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Improve parsing of import suggestions extending multiple multiline imports (fixes #4175) #4177

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Merged
merged 2 commits into from
Apr 15, 2024
Merged

Improve parsing of import suggestions extending multiple multiline imports (fixes #4175) #4177

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752f7cf
Fix parsing of import suggestions extending multiple multiline imports
jhrcek Apr 15, 2024
d320e1c
Remove extraneous space
jhrcek Apr 15, 2024
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9 changes: 6 additions & 3 deletions plugins/hls-refactor-plugin/src/Development/IDE/Plugin/CodeAction.hs
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Original file line number Diff line number Diff line change
Expand Up @@ -1973,15 +1973,18 @@ regexSingleMatch msg regex = case matchRegexUnifySpaces msg regex of
_ -> Nothing

-- | Process a list of (module_name, filename:src_span) values
-- | Eg. [(Data.Map, app/ModuleB.hs:2:1-18), (Data.HashMap.Strict, app/ModuleB.hs:3:1-29)]
--
-- Eg. [(Data.Map, app/ModuleB.hs:2:1-18), (Data.HashMap.Strict, app/ModuleB.hs:3:1-29)]
regExImports :: T.Text -> Maybe [(T.Text, T.Text)]
regExImports msg
| Just mods' <- allMatchRegex msg "‘([^’]*)’"
, Just srcspans' <- allMatchRegex msg
-- This regex has to be able to deal both with single-line srcpans like "(/path/to/File.hs:2:1-18)"
-- as well as multi-line srcspans like "(/path/to/File.hs:(3,1)-(5,2))"
#if MIN_VERSION_ghc(9,7,0)
"\\(at ([^)]*)\\)"
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@jhrcek jhrcek Apr 15, 2024 •
edited
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The original regex didn't correctly deal with import lists spanning multiple lines.
Instead of extracting the whole of

"(/path/to/File.hs:(3,1)-(5,2))"

it would only extract

"(/path/to/File.hs:(3,1)"
                       ^ -only up to first `)`

which led to errors in src span parser described in #4175

"\\(at ([^:]+:[^ ]+)\\)"
#else
"\\(([^)]*)\\)"
"\\(([^:]+:[^ ]+)\\)"
Comment on lines +1985 to +1987
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Since this is almost the same, do you think it is a good idea to remove the CPP and use a regex with an optional group like:
"\\((at )?([^:]+:[^ ]+)\\)"

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@jhrcek jhrcek Apr 15, 2024 •
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Unfortunately this doesn't work, because it introduces a new capturing group in the regex, which changes the number of matches and because of that it fails the check on this line:

haskell-language-server/plugins/hls-refactor-plugin/src/Development/IDE/Plugin/CodeAction.hs

Line 1989 in 97aac54

, let result = if length mods == length srcspans then

I thought I could use non-capturing groups (by adding ?: insite the parens), but then I learned the regex library we're using only supports posix-compliant regex syntax, so this is not supported.
I also remember that java had a way of specifying the index of the capturing group whose match you want to retrieve, but this doesn't seem to be supporter by regex-tdfa.. actually it is supported, but I don't think using more complicated regex functionality (getting capturing group by index) outweighs the benefit of removing one CPP 🤔

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I'll wait for further suggestions if you have any and will merge it in the afternoon otherwise.

#endif
, mods <- [mod | [_,mod] <- mods']
, srcspans <- [srcspan | [_,srcspan] <- srcspans']
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24 changes: 24 additions & 0 deletions plugins/hls-refactor-plugin/test/Main.hs
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Original file line number Diff line number Diff line change
Expand Up @@ -1501,6 +1501,30 @@ extendImportTests = testGroup "extend import actions"
, "f :: Foo"
, "f = undefined"
])
, testSession "data constructor with two multiline import lists that can be extended with it" $ template
[]
("A.hs", T.unlines
[ "module A where"
, "import Prelude ("
, " )"
, "import Data.Maybe ("
, " )"
, "f = Nothing"
])
(Range (Position 5 5) (Position 5 6))
[ "Add Maybe(..) to the import list of Data.Maybe"
, "Add Maybe(..) to the import list of Prelude"
, "Add Maybe(Nothing) to the import list of Data.Maybe"
, "Add Maybe(Nothing) to the import list of Prelude"
]
(T.unlines
["module A where"
, "import Prelude ("
, " )"
, "import Data.Maybe (Maybe (..)"
, " )"
, "f = Nothing"
])
]
where
codeActionTitle CodeAction{_title=x} = x
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