On 8/24/18 9:24 AM, David Malcolm wrote: > This patch tunes class best_match's cutoff for rejecting meaningless > spelling suggestions. > > Previously, we allowed an edit distance of up to half of the length of the > longer of the goal string and closest candidate strings, rounded down. > > With this patch, we now allow only up to a third - with some tuning of > rounding (and for very short strings), to ensure that: > (a) everything that worked before still works (with the removal of a > couple of cases that shouldn't), and that > (b) the new threshold is always at least as conservative as the old > threshold and thus shouldn't offer new nonsensical suggestions (with > the possible exception of cases where transposition has helped; see > r261521 aka Damerau-Levenshtein; PR other/69968). > > In particular, all of the bogus suggestions from PR c/82967 are now > no longer offered. > > Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu; > adds 4 PASS results to gcc.sum. > > OK for trunk? > > OK for backporting to gcc 8? (with the caveat that gcc 8's > edit distance doesn't do transpositions) > > gcc/ChangeLog: > PR c/82967 > * spellcheck.c (get_edit_distance_cutoff): New function. > (selftest::test_edit_distance_unit_test_oneway): Rename to... > (selftest::test_get_edit_distance_one_way): ...this. > (selftest::test_get_edit_distance_unit): Rename to... > (selftest::test_get_edit_distance_both_ways): ...this. > (selftest::test_edit_distances): Move tests to this new function, > and test some more pairs of strings. Update for above renaming. > (selftest::get_old_cutoff): New function. > (selftest::test_get_edit_distance_cutoff): New function. > (selftest::assert_suggested_for): New function. > (ASSERT_SUGGESTED_FOR): New macro. > (selftest::assert_not_suggested_for): New function. > (ASSERT_NOT_SUGGESTED_FOR): New macro. > (selftest::test_suggestions): New function. > (selftest::spellcheck_c_tests): Move test_get_edit_distance_unit > tests to selftest::test_edit_distances and call it. Add calls to > selftest::test_get_edit_distance_cutoff and > selftest::test_suggestions. > * spellcheck.h (get_edit_distance_cutoff): New function declaration. > (best_match::consider): Replace hard-coded cutoff calculation with > a call to... > (best_match::get_cutoff): New declaration. > (best_match::get_best_meaningful_candidate): Likewise. > > gcc/testsuite/ChangeLog: > PR c/82967 > * c-c++-common/attributes-1.c: Remove bogus suggestion from > dg-prune-output. > * gcc.dg/diagnostic-token-ranges.c (undeclared_identifier): Remove > bogus suggestion. > * gcc.dg/spellcheck-identifiers-4.c: New test. ISTM that while not technically listed as a maintainer for this stuff, you're by far the most well versed in the implementation. Rubber-stamped with an OK.
jeff
