perf: rewrite decimal-to-integer cast predicates as source-domain ranges

[discord9]

Which issue does this PR close?

• Closes #. (Upstream report: A filter on CAST(decimal AS BIGINT) returns wrong rows: the planner rewrites it to an exact decimal comparison spiceai/spiceai#14969 — tracked downstream; no apache/datafusion issue was filed for it yet.)

Stacked on #22906 (1e127365510c83cfffec5fed6f72a56b5875d5b0); please review/merge that one first. The wrong-rows regression itself is fixed by #22906's allowlist; this PR adds the optimization on top.

Rationale for this change

CAST(decimal_col AS BIGINT) = 173665 is a many-to-one comparison (decimal→integer truncates toward zero), so #22906 correctly refuses to fold it and keeps the cast on the column. That is correct but leaves performance on the table: the predicate cannot be pushed into min/max statistics or bloom pruning, and every row pays the cast.

The same predicate has an exact source-domain form: price >= 173665.00 AND price < 173666.00. Rewriting to that bucket keeps identical results while removing the cast and enabling pruning.

What changes are included in this PR?

• datafusion/expr-common/src/casts.rs: new decimal-to-integer CastPredicatePreimage::Range for Decimal128(p, s) sources with s > 0 (one level of Dictionary unwrapped). CAST(col AS INT) OP literal rewrites to source-domain decimal bounds using the same truncation-toward-zero buckets as timestamp precision narrowing (v > 0 → [v·10^s, (v+1)·10^s), v == 0 → [1-10^s, 10^s), v < 0 → [(v-1)·10^s+1, v·10^s+1)). trunc_toward_zero_bucket generalized i64 → i128 and reused; no second bucket implementation. Bounds use checked i128 arithmetic validated against the source precision: any unrepresentable bound retains the cast. Decimal32/64/256, scale 0, and non-integer literals are out of scope. No exact preimage can be produced for decimal→int (is_exact_cast_safe still rejects it), so IN lists are untouched.
• datafusion/sqllogictest/test_files/simplify_expr.slt: end-to-end cases on the spiceai#14969 dataset (8 rows), including = 173665 → rows 2–5, strict/non-strict ranges, negative and zero buckets, NULL-row semantics for IS [NOT] DISTINCT FROM and !=, EXPLAIN plans showing the source-domain rewrite, and the retained-cast case for an unrepresentable bucket.
• Logical (optimizer) and physical (physical-expr) consumers already dispatch Range preimages and guard volatile-input duplication, so they are unchanged.

What is the testing strategy for this PR?

• cargo test -p datafusion-expr-common --lib: 239 passed, including 7 new unit tests for bucket bounds per sign, all operators, unrepresentable-bound rejection, scale-0 rejection, Dictionary sources, Decimal256 rejection, out-of-range literal rejection.
• cargo test -p datafusion-optimizer --lib (928) and cargo test -p datafusion-physical-expr --lib (1695, 2 ignored): pass.
• cargo test -p datafusion-sqllogictest --test sqllogictests -- simplify_expr: pass.
• cargo fmt --all --check, cargo clippy -p datafusion-expr-common --all-targets -- -D warnings, git diff --check: pass.

Are there any user-facing changes?

Performance: predicates comparing CAST(decimal AS integer) to integer literals are now rewritten to source-domain decimal ranges, removing the per-row cast and enabling min/max and bloom pruning. Result sets are unchanged relative to this PR's base (#22906).

For values whose cast would error (out of target integer range), the rewritten predicate evaluates to a Boolean instead of erroring, matching the already-accepted overflow policy of the timestamp range preimages; this is documented on the new function. No API changes.

[github-actions]

Thank you for opening this pull request!

Reviewer note: cargo-semver-checks reported the current version number is not SemVer-compatible with the changes in this pull request (compared against the base branch).

Details

     Cloning apache/main
    Building datafusion v55.1.0 (current)
       Built [  57.771s] (current)
     Parsing datafusion v55.1.0 (current)
      Parsed [   0.032s] (current)
    Building datafusion v55.1.0 (baseline)
       Built [  57.121s] (baseline)
     Parsing datafusion v55.1.0 (baseline)
      Parsed [   0.033s] (baseline)
    Checking datafusion v55.1.0 -> v55.1.0 (no change; assume patch)
     Checked [   0.640s] 223 checks: 223 pass, 31 skip
     Summary no semver update required
    Finished [ 117.507s] datafusion
    Building datafusion-expr-common v55.1.0 (current)
       Built [  19.393s] (current)
     Parsing datafusion-expr-common v55.1.0 (current)
      Parsed [   0.018s] (current)
    Building datafusion-expr-common v55.1.0 (baseline)
       Built [  18.881s] (baseline)
     Parsing datafusion-expr-common v55.1.0 (baseline)
      Parsed [   0.018s] (baseline)
    Checking datafusion-expr-common v55.1.0 -> v55.1.0 (no change; assume patch)
     Checked [   0.222s] 223 checks: 222 pass, 1 fail, 0 warn, 31 skip

--- failure function_marked_deprecated: function #[deprecated] added ---

Description:
A function is now #[deprecated]. Downstream crates will get a compiler warning when using this function.
        ref: https://doc.rust-lang.org/reference/attributes/diagnostics.html#the-deprecated-attribute
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.50.0/src/lints/function_marked_deprecated.ron

Failed in:
  function datafusion_expr_common::casts::is_date_narrowing_cast in /home/runner/work/datafusion/datafusion/datafusion/expr-common/src/casts.rs:827

     Summary semver requires new minor version: 0 major and 1 minor checks failed
    Finished [  39.603s] datafusion-expr-common
    Building datafusion-optimizer v55.1.0 (current)
       Built [  25.177s] (current)
     Parsing datafusion-optimizer v55.1.0 (current)
      Parsed [   0.031s] (current)
    Building datafusion-optimizer v55.1.0 (baseline)
       Built [  25.136s] (baseline)
     Parsing datafusion-optimizer v55.1.0 (baseline)
      Parsed [   0.032s] (baseline)
    Checking datafusion-optimizer v55.1.0 -> v55.1.0 (no change; assume patch)
     Checked [   0.165s] 223 checks: 223 pass, 31 skip
     Summary no semver update required
    Finished [  51.370s] datafusion-optimizer
    Building datafusion-physical-expr v55.1.0 (current)
       Built [  27.452s] (current)
     Parsing datafusion-physical-expr v55.1.0 (current)
      Parsed [   0.046s] (current)
    Building datafusion-physical-expr v55.1.0 (baseline)
       Built [  27.181s] (baseline)
     Parsing datafusion-physical-expr v55.1.0 (baseline)
      Parsed [   0.049s] (baseline)
    Checking datafusion-physical-expr v55.1.0 -> v55.1.0 (no change; assume patch)
     Checked [   0.338s] 223 checks: 223 pass, 31 skip
     Summary no semver update required
    Finished [  55.997s] datafusion-physical-expr
    Building datafusion-sqllogictest v55.1.0 (current)
       Built [  93.054s] (current)
     Parsing datafusion-sqllogictest v55.1.0 (current)
      Parsed [   0.015s] (current)
    Building datafusion-sqllogictest v55.1.0 (baseline)
       Built [  92.949s] (baseline)
     Parsing datafusion-sqllogictest v55.1.0 (baseline)
      Parsed [   0.016s] (baseline)
    Checking datafusion-sqllogictest v55.1.0 -> v55.1.0 (no change; assume patch)
     Checked [   0.108s] 223 checks: 223 pass, 31 skip
     Summary no semver update required
    Finished [ 188.942s] datafusion-sqllogictest

[codecov-commenter]

Codecov Report

❌ Patch coverage is 95.08671% with 85 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.83%. Comparing base (55b2f09) to head (3ab2233).
⚠️ Report is 34 commits behind head on main.

Files with missing lines	Patch %	Lines
datafusion/expr-common/src/casts.rs	94.63%	34 Missing and 20 partials ⚠️
...ptimizer/src/simplify_expressions/cast_preimage.rs	95.65%	12 Missing and 4 partials ⚠️
...fusion/physical-expr/src/simplifier/unwrap_cast.rs	96.74%	8 Missing and 3 partials ⚠️
...imizer/src/simplify_expressions/expr_simplifier.rs	81.81%	0 Missing and 2 partials ⚠️
datafusion/physical-expr/src/simplifier/mod.rs	66.66%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #26216      +/-   ##
==========================================
+ Coverage   82.74%   82.83%   +0.08%     
==========================================
  Files        1147     1149       +2     
  Lines      449755   453468    +3713     
  Branches   449755   453468    +3713     
==========================================
+ Hits       372168   375629    +3461     
- Misses      54915    55015     +100     
- Partials    22672    22824     +152     

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