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Do not throw exception when imports are collapsed to wildcard import #140
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It is kind of difficult to describe why this exception is thrown and the fact that it took me an entire working day to fix it should speak for itself. But I will try nevertheless to give a description: The problem starts in the class `OrganizeImports.AlwaysUseWildcards`. If the "collapse to wildcard import" option is enabled, this class replaces all imports that are matched by a wildcard import with such a wildcard import. Even though the wildcard import is generated it has positions since the position of the first matching import are set to it. This means that `ReusingPrinter` is used to print the import. However, in order to print import selectors the refactoring logic needs to generate its own trees, called `ImportSelectorTree`. This is necessary, since import selectors are not trees by default and therefore it wouldn't be easily possible to print them through the current tree printing algorithm. Since the `ImportSelectorTree` is synthetic, it doesn't have positions and is therefore forwarded to `PrettyPrinter`, therefore `PrettyPrinter` contains the bug fix. I didn't add the same logic to ReusingPrinter, since I don't see how such an implementation could ever be called there (there can't be a reusing part in a synthetic tree). Furthermore, the fix is more powerful, than what the test can cover. In theory it can even print rename imports but I was not able to come up with a test case that would invoke this logic, therefore we have no guarantee that this part of the implementation is correct or even necessary. Fixes #1002654
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Refer to this link for build results (access rights to CI server needed): https://jenkins.scala-ide.org:8496/jenkins/job/ghprb-scala-refactoring-validator/228/ |
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This looks like a perfectly fine solution for the problem! |
misto
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Feb 29, 2016
Do not throw exception when imports are collapsed to wildcard import
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It is kind of difficult to describe why this exception is thrown and the
fact that it took me an entire working day to fix it should speak for
itself. But I will try nevertheless to give a description:
The problem starts in the class
OrganizeImports.AlwaysUseWildcards. Ifthe "collapse to wildcard import" option is enabled, this class replaces
all imports that are matched by a wildcard import with such a wildcard
import. Even though the wildcard import is generated it has positions
since the position of the first matching import are set to it. This
means that
ReusingPrinteris used to print the import. However, inorder to print import selectors the refactoring logic needs to generate
its own trees, called
ImportSelectorTree. This is necessary, sinceimport selectors are not trees by default and therefore it wouldn't be
easily possible to print them through the current tree printing
algorithm. Since the
ImportSelectorTreeis synthetic, it doesn't havepositions and is therefore forwarded to
PrettyPrinter, thereforePrettyPrintercontains the bug fix.I didn't add the same logic to ReusingPrinter, since I don't see how
such an implementation could ever be called there (there can't be a
reusing part in a synthetic tree). Furthermore, the fix is more
powerful, than what the test can cover. In theory it can even print
rename imports but I was not able to come up with a test case that would
invoke this logic, therefore we have no guarantee that this part of the
implementation is correct or even necessary.
Fixes #1002654