon is surrounding this issue. Since I asked about Fidelius, I've done a lot of digging and reading and have concluded Fidelius is probably somewhat of a deus ex machina. When canon isn't clear and J.K. Rowling provides what is supposed to be clarifying information to be considered alongside what she's written in canon, it's truly difficult to suss it out. :) Here are some examples of what's been said about the Fidelius Charm:

‘An immensely complex spell,’ [Flitwick] said squeakily, ‘involving the magical concealment of a secret inside a single, living soul. The information is hidden inside the chosen person, or Secret-Keeper, and is henceforth impossible to find – unless, of course, the Secret- Keeper chooses to divulge it. As long as the Secret-Keeper refused to speak, You-Know-Who could search the village where Lily and James were staying for years and never find them, not even if he had his nose pressed against their sitting-room window!’

_{Prisoner of Azkaban - pages 152-153 - Bloomsbury - chapter 10, The Marauder's Map}

This is the first canon description of the Fidelius Charm, so this is what we have to go by off the bat.

‘Here,’ Moody muttered, thrusting a piece of parchment towards Harry’s Disillusioned hand and holding his lit wand close to it, so as to illuminate the writing. ‘Read quickly and memorise.’

Harry looked down at the piece of paper. The narrow handwriting was vaguely familiar. It said:

The Headquarters of the Order of the Phoenix may be found at number twelve, Grimmauld Place, London.

_{Order of the Phoenix - page 57 - Bloomsbury - chapter 3, The Advance Guard}

Here we are shown how a Secret-Keeper can share the secret with others, by telling them directly. So far we can assume that a secret can be divulged verbally (Peter Pettigrew, we assume) and through writing. As well, appropriately, Harry cannot see No. Twelve Grimmauld Place until well after he's read Dumbledore's message. (I do have an overall point)

They were often joined by other Order members for dinner now, because The Burrow had replaced number twelve, Grimmauld Place as the Headquarters.

Mr Weasley had explained that after the death of Dumbledore, their Secret Keeper, each of the people to whom Dumbledore had confided Grimmauld Place’s location had become a Secret Keeper in turn.

‘And as there are around twenty of us, that greatly dilutes the power of the Fidelius Charm. Twenty times as many opportunities for the Death Eaters to get the secret out of somebody. We can’t expect it to hold much longer.’

_{Deathly Hallows - page 79 - Bloomsbury - chapter 6, The Ghoul in Pyjamas}

Now we learn that the Fidelius Charm may be complex, but it's not as stable as some spells. It dilutes as a new person is told the secret and becomes weaker. Okay. It's also noted that the headquarters for the Order of the Phoenix have relocated from Grimmauld to the Burrow. There's no indication of whether or not the Burrow was placed under the Fidelius Charm as well. (Personally, I think headquartering the Order's headquarters at the Burrow would be far more obvious to the Death Eaters than Grimmauld Place, and even more dangerous. Although, I suppose, to be fair, Kreacher did rat out the Order to Narcissa Malfoy in Ordem da Fenix)

Regarding Yaxley in Deathly Hallows:

‘Harry, I think he can. I – I forced him to let go with a Revulsion Jinx, but I’d already taken him inside the Fidelius Charm’s protection. Since Dumbledore died, we’re Secret Keepers, so I’ve given him the secret, haven’t I?’

_{Deathly Hallows - page 223 - Bloomsbury - chapter 14, The Thief}

Esperar. O QUE? Now an outsider can learn a Fidelius secret by osmose, just by having accidental contact with whatever is being protected by Fidelius? According to Flitwick's description of Fidelius in Prisioneiro de Azkaban, a secret must be specifically divulged to another person, and the two examples we saw of divulging a secret previously were through writing or verbally. So Yaxley just sabia, even though nothing was explained to him? As well, Mr. Weasley had informed Harry that the Order's headquarters had been moved to a new location. There is no explanation as to why the trio couldn't have immediately stunned Yaxley and tossed him right out of No. Twelve Grimmauld Place because the Fidelius Charm originally protecting Grimmauld especificamente involved the address for the headquarters of the Order of the Phoenix. It wasn't Oh, and by the way, Harry Potter is hiding out here at number twelve Grimmauld Place. By the time Yaxley hit the hearth, Grimmauld não era headquarters anymore. So exactly what secret was divulged? And how?

‘I’ve been getting them all out of The Burrow,’ he explained. ‘Moved them to Muriel’s. The Death Eaters know Ron’s with you now, they’re bound to target the family – don’t apologise,’ he added, at the sight of Harry’s expression. ‘It was always a matter of time, Dad’s been saying so for months. We’re the biggest blood traitor family there is.’

‘How are they protected?’ asked Harry.

‘Fidelius Charm. Dad’s Secret Keeper. And we’ve done it on this cottage too; I’m Secret Keeper here.

_{Deathly Hallows - page 390 - Bloomsbury - chapter 24, The Wandmaker}

So Shell Cottage was under the Fidelius Charm at the moment Dobby Apparated the trio out from Malfoy Manor. How is it possible that Harry could see it, see it's lights, and see people moving about inside antes Bill Weasley told Harry about the charm and that he (Bill) was the Secret Keeper for Shell Cottage? (Bill also rather blithely tells Harry that a group of Weasleys -- which might include Ginny -- was under the protection of Fidelius at Auntie Muriel's. For the Weasleys' continued protection, it would have been wiser for Bill not to tell Harry this information. There wasn't a pressing need for Harry to know where the Weasleys were at that moment in time.).

Here is what J.K. Rowling has to say about Fidelius:

What happens to a secret when the Secret-Keeper dies?

I was surprised that this question won, because it is not the one that I’d have voted for… but hey, if this is what you want to know, this is what you want to know!

When a Secret-Keeper dies, their secret dies with them, or, to put it another way, the status of their secret will remain as it was at the moment of their death. Everybody in whom they confided will continue to know the hidden information, but nobody else.

Just in case you have forgotten exactly how the Fidelius Charm works, it is “an immensely complex spell involving the magical concealment of a secret inside a single, living soul. The information is hidden inside the chosen person, or Secret-Keeper, and is henceforth impossible to find — unless, of course, the Secret-Keeper chooses to divulge it” (Harry Potter and the Prisoner of Azkaban)

In other words, a secret (eg, the location of a family in hiding, like the Potters) is enchanted so that it is protected by a single Keeper (in our example, Peter Pettigrew, a.k.a. Wormtail). Thenceforth nobody else – not even the subjects of the secret themselves – can divulge the secret. Even if one of the Potters had been captured, force fed Veritaserum or placed under the Imperius Curse, they would not have been able to give away the whereabouts of the other two. The only people who ever knew their precise location were those whom Wormtail had told directly, but none of them would have been able to pass on the information.¹

J.K. Rowling

So how could Yaxley have known even a smidgen of information regarding Grimmauld Place?

See how muddy the water is?

This is a really, really long post to demonstrate why I think the answer to your question is that it's unclear why the charm broke. The information surrounding Fidelius is inconsistent and appears to be infinite, meaning there aren't fixed parameters around the magic involved. Fidelius just seems to keep morphing and changing as canon goes along.

¹_{This was on J.K. Rowling's website for years, but she's taken down all her Potter information in order to put it up on Pottermore. Link courtesy of the Wayback Machine}

It appears that the Fidelius Charm can be broken by the Secret Keeper. From Deathly Hallows ch 17 "Bathilda's Secret," when Harry is reliving Voldemort's memory of going to kill the Potters: "...and now his destination was in sight at last, the Fidelius Charm broken, though they did not know it yet..." This indicates that the Charm itself had already been broken prior to the Potter's deaths and the backfire of the curse on Harry, implying the Secret Keeper (Pettigrew) had broken it.

I was under the impression, purely from my reading of the books, that all the charm did was made a secret, and anything related unknowable undiscoverable, so long as the secret keeper kept the secret. In fact, quoting the harry potter wikia

The Fidelius Charm is a complex and powerful Charm that takes a specific piece of information (a secret) and implants it into a being's soul.

As such, if the secret was the residence of the Potters or the location of the Potters the fact that they have died means they no longer have a location or residence. There is no longer a secret.

Furthermore, the secret keeper, the real subject of the charm, let the secret loose. If breaking the charm required death, all that would be required was to kill everyone close to the Potters. It's much harder to subtly extract the secret, and thus more secure.

Again quoting HP Wikia:

Whilst one cannot force secondary Keepers to divulge the information they have learnt, it is unknown if coercive methods to have the primary Keeper reveal the location (such as Veritaserum or the Imperius Curse) would work.

It appears that once the primary secret keeper dies the others that know of the information become secondary secret keepers (i.e, when the Albus dies and the secret of Grimmauld place is no longer 'kept', Snape is now a secondary secret keeper.)

Again this is mostly from memory, and HP-Wikia so I don't know for certain.

I think we should consider the secret that the Fidelius charm was protecting. From the Prisoner of Azkaban, Chapter 10 - The Marauder's Map: (McGonnagall speaking to Flitwik, Fudge and Rosmerta):

"James Potter told Dumbledore that Black would die rather than tell where they were, that Black was planning to go into hiding himself... "

The wording strongly suggests that the secret was the location of the Potters.

Also, we have this from Harry Potter and the Sorcerer's Stone, Chapter 1 The Boy who Lived:(Hagrid speaking to Dumbledore)

"No, sir - house was almost destroyed, but I got him out right before the Muggles started swarmin around".

From that - we know that the location that was being protected by the Fidelius charm was almost destroyed - which might have made it possible right then for the Muggles to see the house.

Now - when Harry realises that the FIdelius charm must have broken - he observes the house from outside. (Harry Potter and the Deathly Hollows - Chapter 17: Bathilda's Secret)

The hedge had grown wild in the sixteen years since Hagrid had taken Harry from the rubble that lay scattered amongst the waist-high grass. Most of the cottage was still standing, though entirely covered in the dark ivy and snow, but the right side of the top floor had been blown apart; that, Harry was sure, was where the curse had backfired. He and Hermione stood at the gate, gazing up at the wreck of what must once have been a cottage just like those that flanked it. "I wonder why nobody's ever rebuilt it?" whispered Hermione. "Maybe you can't rebuild it?" Harry replied. "Maybe it's like the injuries from Dark Magic and you can't repair the damage?"

Although Harry assumes that the damage cannot be repaired and compares it to injuries from Dark Magic - if it were indeed true - we can confirm that the damage to the house itself was beyond repair.

So the charm wasn't broken by the death of James and Lily - nor by Wormtail revealing the secret to all the people who left their wishes (we know he could not have - since he was thought to have been killed by Sirius immediately after James and Lily's death). The charm broke because the house that it was protecting was destroyed - presumably when Voldemort's killing curse rebounded instead of killing Harry.

The spell was no longer in effect when Voldemort got to the house

Sabemos da HP and the Cursed Child that the spell no longer in effect antes Voldemort arrived at Godric's Hollow, presumably because Pettigrew had canceled the spell entirely rather than because he let Voldemort in on the secret.

Scorpius Malfoy and Albus Potter use a time-turner to travel back to the 1980s, immediately prior to Voldemort's arrival. Both of these individuals can see the house, indicating that it's no longer protected by the Fidelius Charm.

e

SCORPIUS: And here it is —

ALBUS: The home of James, Lily, and Harry Potter . . .

A young, attractive couple leave a house with a baby in a pushchair. ALBUS moves towards them, SCORPIUS pulls him back.

SCORPIUS: They can’t see you, Albus, it might damage time, and we’re not doing that — not this time.

RE: the Cursed Child

It does seem pretty clear from the Cursed Child that whatever Pettigrew did to reveal the secret to Voldemort must have destroyed the enchantment completely, since the house is visible to Albus and Scorpius, and eventually to Harry, Ron, Hermione, Ginny and Draco.

RE: the introduction of it in Prisoner of Azkaban

To me the confusing part has always been that to switch out secret keepers meant that no one, except Sirius and Peter, knew the secret, not even Dumbledore. If Dumbledore had known, then he could have testified on Sirius' behalf. Yet Dumbledore knew what had happened in Godric's Hollow quickly enough to notify Hagrid to get Harry prior to the Muggle police showing up.

It is traditional in many fantasy universes for certain types of spells/charms to elapse/break when the caster dies. It seems that the most likely explanation is that the Fidelius Charm is such a spell and that, since the most likely caster of the charm was either James Potter or Lily Potter, that it almost certainly died with them.

pettigrew/wormtail may have been alive but the reason the fidilus charm broke is because pettigrew told voldemort where to find them once the secret keeper tells someone who wants to find the person for the wrong reasons the charm breaks