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fix: erratic stack overflow in infer.rs (live_var) #638

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merged 7 commits into from
Nov 7, 2023
Merged

fix: erratic stack overflow in infer.rs (live_var) #638

merged 7 commits into from
Nov 7, 2023

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acl-cqc
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@acl-cqc acl-cqc commented Nov 2, 2023 •
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closes #633

  • Add test case. Reduced this to a 2-node DFG (plus Input and Output). That this hasn't been showing up repeatedly in other tests - I put down to Custom operations implicitly require their extension #388: most custom ops have empty extension_reqs so do not generate Plus constraints.
  • Run (50%-failing) test 10 times -> failure rate ~~ 1 in 2^10
  • Fix calculation of live_vars and live_metas by one-off traversal of constraints+solutions in fn results().

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codecov bot commented Nov 3, 2023 •
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Codecov Report

Merging #638 (97b265f) into main (57270d5) will increase coverage by 0.05%.
The diff coverage is 92.30%.

❗ Current head 97b265f differs from pull request most recent head 89b45ed. Consider uploading reports for the commit 89b45ed to get more accurate results

@@            Coverage Diff             @@
##             main     #638      +/-   ##
==========================================
+ Coverage   79.22%   79.28%   +0.05%     
==========================================
  Files          64       64              
  Lines       11314    11352      +38     
  Branches    11314    11352      +38     
==========================================
+ Hits         8964     9000      +36     
+ Misses       1713     1711       -2     
- Partials      637      641       +4
Files Coverage Δ
src/extension/infer.rs 86.58% <92.30%> (+0.29%) ⬆️

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@acl-cqc acl-cqc removed the request for review from ss2165 November 3, 2023 09:49
acl-cqc
acl-cqc commented Nov 3, 2023
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src/extension/infer.rs Outdated
// If it depends on some other live meta, that's bad news.
return Err(InferExtensionError::Unsolved { location: *loc });
}
// If it only depends on graph variables, then we don't have
// If it ("only"??) depends on graph variables, then we don't have
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This only is what bothers me; the above calculation includes things that depend on both graph variables and other things.

See branch fix/infer_stack_overflow2 for a simpler check that things depend upon solved values are solved; but (step through the commits) this is basically pointless.

See branch fix/infer_stack_overflow3 for a more-complex check. Upon reflection I think maybe that is what's wanted?

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Yes good point, the logic wasn't checking the "only" part before

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Any thoughts as to which of these is "right" ?

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I think the "only" can be removed. All the comment is saying is that we can't find a solution as long as this meta depends on a variable.

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@acl-cqc acl-cqc Nov 6, 2023 •
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So if we have a Meta with two constraints: Plus({Ext}, Meta1) and Plus({Ext2}, V) where Meta1 has a concrete solution and V is the graph variable...we should avoid solving it? (Rather than just computing {Ext} union solution-of-Meta1) Is that because solving it now mean we lose the ability to check the graph variable provides the same solution?

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If so, then yes, I'll remove the "only", and to be honest, the assert below seems pretty pointless now too (it exactly repeats the two if-conditions inside this loop over the same self.extensions).

I was thinking maybe the "only" was genuine, and if we can compute a solution without the variables, then we should - in which case branch fix/infer_stack_overflow3

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So if we have a Meta with two constraints: Plus({Ext}, Meta1) and Plus({Ext2}, V) where Meta1 has a concrete solution and V is the graph variable...we should avoid solving it?

I think in that case we would've found the solution (Ext + get_solution(Meta1)) in main_loop, and would skip this step on that meta because a solution exists for it

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Ah, good point, yes thanks. Ok, will update comment + assert

croyzor
croyzor reviewed Nov 7, 2023
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src/extension/infer.rs Outdated
let mut results: ExtensionSolution = HashMap::new();
for (loc, meta) in self.extensions.iter() {
if let Some(rs) = self.get_solution(meta) {
if loc.1 == Direction::Incoming {
results.insert(loc.0, rs.clone());
}
} else if self.live_var(meta).is_some() {
} else if !depends_on_var.contains(&self.resolve(*meta)) {
// If it depends on some other live meta, that's bad news.
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This comment needs updating, since the one explaining what "live var" means is gone!

@acl-cqc acl-cqc added this pull request to the merge queue Nov 7, 2023
Merged via the queue into main with commit b7ebb0d Nov 7, 2023
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@acl-cqc acl-cqc deleted the fix/infer_stack_overflow branch November 7, 2023 09:45
@github-actions github-actions bot mentioned this pull request Jan 3, 2024
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github-merge-queue bot pushed a commit that referenced this pull request Jan 15, 2024
@github-actions @aborgna-q
chore: release v0.1.0 (#766)
9e71c89 
## 🤖 New release
* `quantinuum-hugr`: 0.1.0

<details><summary><i><b>Changelog</b></i></summary><p>

<blockquote>

## 0.1.0 (2024-01-15)

### Bug Fixes

- Subgraph boundaries with copies
([#440](#440))
- [**breaking**] Use internal tag for SumType enum serialisation
([#462](#462))
- Check kind before unwrap in insert_identity
([#475](#475))
- Allow for variables to get solved in inference
([#478](#478))
- In IdentityInsertion add noop to correct parent
([#477](#477))
- Failing release tests ([#485](#485))
- [**breaking**] Serialise `Value`, `PrimValue`, and `TypeArg` with
internal tags ([#496](#496))
- Serialise custom constants with internal tag
([#502](#502))
- [**breaking**] Reduce max int width in arithmetic extension to 64
([#504](#504))
- HugrView::get_function_type
([#507](#507))
- TODO in resolve_extension_ops: copy across input_extensions
([#510](#510))
- Use given input extensions in `define_function`
([#524](#524))
- Lessen requirements for hugrs in outline_cfg
([#528](#528))
- Make unification logic less strict
([#538](#538))
- Simple replace incorrectly copying metadata
([#545](#545))
- Account for self-referencial constraints
([#551](#551))
- Consider shunted metas when comparing equality
([#555](#555))
- Join labels in issue workflow
([#563](#563))
- Comment out broken priority code
([#562](#562))
- Handling of issues with no priority label
([#573](#573))
- Don't insert temporary wires when extracting a subgraph
([#582](#582))
- Improve convexity checking and fix test
([#585](#585))
- Ignore input->output links in
SiblingSubgraph::try_new_dataflow_subgraph
([#589](#589))
- Enforce covariance of SiblingMut::RootHandle
([#594](#594))
- Erratic stack overflow in infer.rs (live_var)
([#638](#638))
- Work harder in variable instantiation
([#591](#591))
- Actually add the error type to prelude
([#672](#672))
- Serialise dynamically computed opaqueOp signatures
([#690](#690))
- FuncDefns don't require that their extensions match their children
([#688](#688))
- Binary compute_signature returning a PolyFuncType with binders
([#710](#710))
- Use correct number of args for int ops
([#723](#723))
- [**breaking**] Add serde tag to TypeParam enum
([#722](#722))
- Allow widening and narrowing to same width.
([#735](#735))
- Case node should not have an external signature
([#749](#749))
- [**breaking**] Normalize input/output value/static/other ports in
`OpType` ([#783](#783))
- No dataflow_signature for block types
([#792](#792))
- Ignore unsupported test in miri
([#794](#794))
- Include schema rather than read file
([#807](#807))

### Documentation

- Add operation constraint to quantum extension
([#543](#543))
- Coverage check section in DEVELOPMENT.md
([#648](#648))
- Remove "quantum extension" from HUGR spec.
([#694](#694))
- Improve crate-level docs, including example code.
([#698](#698))
- Spec cleanups and clarifications
([#742](#742))
- Spec clarifications ([#738](#738))
- Spec updates ([#741](#741))
- [spec] Remove references to causal cone and Order edges from Input
([#762](#762))
- Mention experimental inference in readme
([#800](#800))
- Collection of spec updates for 0.1
([#801](#801))
- Add schema v0 ([#805](#805))
- Update spec wrt. polymorphism
([#791](#791))

### Features

- Derive things for builder structs
([#229](#229))
- Return a slice of types from the signature
([#238](#238))
- Move `dot_string` to `HugrView`
([#271](#271))
- [**breaking**] Change `TypeParam::USize` to `TypeParam::BoundedNat`
and use in int extensions
([#445](#445))
- TKET2 compatibility requirements
([#450](#450))
- Split methods between `HugrMut` and `HugrMutInternals`
([#441](#441))
- Add `HugrView::node_connections` to get all links between nodes
([#460](#460))
- Location information in extension inference error
([#464](#464))
- Add T, Tdg, X gates ([#466](#466))
- [**breaking**] Add `ApplyResult` associated type to `Rewrite`
([#472](#472))
- Implement rewrite `IdentityInsertion`
([#474](#474))
- Instantiate inferred extensions
([#461](#461))
- Default DFG builders to open extension sets
([#473](#473))
- Some helper methods ([#482](#482))
- Extension inference for conditional nodes
([#465](#465))
- Add ConvexChecker ([#487](#487))
- Add clippy lint for mut calls in a debug_assert
([#488](#488))
- Default more builder methods to open extension sets
([#492](#492))
- Port is serializable ([#489](#489))
- More general portgraph references
([#494](#494))
- Add extension deltas to CFG ops
([#503](#503))
- Implement petgraph traits on Hugr
([#498](#498))
- Make extension delta a parameter of CFG builders
([#514](#514))
- [**breaking**] SiblingSubgraph does not borrow Hugr
([#515](#515))
- Validate TypeArgs to ExtensionOp
([#509](#509))
- Derive Debug & Clone for `ExtensionRegistry`.
([#530](#530))
- Const nodes are built with some extension requirements
([#527](#527))
- Some python errors and bindings
([#533](#533))
- Insert_hugr/insert_view return node map
([#535](#535))
- Add `SiblingSubgraph::try_from_nodes_with_checker`
([#547](#547))
- PortIndex trait for undirected port parameters
([#553](#553))
- Insert/extract subgraphs from a HugrView
([#552](#552))
- Add `new_array` operation to prelude
([#544](#544))
- Add a `DataflowParentID` node handle
([#559](#559))
- Make TypeEnum and it's contents public
([#558](#558))
- Optional direction check when querying a port index
([#566](#566))
- Extension inference for CFGs
([#529](#529))
- Better subgraph verification errors
([#587](#587))
- Compute affected nodes for `SimpleReplacement`
([#600](#600))
- Move `SimpleReplace::invalidation_set` to the `Rewrite` trait
([#602](#602))
- [**breaking**] Resolve extension ops (mutating Hugr) in
(infer_and_->)update_validate
([#603](#603))
- Add accessors for node index and const values
([#605](#605))
- [**breaking**] Expose the value of ConstUsize
([#621](#621))
- Nicer debug and display for core types
([#628](#628))
- [**breaking**] Static checking of Port direction
([#614](#614))
- Builder and HugrMut add_op_xxx default to open extensions
([#622](#622))
- [**breaking**] Add panicking integer division ops
([#625](#625))
- Add hashable `Angle` type to Quantum extension
([#608](#608))
- [**breaking**] Remove "rotations" extension.
([#645](#645))
- Port.as_directed to match on either direction
([#647](#647))
- Impl GraphRef for PetgraphWrapper
([#651](#651))
- Provide+implement Replace API
([#613](#613))
- Require the node's metadata to always be a Map
([#661](#661))
- [**breaking**] Polymorphic function types (inc OpDefs) using dyn trait
([#630](#630))
- Make prelude error type public
([#669](#669))
- Shorthand for retrieving custom constants from `Const`, `Value`
([#679](#679))
- [**breaking**] HugrView API improvements
([#680](#680))
- Make FuncDecl/FuncDefn polymorphic
([#692](#692))
- [**breaking**] Simplify `SignatureFunc` and add custom arg validation.
([#706](#706))
- [**breaking**] Drop the `pyo3` feature
([#717](#717))
- [**breaking**] `OpEnum` trait for common opdef functionality
([#721](#721))
- MakeRegisteredOp trait for easier registration
([#726](#726))
- Getter for `PolyFuncType::body`
([#727](#727))
- `Into<OpType>` for custom ops
([#731](#731))
- Always require a signature in `OpaqueOp`
([#732](#732))
- Values (and hence Consts) know their extensions
([#733](#733))
- [**breaking**] Use ConvexChecker trait
([#740](#740))
- Custom const for ERROR_TYPE
([#756](#756))
- Implement RemoveConst and RemoveConstIgnore
([#757](#757))
- Constant folding implemented for core and float extension
([#769](#769))
- Constant folding for arithmetic conversion operations
([#720](#720))
- DataflowParent trait for getting inner signatures
([#782](#782))
- Constant folding for logic extension
([#793](#793))
- Constant folding for list operations
([#795](#795))
- Add panic op to prelude
([#802](#802))
- Const::from_bool function
([#803](#803))

### HugrMut

- Validate nodes for set_metadata/get_metadata_mut, too
([#531](#531))

### HugrView

- Validate nodes, and remove Base
([#523](#523))

### Miscellaneous Tasks

- [**breaking**] Update portgraph 0.10 and pyo3 0.20
([#612](#612))
- [**breaking**] Hike MSRV to 1.75
([#761](#761))

### Performance

- Use lazy static definittion for prelude registry
([#481](#481))

### Refactor

- Move `rewrite` inside `hugr`, `Rewrite` -> `Replace` implementing new
'Rewrite' trait ([#119](#119))
- Use an excluded upper bound instead of max log width.
([#451](#451))
- Add extension info to `Conditional` and `Case`
([#463](#463))
- `ExtensionSolution` only consists of input extensions
([#480](#480))
- Remove builder from more DFG tests
([#490](#490))
- Separate hierarchy views
([#500](#500))
- [**breaking**] Use named struct for float constants
([#505](#505))
- Allow NodeType::new to take any Into<Option<ExtensionSet>>
([#511](#511))
- Move apply_rewrite from Hugr to HugrMut
([#519](#519))
- Use SiblingSubgraph in SimpleReplacement
([#517](#517))
- CFG takes a FunctionType
([#532](#532))
- Remove check_custom_impl by inlining into check_custom
([#604](#604))
- Insert_subgraph just return HashMap, make InsertionResult new_root
compulsory ([#609](#609))
- [**breaking**] Rename predicate to TupleSum/UnitSum
([#557](#557))
- Simplify infer.rs/report_mismatch using early return
([#615](#615))
- Move the core types to their own module
([#627](#627))
- Change &NodeType->&OpType conversion into op() accessor
([#623](#623))
- Infer.rs 'fn results' ([#631](#631))
- Be safe ([#637](#637))
- NodeType constructors, adding new_auto
([#635](#635))
- Constraint::Plus stores an ExtensionSet, which is a BTreeSet
([#636](#636))
- [**breaking**] Remove `SignatureDescription`
([#644](#644))
- [**breaking**] Remove add_op_<posn> by generalizing add_node_<posn>
with "impl Into" ([#642](#642))
- Rename accidentally-changed Extension::add_node_xxx back to add_op
([#659](#659))
- [**breaking**] Remove quantum extension
([#670](#670))
- Use type schemes in extension definitions wherever possible
([#678](#678))
- [**breaking**] Flatten `Prim(Type/Value)` in to parent enum
([#685](#685))
- [**breaking**] Rename `new_linear()` to `new_endo()`.
([#697](#697))
- Replace NodeType::signature() with io_extensions()
([#700](#700))
- Validate ExtensionRegistry when built, not as we build it
([#701](#701))
- [**breaking**] One way to add_op to extension
([#704](#704))
- Remove Signature struct
([#714](#714))
- Use `MakeOpDef` for int_ops
([#724](#724))
- [**breaking**] Use enum op traits for floats + conversions
([#755](#755))
- Avoid dynamic dispatch for non-folding operations
([#770](#770))
- Simplify removeconstignore verify
([#768](#768))
- [**breaking**] Unwrap BasicBlock enum
([#781](#781))
- Make clear const folding only for leaf ops
([#785](#785))
- [**breaking**] `s/RemoveConstIgnore/RemoveLoadConstant`
([#789](#789))
- Put extension inference behind a feature gate
([#786](#786))

### SerSimpleType

- Use Vec not TypeRow ([#381](#381))

### SimpleReplace+OutlineCfg

- Use HugrMut methods rather than .hierarchy/.graph
([#280](#280))

### Testing

- Update inference test to not use DFG builder
([#550](#550))
- Strengthen "failing_sccs_test", rename to "sccs" as it's not failing!
([#660](#660))
- [**breaking**] Improve coverage in signature and validate
([#643](#643))
- Use insta snapshots to add dot_string coverage
([#682](#682))
- Miri ignore file-opening test
([#684](#684))
- Unify the serialisation tests
([#730](#730))
- Add schema validation to roundtrips
([#806](#806))

### `ConstValue

- :F64` and `OpaqueOp::new`
([#206](#206))

### Cleanup

- Remove outdated comment
([#536](#536))

### Cosmetic

- Format + remove stray TODO
([#444](#444))

### Doc

- Crate name as README title + add reexport
([#199](#199))

### S/EdgeKind

- :Const/EdgeKind::Static/
([#201](#201))

### Simple_replace.rs

- Use HugrMut::remove_node, includes clearing op_types
([#242](#242))

### Spec

- Remove "Draft 3" from title of spec document.
([#590](#590))
- Rephrase confusing paragraph about TailLoop inputs/outputs
([#567](#567))

### Src/ops/validate.rs

- Common-up some type row calculations
([#254](#254))
</blockquote>


</p></details>

---
This PR was generated with
[release-plz](https://github.com/MarcoIeni/release-plz/).

---------

Signed-off-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Agustín Borgna <121866228+aborgna-q@users.noreply.github.com>
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Erratic stack overflow in infer.rs 'live_vars'
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