NEWS.md
In minex: Automatically Reduce Failing R Scripts to a Minimal Reproducible Example

minex 0.2.0

explain_failure() sends a minex() result to an LLM (via the suggested ellmer package), returning a structured explanation of why it fails, a proposed fix (verified by executing it), a paste-ready bug report, and a diagnosis. Provider-agnostic: works with any ellmer-supported backend (OpenAI, Anthropic, Ollama, OpenRouter, etc.).
minex(granularity = "expression") reduces within a statement, isolating a failing pipeline stage (|>/%>%) or positional call argument via Hierarchical Delta Debugging (HDD*).
minex() now retries at granularity = "expression" when statement-level reduction removes nothing, instead of returning the input unchanged. This is the usual outcome for a script that is one function definition plus a call: every top-level statement is load-bearing, but the failure is nested inside the function body where statement bisection cannot reach it. Measured on 61 such scripts, the share that reduce at all went from 10/61 to 61/61, removing a median 47% of characters. The retried result carries escalated_from = "statement" and coarse_oracle_calls, and its code is a simplification of the original statements rather than a subset of them. Pass granularity = "statement" explicitly for statement-level reduction only. max_oracle_calls still bounds the whole call -- the second pass runs on what the first left -- and no retry happens when the statement pass stopped early against that budget.
Input that does not parse now raises a classed condition, c("minex_parse_error", "minex_error"), preserving R's parser diagnostic in both the message and a parse_error field. Callers that feed minex() machine-generated code can branch on the class rather than matching against the text of a parser message.
print() on a result leads with whichever axis actually moved. A run that removed characters but no whole statements previously headlined "3 statement(s) reduced to 3", reporting a successful reduction as a failure. When nothing moved at statement granularity, the note now names granularity = "expression".
The result gains n_chars_original and n_chars_minimal (character counts of the code before and after reduction) and a granularity field recording which mode produced the result.
minex() can target warnings and messages, not just errors, via condition.
Failure-point truncation drops statements after the failure for free.
max_oracle_calls bounds the search; incomplete results are labelled complete = FALSE, print a note, and emit a warning.
New algorithm = "cdd" (Counting-based Delta Debugging, Zhang et al. 2025) alongside the classic "ddmin". "cdd" is now the default algorithm for minex(), ddmin(), and reduce_rows(); the classic "ddmin" block- halving loop remains available via algorithm = "ddmin".
match now also accepts a function for custom condition matching.
minex(clipboard = TRUE) reads the script from the system clipboard (requires the suggested clipr package).

Bug fixes:

ddmin() (and minex()/reduce_rows()) now return the smallest confirmed subset when max_oracle_calls is exhausted mid-reduction, instead of the whole input.
oracle_calls now includes the one-off failure-point truncation probe, so the reported count reflects every predicate evaluation.
granularity = "expression" now drops any statement left redundant by sub-expression reduction, keeping the result statement-minimal.
Fixed a case under the in-process backend where a script that recovered from a warning promoted to an error via options(warn = 2) and then failed for a different reason could record the wrong failure.

minex 0.1.0

Initial release.
minex() reduces a failing R script to a one-minimal reproducible example, evaluating candidates in a separate R process by default.
ddmin() exposes the underlying delta debugging algorithm for reuse on any collection.
reduce_rows() reduces a data frame to the rows that reproduce a failure.