Add UnnecessarySubstring for regions parsed via Integer.parseInt. - #6000
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gaul wants to merge 1 commit into
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Add UnnecessarySubstring for regions parsed via Integer.parseInt.#6000gaul wants to merge 1 commit into
UnnecessarySubstring for regions parsed via Integer.parseInt.#6000gaul wants to merge 1 commit into
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`Integer.parseInt(String)` and its siblings force callers to materialize the region they parse. Since JDK 9 each has a `(CharSequence, int, int, int)` overload that reads the region in place, so the copy is pure overhead. Covers the four parses that have that overload: `Integer.parseInt`, `Integer.parseUnsignedInt`, `Long.parseLong` and `Long.parseUnsignedLong`. `Double.parseDouble`, `Integer.valueOf` and `Integer.decode` have none. The overload is resolved on the owning symbol rather than inferred from the source level, so `--release 8` compilations report nothing. `s.substring(begin)` needs `s.length()` in the replacement, which repeats the target, so that form is only rewritten when the target is an identifier, a literal, or a side-effect-free field or array access. Run over sources jars for ~100 widely used Maven Central artifacts (54,690 files), this reports 100 occurrences in 18 of them, including commons-lang3, h2, hsqldb, lucene-core and jgit.
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Integer.parseInt(String)and its siblings force callers to materialize the region they parse. Since JDK 9 each has a(CharSequence, int, int, int)overload that reads the region in place, so the copy is pure overhead.Covers the four parses that have that overload:
Integer.parseInt,Integer.parseUnsignedInt,Long.parseLongandLong.parseUnsignedLong.Double.parseDouble,Integer.valueOfandInteger.decodehave none. The overload is resolved on the owning symbol rather than inferred from the source level, so--release 8compilations report nothing.s.substring(begin)needss.length()in the replacement, which repeats the target, so that form is only rewritten when the target is an identifier, a literal, or a side-effect-free field or array access.Run over sources jars for ~100 widely used Maven Central artifacts (54,690 files), this reports 100 occurrences in 18 of them, including commons-lang3, h2, hsqldb, lucene-core and jgit.