strings: factor trim into a parameterised strip facility - #9140
Open
tautschnig wants to merge 1 commit into
Open
strings: factor trim into a parameterised strip facility#9140tautschnig wants to merge 1 commit into
tautschnig wants to merge 1 commit into
Conversation
Refactor add_axioms_for_trim into a thin wrapper over a new generic add_axioms_for_strip(str, res, is_strippable, strip_front, strip_back, result_type): remove a maximal run of `is_strippable` characters from the selected end(s). Java trim instantiates it with its `c <= ' '` predicate on both ends; behaviour-preserving. The parameterisation lets other strip-family operations share one axiom set instead of near-duplicating it: a different character predicate (e.g. Java 11's String.strip family uses the Character.isWhitespace set, which KEEPS control bytes below 0x20 that trim strips, so it cannot reuse trim) and one-sided stripping (stripLeading / stripTrailing) become instantiations rather than new axiom code. Verified: [strings] unit green; regression/strings green; jbmc-strings green (Java trim behaviour unchanged). Co-authored-by: Kiro <kiro-agent@users.noreply.github.com>
tautschnig
requested review from
kroening,
martin-cs and
peterschrammel
as code owners
July 28, 2026 20:01
There was a problem hiding this comment.
Pull request overview
Note
Copilot couldn't run its full agentic review because it didn't start before the timeout. Make sure your repository has a runner available, or add a copilot-code-review.yml file specifying one with the runs-on attribute. See the docs for more details.
Refactors Java trim constraint generation by introducing a generic, parameterised add_axioms_for_strip that can express trim-like “strip runs from ends” behaviors via a character predicate and end-selection flags.
Changes:
- Replaced the bespoke
add_axioms_for_trimaxiom set with a thin wrapper around a new generic strip axiom generator. - Added
string_constraint_generatort::add_axioms_for_strip(...)with predicate + (front/back) configuration to share logic across strip-family operations.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.
| File | Description |
|---|---|
| src/solvers/strings/string_constraint_generator_transformation.cpp | Implements add_axioms_for_strip and rewrites add_axioms_for_trim to call it. |
| src/solvers/strings/string_constraint_generator.h | Declares the new add_axioms_for_strip API and adjusts includes for std::function. |
💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.
Comment on lines
+265
to
+278
| // Maximality: either the result is empty (idx == |str|), or the kept | ||
| // boundary characters are non-strippable (so all leading/trailing | ||
| // strippable characters were removed). | ||
| exprt non_strip = static_cast<exprt>(true_exprt{}); | ||
| if(strip_front) | ||
| non_strip = and_exprt(non_strip, not_exprt(is_strippable(str[idx]))); | ||
| if(strip_back) | ||
| { | ||
| const exprt last = | ||
| minus_exprt(plus_exprt(idx, res_len), from_integer(1, index_type)); | ||
| non_strip = and_exprt(non_strip, not_exprt(is_strippable(str[last]))); | ||
| } | ||
| constraints.existential.push_back( | ||
| or_exprt(equal_exprt(idx, str_len), non_strip)); |
Comment on lines
+265
to
+267
| // Maximality: either the result is empty (idx == |str|), or the kept | ||
| // boundary characters are non-strippable (so all leading/trailing | ||
| // strippable characters were removed). |
Codecov Report❌ Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## develop #9140 +/- ##
========================================
Coverage 80.83% 80.83%
========================================
Files 1715 1715
Lines 189957 189985 +28
Branches 73 73
========================================
+ Hits 153549 153572 +23
- Misses 36408 36413 +5 ☔ View full report in Codecov by Harness. 🚀 New features to boost your workflow:
|
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Refactor add_axioms_for_trim into a thin wrapper over a new generic add_axioms_for_strip(str, res, is_strippable, strip_front, strip_back, result_type): remove a maximal run of
is_strippablecharacters from the selected end(s). Java trim instantiates it with itsc <= ' 'predicate on both ends; behaviour-preserving.The parameterisation lets other strip-family operations share one axiom set instead of near-duplicating it: a different character predicate (e.g. Java 11's String.strip family uses the Character.isWhitespace set, which KEEPS control bytes below 0x20 that trim strips, so it cannot reuse trim) and one-sided stripping (stripLeading / stripTrailing) become instantiations rather than new axiom code.
Verified: [strings] unit green; regression/strings green; jbmc-strings green (Java trim behaviour unchanged).