The wording of the "reach" clearly identifies that the reach only applies to OAs with it. So War caster won't benefit from the increased reach.
Warcaster replaces the opportunity attack with a spell, so does in fact benefit from the increased reach.
Provoke at 10ft? Sub out for a spell via warcaster.
Except that you don't provoke at 10'.
The rules on Reach reads: "Most creatures have a 5-foot reach and can thus attack targets within 5 feet of them when making a melee attack." The rules on the Reach property of weapons says: "This weapon adds 5 feet to your reach when you attack with it, as well as when determining your reach for opportunity attacks with it." If you do not attack with a weapon with the Reach property, your reach remains 5' and so you cannot make opportunity attacks at 10'. You don't provoke an opportunity attack at 10' by having a reach weapon in hand, rather, you are allowed to make an opportunity attack at 10' with a reach weapon. It is the act of attacking with the reach weapon that creates the additional 5' of reach, it does not exist until you do.
You cannot attack with it if the enemy doesn't provoke. Saying your reach is only 10ft for the attack, not for the provoking of the attack, means you actually cannot use opportunity attacks with reach weapons beyond 5ft.
You've logic knotted yourself into a contradiction.
I disagree. If you are wielding a reach weapon and a creature moves more than 10' from you, you state that you will use your reaction to make an opportunity attack on it with your reach weapon. You may do so, because that is what the rules on reach weapons and opportunity attacks say you can do.
The word "provoke" does not appear in either the rules for reach weapons nor in those for opportunity attacks, only in the rules for the Warcaster feat. And if you are going to cast a spell, then you are not attacking with a reach weapon, so your reach is not increased and it remains 5'.
The wording of the "reach" clearly identifies that the reach only applies to OAs with it. So War caster won't benefit from the increased reach.
Warcaster replaces the opportunity attack with a spell, so does in fact benefit from the increased reach.
Provoke at 10ft? Sub out for a spell via warcaster.
Except that you don't provoke at 10'.
The rules on Reach reads: "Most creatures have a 5-foot reach and can thus attack targets within 5 feet of them when making a melee attack." The rules on the Reach property of weapons says: "This weapon adds 5 feet to your reach when you attack with it, as well as when determining your reach for opportunity attacks with it." If you do not attack with a weapon with the Reach property, your reach remains 5' and so you cannot make opportunity attacks at 10'. You don't provoke an opportunity attack at 10' by having a reach weapon in hand, rather, you are allowed to make an opportunity attack at 10' with a reach weapon. It is the act of attacking with the reach weapon that creates the additional 5' of reach, it does not exist until you do.
You cannot attack with it if the enemy doesn't provoke. Saying your reach is only 10ft for the attack, not for the provoking of the attack, means you actually cannot use opportunity attacks with reach weapons beyond 5ft.
You've logic knotted yourself into a contradiction.
I disagree. If you are wielding a reach weapon and a creature moves more than 10' from you, you state that you will use your reaction to make an opportunity attack on it with your reach weapon. You may do so, because that is what the rules on reach weapons and opportunity attacks say you can do.
The word "provoke" does not appear in either the rules for reach weapons nor in those for opportunity attacks, only in the rules for the Warcaster feat. And if you are going to cast a spell, then you are not attacking with a reach weapon, so your reach is not increased and it remains 5'.
Are you confusing reach with spell range? We'r not saying the spells range gets increased to 10ft (if it were somehow less than that) for example. Only that you're casting the spell instead of making the opportunity attack. if you were going to make an opportunity attack because the enemy left 10', you instead cast a spell at them.
Edit: As for provoke, an enemy provokes an opportunity attack when: they give you the option to make an opportunity attack.
So "When a hostile creature's movement provokes an opportunity attack from you, you can use your reaction to cast a spell at the creature, rather than making an opportunity attack." means that whenever you are eligible to make an opportunity attack because the enemy moved out of your reach, you are also eligible to instead cast a spell as a reaction. Regardless what your reach is for that opportunity attack is.
It is apparently so hard to program Aberrant Mind and Clockwork Soul spell-swapping into dndbeyond they had to remake the game without it rather than implement it.
Nicandor, you are blatantly and obviously disagreeing with RAW and RAI. If you have a weapon in hand that you can attack at 10 ft, then moving through that area provokes an AoO. Warcaster lets you replace that AoO with a spell. There is no special wording that you seem to think exists.
If you continue to disagree, please stop hijacking this thread and make your own, with a POLL. I am absolutely sure you will find that the overwhelming population here disagrees with you.
That is OK. You can play as you like. But understand that everyone else will consider you to be house ruling.
P.S. if you do this and the Poll proves you right, I will abase myself in the thread, heaping you with praise.
Not sure where the "reach weapons can't provoke OAs beyond 10 feet" argument came from. That is kind of half the weapon property.
Either reach weapons provoke an OA at 10 feet that can be replaced by warcaster, OR reach weapons don't provoke an OA at 10 feet and therefore can't attack.
Warcaster replaces just the weapon attack that was already triggered by the attack's reach.
Not sure where the "reach weapons can't provoke OAs beyond 10 feet" argument came from. That is kind of half the weapon property.
Either reach weapons provoke an OA at 10 feet that can be replaced by warcaster, OR reach weapons don't provoke an OA at 10 feet and therefore can't attack.
Warcaster replaces just the weapon attack that was already triggered by the attack's reach.
Post #14 is the first reference to it in this thread. Apparently you can find a JC tweet that says that's the intent too, though the entry concerning Reach in SAC makes no mention of war caster and vice versa.
Edit: following that logic and the guidance in the SAC, though, then with war caster and a reach weapon, you can never cast a spell as an opportunity attack. The SAC says a creature moving 5'->10' doesn't provoke an opportunity attack with a reach weapon, and moving 10'->15' doesn't allow you to use war caster. (I know there is an idea out there that you have multiple reaches, but that is a bad idea and only matters when you are actually wielding 2 weapons.)
According to that, then not only does this combo not work as intended, it is fundamentally worse than having either parts (reach weapon or war caster) individually.
I will make one last attempt to explain my reasoning and then I am done.
A character has a reach of 5'.
A character holding a reach weapon has a reach of 5'.
A character with a reach weapon gains 5' of additional reach when they attack with it.
A character can make an OA with a reach weapon at 10', because the act of attacking with the reach weapon gives them the required additional reach, per the rules on reach weapons.
A character holding a reach weapon and a dagger has a reach of 5'.
A character holding a reach weapon and a dagger cannot make an OA at 10' with the dagger, because their reach is only 5'.
A character holding a reach weapon and a dagger can make an OA at 10' with the reach weapon, because the act of attacking with with the reach weapon gives them the required additional reach, per the rules on reach weapons.
A character with Warcaster holding a reach weapon has a reach of 5'.
An opponent is 10' away from the Warcaster and moves another 5' away. This does not "provoke" an OA because the opponent did not move out of the reach of the Warcaster, since they did not start within the reach of the Warcaster.
The Warcaster can, however, make an OA at 10' with the reach weapon, because the act of attacking with the reach weapon gives them the required additional reach, per the rules on reach weapons.
Holding a reach weapon does not give you 5' of additional reach. Attacking with it does.
I will make one last attempt to explain my reasoning and then I am done.
A character has a reach of 5'.
A character holding a reach weapon has a reach of 5'.
A character with a reach weapon gains 5' of additional reach when they attack with it.
A character can make an OA with a reach weapon at 10', because the act of attacking with the reach weapon gives them the required additional reach, per the rules on reach weapons.
[Snip]
A character with Warcaster holding a reach weapon has a reach of 5'.
An opponent is 10' away from the Warcaster and moves another 5' away. This does not "provoke" an OA because the opponent did not move out of the reach of the Warcaster, since they did not start within the reach of the Warcaster.
The Warcaster can, however, make an OA at 10' with the reach weapon, because the act of attacking with the reach weapon gives them the required additional reach, per the rules on reach weapons.
Holding a reach weapon does not give you 5' of additional reach. Attacking with it does.
And the problem with your reasoning is the rules for opportunity attacks:
You can make an opportunity attack when a hostile creature that you can see moves out of your reach. To make the opportunity attack, you use your reaction to make one melee attack against the provoking creature. The attack occurs right before the creature leaves your reach.
If a character with a reach weapon has a reach of 5, then the attack (presumably with a reach of 10) is not provoked and cannot be made.
OA with weapon: move out of weapon reach triggers weapon attack.
OA with warcaster: move out of weapon reach triggers weapon attack, weapon attack is replaced with spell.
Holding a reach weapon does not give you 5' of additional reach. Attacking with it does.
That is one of two things that the reach property does. It also gives you 5' of additional reach when determining your reach for opportunity attacks with it.
So the question is what opportunity attacks can you replace with a spell. Assuming the "with it" in the reach rule is a hard requirement is a bit of a cop out, because it could be just context for the actual weapon the reach property is describing. War Caster makes no caveats, indicating that any opportunity attack can be replaced with a spell. With that being said, these rules are in conflict and neither is more specific than the other (there aren't general tiers of "weapon properties are more specific than feats") so you have to make a ruling.
But that being said, the advice that even Jeremy Crawford has given about reaches is contradictory and the whole topic needs a bit of a cleanup.
Assume you are a caster (Warlock, Arcana Cleric, etc) whom uses a whip (only one handed reach weapon). You also take the Warcaster feat. Now you have 5ft reach and the Warcaster feat specifies that movement based AoO can be taken with a spell instead of the weapon.
To really screw with it, attack with a movement based spell attack, such as Lance of Lethargy, Grasp of Hadar, Lightning Lure, etc, pulling them closer to you or ending their movement.
Have I missed something or is this a nasty little tactic about as good as Sentinel (speed becomes as 0)?
I can't tell exactly what your question is, so to explicitly cover every base I can think of:
War Caster works on any provoked OA, and reach works for OA purposes, so in this example, you could cast the spell to replace an OA that would have been taken due to the whip's reach. You could do the same thing with a glaive.
Reach doesn't stop you from taking OAs (typically unarmed ones) without reach, so in this example, you could cast the spell to replace an OA that would have been taken due to your own, native reach (the one your unarmed strikes have).
The above logic extends across every weapon you are currently wielding, whatever they are, which may have independent reach values. For example, suppose your DM has homebrewed a super-reach whip for you (and you're a standard-issue PC, i.e. 5 foot base reach). While wielding the super-whip and a whip, OAs are provoked from you at 5, 10, and 15 feet. Any of them can be replaced with a spell using War Caster.
Suppose your base reach has gone up somehow, so you have 10 foot reach somehow on everything, including unarmed strikes. You won't be able to take 5 foot OAs any more, so War Caster won't be able to trigger.
I will bite one last time. Your reach is increased, either for making an attack, or determining your reach for opportunity attacks with it, when you attack with a reach weapon. If you do not attack with it, you do not get the additional 5' of reach. The wording of reach does not say "when determining your reach for opportunity attacks PERIOD", it says "when determining your reach for opportunity attacks with it." Getting the 5' of additional reach, for either purpose, only happens when you attack with it. Surely no one is suggesting that, if I have a whip in my right hand, I can punch someone 10' away with my left as an OA.
You cannot replace an OA made with a reach weapon at 10' with a spell attack with Warcaster, because if you did, the attack with the reach weapon would not take place, and so your reach would remain 5' and no OA would have been provoked. This is no different than not being able to make an OA at 10' with a non reach weapon, or an unarmed strike, even if you are holding a reach weapon in the other hand.
The requirement for an OA to take place that your opponent move out of your reach does not prevent you from making an OA with a reach weapon at 10' even when your unmodified reach is 5'. The rules on reach weapons explicitly say that, when you make an attack with a reach weapon, or for determining your reach for opportunity attacks with it, you gain 5' of additional reach, so if you make the OA with a reach weapon, your reach is 10' and the conditions for making an OA are met.
I will bite one last time. Your reach is increased, either for making an attack, or determining your reach for opportunity attacks with it, when you attack with a reach weapon.
No, this is false. Your reach is not increased only when you attack; it is increased when determining your reach for opportunity attacks with the weapon. Actually making the attack is not required. I just gave you the literal, exact definition of reach, which does what I am saying it does and not what you are saying it does. I will repeat the relevant piece here:
"as well as when determining your reach for opportunity attacks with it"
So, for example, suppose you had a magic lantern that lit up whenever you were within reach of a potential OA (maybe it was invented by a wizard who was afraid of polearm-wielding ghosts, I don't know). The lantern would work without any requirement that the OAs actually be made, due to the RAW wording of reach, which I have provided.
If you do not attack with it, you do not get the additional 5' of reach.
This is false, as discussed above. If you need to know your reach for the purposes of an opportunity attack, the reach property explicitly applies, whether or not the attack is made.
The wording of reach does not say "when determining your reach for opportunity attacks PERIOD", it says "when determining your reach for opportunity attacks with it." Getting the 5' of additional reach, for either purpose, only happens when you attack with it.
Again, false, see above. For example, if you're wielding a magic reach weapon whose enchantment is "anyone who provokes an OA from you while you're wielding this must make a Wisdom save or lose 5 feet of movement", it would happen even if you didn't take the OA. You are correct that reach applies only to the weapon with the property - wielding a glaive doesn't give you Reach on your Unarmed Strikes - but you are otherwise incorrect.
Surely no one is suggesting that, if I have a whip in my right hand, I can punch someone 10' away with my left as an OA.
You are exactly right.
You cannot replace an OA made with a reach weapon at 10' with a spell attack with Warcaster, because if you did, the attack with the reach weapon would not take place, and so your reach would remain 5' and no OA would have been provoked. This is no different than not being able to make an OA at 10' with a non reach weapon, or an unarmed strike, even if you are holding a reach weapon in the other hand.
No, because you're mischaracterizing how War Caster works. War Caster works when anyone provokes an OA from you, and if you have a reach weapon, someone moving from 10 feet away to 15 feet away from you provokes an OA. It then replaces the attack. It's exactly like how a Tasha's Beast Master can take the Attack action and replace an attack with a Companion order: the attack is replaced after meeting the necessary conditions to perform it.
The requirement for an OA to take place that your opponent move out of your reach does not prevent you from making an OA with a reach weapon at 10' even when your unmodified reach is 5'. The rules on reach weapons explicitly say that, when you make an attack with a reach weapon, or for determining your reach for opportunity attacks with it, you gain 5' of additional reach, so if you make the OA with a reach weapon, your reach is 10' and the conditions for making an OA are met.
Over and out.
As another example of your interpretation breaking feats, you're ruling that Polearm Master's second bullet doesn't work at all. As in, it literally does nothing according to you. You're aware of that, right? Because Polearm Master's second bullet reacts to something entering your weapon-augmented reach before you've made the attack in order to let you do something, just like War Caster's third bullet. Tell me honestly, have you ever played under a DM (i.e. not your own rules, literally anyone else's) who agreed with you that Polearm Master's second bullet does literally nothing at all?
Well, they agree with all the things required to trigger the opportunity attack, but not that the trigger applies if the triggered attack is replaced.
By that logic, since opportunity attacks are melee attacks and reach is how far you can target "when making a melee attack." So the 3rd bullet point of war caster must do nothing since all "reach" only applies to melee attacks, so if you are not making a melee attack, no opportunity attack was provoked.
I prefer the RAW of keeping the trigger and replacing the reaction, rather than all replacement effects having to be a valid option for what they are replacing (and therefore doing nothing because why would they be a replacement if they were already a valid option?).
Lets do some basic fill in the blank/substitutions based on what the rules say:
Basic Rule: You can make an opportunity attack when a hostile creature that you can see moves out of your reach.
Lets fill in the blank for defined reach.
Basic+Defined: You can make an opportunity attack when a hostile creature that you can see moves out of your reach5ft.
Now we apply Reach property: This weapon adds 5 feet to your reach when you attack with it, as well as when determining your reach for opportunity attacks with it.
Basic+Defined+Reach: You can make an opportunity attack when a hostile creature that you can see moves out of your reach5ft10ft.
Now finish it off with adding in warcaster.
Basic+Defined+Reach+Warcaster: You can make an opportunity attack, or you can use your reaction to cast a spell at the creature, when a hostile creature that you can see moves out of your reach5ft10ft.
Except you missed a step:
* Decide not to actually attack with the whip, so your reach reverts to 5 ft.
(Since your reach is only 10 ft while you are performing an OA with it.)
* Decide not to actually attack with the whip, so your reach reverts to 5 ft.
(Since your reach is only 10 ft while you are performing an OA with it.)
Which brings us back to whether or not trigger conditions can be unmet after the effect is triggered.
You guys are arguing that a trigger is met for the OA, then unmet when the reaction is taken (since war caster only replaces the weapon attack of an OA, not the trigger conditions).
We have 2 effects "if A, then B" and "B=C." We are saying that means "if A, then C," you are countering with "no, A does not lead to C."
I disagree. If you are wielding a reach weapon and a creature moves more than 10' from you, you state that you will use your reaction to make an opportunity attack on it with your reach weapon. You may do so, because that is what the rules on reach weapons and opportunity attacks say you can do.
The word "provoke" does not appear in either the rules for reach weapons nor in those for opportunity attacks, only in the rules for the Warcaster feat. And if you are going to cast a spell, then you are not attacking with a reach weapon, so your reach is not increased and it remains 5'.
Are you confusing reach with spell range? We'r not saying the spells range gets increased to 10ft (if it were somehow less than that) for example. Only that you're casting the spell instead of making the opportunity attack. if you were going to make an opportunity attack because the enemy left 10', you instead cast a spell at them.
Edit: As for provoke, an enemy provokes an opportunity attack when: they give you the option to make an opportunity attack.
So "When a hostile creature's movement provokes an opportunity attack from you, you can use your reaction to cast a spell at the creature, rather than making an opportunity attack." means that whenever you are eligible to make an opportunity attack because the enemy moved out of your reach, you are also eligible to instead cast a spell as a reaction. Regardless what your reach is for that opportunity attack is.
I'm probably laughing.
It is apparently so hard to program Aberrant Mind and Clockwork Soul spell-swapping into dndbeyond they had to remake the game without it rather than implement it.
Nicandor, you are blatantly and obviously disagreeing with RAW and RAI. If you have a weapon in hand that you can attack at 10 ft, then moving through that area provokes an AoO. Warcaster lets you replace that AoO with a spell. There is no special wording that you seem to think exists.
If you continue to disagree, please stop hijacking this thread and make your own, with a POLL. I am absolutely sure you will find that the overwhelming population here disagrees with you.
That is OK. You can play as you like. But understand that everyone else will consider you to be house ruling.
P.S. if you do this and the Poll proves you right, I will abase myself in the thread, heaping you with praise.
Not sure where the "reach weapons can't provoke OAs beyond 10 feet" argument came from. That is kind of half the weapon property.
Either reach weapons provoke an OA at 10 feet that can be replaced by warcaster, OR reach weapons don't provoke an OA at 10 feet and therefore can't attack.
Warcaster replaces just the weapon attack that was already triggered by the attack's reach.
Post #14 is the first reference to it in this thread. Apparently you can find a JC tweet that says that's the intent too, though the entry concerning Reach in SAC makes no mention of war caster and vice versa.
Edit: following that logic and the guidance in the SAC, though, then with war caster and a reach weapon, you can never cast a spell as an opportunity attack. The SAC says a creature moving 5'->10' doesn't provoke an opportunity attack with a reach weapon, and moving 10'->15' doesn't allow you to use war caster. (I know there is an idea out there that you have multiple reaches, but that is a bad idea and only matters when you are actually wielding 2 weapons.)
According to that, then not only does this combo not work as intended, it is fundamentally worse than having either parts (reach weapon or war caster) individually.
I will make one last attempt to explain my reasoning and then I am done.
A character has a reach of 5'.
A character holding a reach weapon has a reach of 5'.
A character with a reach weapon gains 5' of additional reach when they attack with it.
A character can make an OA with a reach weapon at 10', because the act of attacking with the reach weapon gives them the required additional reach, per the rules on reach weapons.
A character holding a reach weapon and a dagger has a reach of 5'.
A character holding a reach weapon and a dagger cannot make an OA at 10' with the dagger, because their reach is only 5'.
A character holding a reach weapon and a dagger can make an OA at 10' with the reach weapon, because the act of attacking with with the reach weapon gives them the required additional reach, per the rules on reach weapons.
A character with Warcaster holding a reach weapon has a reach of 5'.
An opponent is 10' away from the Warcaster and moves another 5' away. This does not "provoke" an OA because the opponent did not move out of the reach of the Warcaster, since they did not start within the reach of the Warcaster.
The Warcaster can, however, make an OA at 10' with the reach weapon, because the act of attacking with the reach weapon gives them the required additional reach, per the rules on reach weapons.
Holding a reach weapon does not give you 5' of additional reach. Attacking with it does.
And the problem with your reasoning is the rules for opportunity attacks:
If a character with a reach weapon has a reach of 5, then the attack (presumably with a reach of 10) is not provoked and cannot be made.
OA with weapon: move out of weapon reach triggers weapon attack.
OA with warcaster: move out of weapon reach triggers weapon attack, weapon attack is replaced with spell.
That is one of two things that the reach property does. It also gives you 5' of additional reach when determining your reach for opportunity attacks with it.
So the question is what opportunity attacks can you replace with a spell. Assuming the "with it" in the reach rule is a hard requirement is a bit of a cop out, because it could be just context for the actual weapon the reach property is describing. War Caster makes no caveats, indicating that any opportunity attack can be replaced with a spell. With that being said, these rules are in conflict and neither is more specific than the other (there aren't general tiers of "weapon properties are more specific than feats") so you have to make a ruling.
But that being said, the advice that even Jeremy Crawford has given about reaches is contradictory and the whole topic needs a bit of a cleanup.
I can't tell exactly what your question is, so to explicitly cover every base I can think of:
Did that cover it?
Reach. This weapon adds 5 feet to your reach when you attack with it, as well as when determining your reach for opportunity attacks with it.
Reach explicitly works for OAs.
I will bite one last time. Your reach is increased, either for making an attack, or determining your reach for opportunity attacks with it, when you attack with a reach weapon. If you do not attack with it, you do not get the additional 5' of reach. The wording of reach does not say "when determining your reach for opportunity attacks PERIOD", it says "when determining your reach for opportunity attacks with it." Getting the 5' of additional reach, for either purpose, only happens when you attack with it. Surely no one is suggesting that, if I have a whip in my right hand, I can punch someone 10' away with my left as an OA.
You cannot replace an OA made with a reach weapon at 10' with a spell attack with Warcaster, because if you did, the attack with the reach weapon would not take place, and so your reach would remain 5' and no OA would have been provoked. This is no different than not being able to make an OA at 10' with a non reach weapon, or an unarmed strike, even if you are holding a reach weapon in the other hand.
The requirement for an OA to take place that your opponent move out of your reach does not prevent you from making an OA with a reach weapon at 10' even when your unmodified reach is 5'. The rules on reach weapons explicitly say that, when you make an attack with a reach weapon, or for determining your reach for opportunity attacks with it, you gain 5' of additional reach, so if you make the OA with a reach weapon, your reach is 10' and the conditions for making an OA are met.
Over and out.
No, this is false. Your reach is not increased only when you attack; it is increased when determining your reach for opportunity attacks with the weapon. Actually making the attack is not required. I just gave you the literal, exact definition of reach, which does what I am saying it does and not what you are saying it does. I will repeat the relevant piece here:
"as well as when determining your reach for opportunity attacks with it"
So, for example, suppose you had a magic lantern that lit up whenever you were within reach of a potential OA (maybe it was invented by a wizard who was afraid of polearm-wielding ghosts, I don't know). The lantern would work without any requirement that the OAs actually be made, due to the RAW wording of reach, which I have provided.
This is false, as discussed above. If you need to know your reach for the purposes of an opportunity attack, the reach property explicitly applies, whether or not the attack is made.
Again, false, see above. For example, if you're wielding a magic reach weapon whose enchantment is "anyone who provokes an OA from you while you're wielding this must make a Wisdom save or lose 5 feet of movement", it would happen even if you didn't take the OA. You are correct that reach applies only to the weapon with the property - wielding a glaive doesn't give you Reach on your Unarmed Strikes - but you are otherwise incorrect.
You are exactly right.
No, because you're mischaracterizing how War Caster works. War Caster works when anyone provokes an OA from you, and if you have a reach weapon, someone moving from 10 feet away to 15 feet away from you provokes an OA. It then replaces the attack. It's exactly like how a Tasha's Beast Master can take the Attack action and replace an attack with a Companion order: the attack is replaced after meeting the necessary conditions to perform it.
As another example of your interpretation breaking feats, you're ruling that Polearm Master's second bullet doesn't work at all. As in, it literally does nothing according to you. You're aware of that, right? Because Polearm Master's second bullet reacts to something entering your weapon-augmented reach before you've made the attack in order to let you do something, just like War Caster's third bullet. Tell me honestly, have you ever played under a DM (i.e. not your own rules, literally anyone else's) who agreed with you that Polearm Master's second bullet does literally nothing at all?
Well, they agree with all the things required to trigger the opportunity attack, but not that the trigger applies if the triggered attack is replaced.
By that logic, since opportunity attacks are melee attacks and reach is how far you can target "when making a melee attack." So the 3rd bullet point of war caster must do nothing since all "reach" only applies to melee attacks, so if you are not making a melee attack, no opportunity attack was provoked.
I prefer the RAW of keeping the trigger and replacing the reaction, rather than all replacement effects having to be a valid option for what they are replacing (and therefore doing nothing because why would they be a replacement if they were already a valid option?).
Except you missed a step:
* Decide not to actually attack with the whip, so your reach reverts to 5 ft.
(Since your reach is only 10 ft while you are performing an OA with it.)
Which brings us back to whether or not trigger conditions can be unmet after the effect is triggered.
You guys are arguing that a trigger is met for the OA, then unmet when the reaction is taken (since war caster only replaces the weapon attack of an OA, not the trigger conditions).
We have 2 effects "if A, then B" and "B=C." We are saying that means "if A, then C," you are countering with "no, A does not lead to C."