Fix bug in mb_get_substr_slow (sometimes outputs wrong number of characters) #12983
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…acters) Thanks to Maurício Fauth for finding and reporting this bug. The bug was introduced in October 2022. It originally only affected text encodings which do not have a fixed byte width per characters and for which mbstring does not have an mblen_table. However, I recently made another change to mbstring, such that mb_substr no longer relies on the mblen_table even if one is available. Because of this change, the bug earlier introduced in October 2022 now affected a greater number of text encodings, including UTF-8.
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This makes sense to me. |
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@nielsdos Absolutely it is. This change was intended to target PHP-8.3, but I didn't enter the base branch correctly when opening the PR. |
| /* Alex messed up when reimplementing mb_substr and, in cases where `from` is non-zero and | ||
| * the number of characters to extract is more than 128, miscalculated where to end the substring | ||
| * Thanks to Maurício Fauth for finding the issue */ | ||
| var_dump(mb_substr('Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum dapibus feugiat ex non cursus. Pellentesque vestibulum tellus sit lectus.', 19, -1)); |
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Why not make this a separate test file altogether?
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@kamil-tekiela Thanks for the suggestion. Personally I prefer to have this particular test here rather than multiplying the number of different test files, but certainly some might prefer to have each test case in a different file. In any case, I do appreciate your bringing out this suggestion.
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Makes sense to me. |
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Thanks very much, all! The next releases of PHP 8.3 and 8.4 will include this fix. |
Fixes #12972.
Thanks to @MauricioFauth for finding and reporting this bug.
The bug was introduced in October 2022. It originally only affected text encodings which do not have a fixed byte width per characters and for which mbstring does not have an mblen_table. However, I recently made another change to mbstring, such that mb_substr no longer relies on the mblen_table even if one is available. Because of this change, the bug earlier introduced in October 2022 now affected a greater number of text encodings, including UTF-8.
@Girgias @cmb69 @youkidearitai @nielsdos @kamil-tekiela