prepare deprecation of simple and alternative

[jverzani]

This PR does:

• streamlines fzero
• separates out code and tests for alternative_interfaces and simple. (some goes into find_zeros)
• prepares deprecation warnings for functions in alternative_interfaces and simple (but doesn't uncomment them yet)
• add modab code to simple, as it was contributed and might be of independent interest

The goal is to deprecate the two files, both could be elsewhere, especially alternative interfaces which has had comments about it being legacy for years now.

[codecov]

Codecov Report

❌ Patch coverage is 74.55197% with 71 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.04%. Comparing base (a45a34f) to head (f0e482b).
⚠️ Report is 17 commits behind head on master.

Files with missing lines	Patch %	Lines
src/deprecated/simple.jl	14.49%	59 Missing ⚠️
src/Bracketing/false_position.jl	75.00%	5 Missing ⚠️
src/Bracketing/regula_falsi.jl	93.75%	3 Missing ⚠️
src/find_zeros.jl	96.55%	3 Missing ⚠️
src/deprecated/alternative_interfaces.jl	90.90%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #507      +/-   ##
==========================================
- Coverage   86.93%   83.04%   -3.90%     
==========================================
  Files          41       42       +1     
  Lines        2565     2671     +106     
==========================================
- Hits         2230     2218      -12     
- Misses        335      453     +118     

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[Copilot]

Pull request overview

This PR refactors Roots.jl’s “simple” and “alternative interfaces” code paths in preparation for deprecation by moving legacy APIs under src/deprecated/, relocating some implementations (e.g., bisection, dfree) into find_zeros.jl, and updating tests/docs accordingly. It also introduces a new RegulaFalsi bracketing family and adjusts convergence behavior for a new “non-strict bracketing” method category.

Changes:

• Move legacy simple.jl / alternative_interfaces.jl into src/deprecated/ and reorganize tests to match the deprecation plan.
• Add RegulaFalsi implementation and new abstract method categories (AbstractRegulaFalsiMethod, AbstractNonStrictBracketingMethod) with associated convergence/tolerance behavior.
• Update documentation, allocations tests, and test harness ordering (including running Aqua.test_all(Roots) within a @testset), plus a downstream CI workflow.

Reviewed changes

Copilot reviewed 31 out of 32 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
test/test_simple.jl	Consolidates “simple”/legacy interface tests; adds allocation tests for simple APIs.
test/test_newton.jl	Removes duplicated Newton/Halley interface tests now moved elsewhere.
test/test_fzero.jl	Adds regression test for passing a method through fzero.
test/test_find_zeros.jl	Adds tests/benchmarks for dfree and bisection moved under find_zeros.
test/test_find_zero.jl	Removes fzero regression test (relocated to test_fzero.jl).
test/test_derivative_free_interactive.jl	Fixes spelling for “diagnostics” helper naming.
test/test_composable.jl	Adjusts composability tests for bracketing/derivative-free methods.
test/test_bracketing.jl	Expands and restructures bracketing-method test coverage (incl. regula falsi variants).
test/test_allocations.jl	Updates allocation checks to include additional bracketing methods.
test/runtests.jl	Reorders includes, adds Aqua testset, and moves deprecated tests to a “deprecated” section.
src/trace.jl	Updates docs/examples for Tracks() keyword usage.
src/Roots.jl	Moves legacy includes into src/deprecated/ and adjusts exports; includes new bracketing file.
src/find_zeros.jl	Pulls in bisection and dfree implementations for broader use.
src/DerivativeFree/sidi.jl	Adjusts Sidi method initialization and function-call accounting.
src/deprecated/simple.jl	Removes duplicated bisection, adds legacy modab implementation and deprecation stubs.
src/deprecated/alternative_interfaces.jl	Refactors fzero legacy surface API and prepares deprecation points.
src/convergence.jl	Extends convergence checks to support regula falsi / non-strict bracketing categories; tweaks convergence decisions.
src/Bracketing/ridders.jl	Reclassifies Ridders as non-strict bracketing.
src/Bracketing/regula_falsi.jl	Adds new RegulaFalsi method family implementation.
src/Bracketing/modAB.jl	Improves references section in docs.
src/Bracketing/itp.jl	Reclassifies ITP as non-strict bracketing.
src/Bracketing/false_position.jl	Reclassifies FalsePosition under regula falsi umbrella and simplifies reductions.
src/Bracketing/chandrapatlu.jl	Reclassifies Chandrapatla as non-strict bracketing.
src/Bracketing/brent.jl	Reclassifies Brent as non-strict bracketing.
src/Bracketing/bracketing.jl	Adds default tolerances for non-strict bracketing methods.
src/Bracketing/alefeld_potra_shi.jl	Reclassifies Alefeld/Potra/Shi methods as non-strict bracketing.
src/abstract_types.jl	Introduces new abstract method categories for regula falsi and non-strict bracketing.
Project.toml	Bumps version and expands IntervalRootFinding compatibility.
docs/src/roots.md	Edits narrative and doctests to align with updated naming/examples.
docs/src/reference.md	Adds Roots.RegulaFalsi to reference list and updates method tables/descriptions.
docs/src/index.md	Updates package overview text for new/renamed method families.
.github/workflows/downstream.yml	Adds downstream integration test workflow against an external package.

Suppressed comments (3)

src/deprecated/alternative_interfaces.jl:78

• When verbose=true, this currently disables tracking for the default tracks=NullTracks() case, and overwrites user-provided tracks when they pass a non-NullTracks value. This is the opposite of the intended behavior (see the other fzero overloads below).
  src/deprecated/simple.jl:111
• This prepared depwarn line uses the wrong symbol (:a42), which will make the warning harder to filter and inconsistent once uncommented. It should match the function name (:modab).
  test/test_simple.jl:58
• This check is currently not asserted (missing @test), so it won’t catch regressions.

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[Copilot]

Pull request overview

Copilot reviewed 31 out of 32 changed files in this pull request and generated 1 comment.

Suppressed comments (5)

src/find_zeros.jl:134

• dfree(f, xs) assumes xs is indexable and calls length(xs), but the public API (and the docstring example just above) passes a scalar initial guess like dfree(f, 1.0). That will throw a MethodError for length(::Float64) unless xs is normalized to a 1-tuple first.

function dfree(f, xs)
    if length(xs) == 1
        a = float(xs[1])
        fa = f(a)

src/deprecated/simple.jl:29

• The planned deprecation message for a42 points users to Roots.AlefeldPotraShi(), but a42 corresponds to Roots.A42() (as referenced in this file’s docstring). The message will be misleading once depwarns are enabled.

This issue also appears in the following locations of the same file:

• line 109
• line 320
  src/deprecated/simple.jl:112

• The planned deprecation warning for modab uses the symbol :a42, which would attribute the warning to the wrong binding. This should match the deprecated function name (e.g. :modab).
  src/deprecated/simple.jl:330
• The planned deprecation warning for muller references Roots.Muller(), but there is no Muller method type in the codebase (only the muller function in this deprecated file). If/when depwarns are enabled, this message will direct users to a non-existent API.
  src/convergence.jl:220
• Docstring bullet formatting: * :exact_zero renders oddly in Markdown (the `:` is outside the code span). It should be `* `:exact_zero to match the other bullets.

If algorithm has stopped or converged, return flag and `true`. Flags are:

* :`exact_zero` if `|f(xn1)| == 0`

* `:x_converged` if `xn1 ≈ xn`, typically with non-zero tolerances specified.