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Make llvm::Error generated from replacement interfaces more specific.
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Summary:
The new error information contains the type of error (e.g. overlap or bad file path)
and the replacement(s) that is causing the error. This enables us to resolve some errors.
For example, for insertion at the same location conflict, we need to know the
existing replacement which conflicts with the new replacement in order to calculate
the new position to be insert before/after the existing replacement (for merging).

Reviewers: klimek, bkramer

Subscribers: djasper, cfe-commits

Differential Revision: https://reviews.llvm.org/D26853

llvm-svn: 287639
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Eric Liu committed Nov 22, 2016
1 parent d70c03a commit e86a5f4
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Showing 3 changed files with 166 additions and 39 deletions.
56 changes: 56 additions & 0 deletions clang/include/clang/Tooling/Core/Replacement.h
View file
Expand Up @@ -22,11 +22,14 @@
#include "clang/Basic/FileManager.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/SourceLocation.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/raw_ostream.h"
#include <map>
#include <set>
#include <string>
#include <system_error>
#include <vector>

namespace clang {
Expand Down Expand Up @@ -137,6 +140,59 @@ class Replacement {
std::string ReplacementText;
};

enum class replacement_error {
fail_to_apply = 0,
wrong_file_path,
overlap_conflict,
insert_conflict,
};

/// \brief Carries extra error information in replacement-related llvm::Error,
/// e.g. fail applying replacements and replacements conflict.
class ReplacementError : public llvm::ErrorInfo<ReplacementError> {
public:
ReplacementError(replacement_error Err) : Err(Err) {}

/// \brief Constructs an error related to an existing replacement.
ReplacementError(replacement_error Err, Replacement Existing)
: Err(Err), ExistingReplacement(std::move(Existing)) {}

/// \brief Constructs an error related to a new replacement and an existing
/// replacement in a set of replacements.
ReplacementError(replacement_error Err, Replacement New, Replacement Existing)
: Err(Err), NewReplacement(std::move(New)),
ExistingReplacement(std::move(Existing)) {}

std::string message() const override;

void log(raw_ostream &OS) const override { OS << message(); }

replacement_error get() const { return Err; }

static char ID;

const llvm::Optional<Replacement> &getNewReplacement() const {
return NewReplacement;
}

const llvm::Optional<Replacement> &getExistingReplacement() const {
return ExistingReplacement;
}

private:
// Users are not expected to use error_code.
std::error_code convertToErrorCode() const override {
return llvm::inconvertibleErrorCode();
}

replacement_error Err;
// A new replacement, which is to expected be added into a set of
// replacements, that is causing problem.
llvm::Optional<Replacement> NewReplacement;
// An existing replacement in a replacements set that is causing problem.
llvm::Optional<Replacement> ExistingReplacement;
};

/// \brief Less-than operator between two Replacements.
bool operator<(const Replacement &LHS, const Replacement &RHS);

Expand Down
55 changes: 35 additions & 20 deletions clang/lib/Tooling/Core/Replacement.cpp
View file
Expand Up @@ -30,8 +30,7 @@ namespace tooling {

static const char * const InvalidLocation = "";

Replacement::Replacement()
: FilePath(InvalidLocation) {}
Replacement::Replacement() : FilePath(InvalidLocation) {}

Replacement::Replacement(StringRef FilePath, unsigned Offset, unsigned Length,
StringRef ReplacementText)
Expand Down Expand Up @@ -144,14 +143,33 @@ Replacements::getReplacementInChangedCode(const Replacement &R) const {
R.getReplacementText());
}

static llvm::Error makeConflictReplacementsError(const Replacement &New,
const Replacement &Existing) {
return llvm::make_error<llvm::StringError>(
"New replacement:\n" + New.toString() +
"\nconflicts with existing replacement:\n" + Existing.toString(),
llvm::inconvertibleErrorCode());
static std::string getReplacementErrString(replacement_error Err) {
switch (Err) {
case replacement_error::fail_to_apply:
return "Failed to apply a replacement.";
case replacement_error::wrong_file_path:
return "The new replacement's file path is different from the file path of "
"existing replacements";
case replacement_error::overlap_conflict:
return "The new replacement overlaps with an existing replacement.";
case replacement_error::insert_conflict:
return "The new insertion has the same insert location as an existing "
"replacement.";
}
llvm_unreachable("A value of replacement_error has no message.");
}

std::string ReplacementError::message() const {
std::string Message = getReplacementErrString(Err);
if (NewReplacement.hasValue())
Message += "\nNew replacement: " + NewReplacement->toString();
if (ExistingReplacement.hasValue())
Message += "\nExisting replacement: " + ExistingReplacement->toString();
return Message;
}

char ReplacementError::ID = 0;

Replacements Replacements::getCanonicalReplacements() const {
std::vector<Replacement> NewReplaces;
// Merge adjacent replacements.
Expand Down Expand Up @@ -202,17 +220,15 @@ Replacements::mergeIfOrderIndependent(const Replacement &R) const {
if (MergeShiftedRs.getCanonicalReplacements() ==
MergeShiftedReplaces.getCanonicalReplacements())
return MergeShiftedRs;
return makeConflictReplacementsError(R, *Replaces.begin());
return llvm::make_error<ReplacementError>(replacement_error::overlap_conflict,
R, *Replaces.begin());
}

llvm::Error Replacements::add(const Replacement &R) {
// Check the file path.
if (!Replaces.empty() && R.getFilePath() != Replaces.begin()->getFilePath())
return llvm::make_error<llvm::StringError>(
"All replacements must have the same file path. New replacement: " +
R.getFilePath() + ", existing replacements: " +
Replaces.begin()->getFilePath() + "\n",
llvm::inconvertibleErrorCode());
return llvm::make_error<ReplacementError>(
replacement_error::wrong_file_path, R, *Replaces.begin());

// Special-case header insertions.
if (R.getOffset() == UINT_MAX) {
Expand All @@ -239,9 +255,9 @@ llvm::Error Replacements::add(const Replacement &R) {
// Check if two insertions are order-indepedent: if inserting them in
// either order produces the same text, they are order-independent.
if ((R.getReplacementText() + I->getReplacementText()).str() !=
(I->getReplacementText() + R.getReplacementText()).str()) {
return makeConflictReplacementsError(R, *I);
}
(I->getReplacementText() + R.getReplacementText()).str())
return llvm::make_error<ReplacementError>(
replacement_error::insert_conflict, R, *I);
// If insertions are order-independent, we can merge them.
Replacement NewR(
R.getFilePath(), R.getOffset(), 0,
Expand Down Expand Up @@ -555,9 +571,8 @@ llvm::Expected<std::string> applyAllReplacements(StringRef Code,
Replacement Replace("<stdin>", I->getOffset(), I->getLength(),
I->getReplacementText());
if (!Replace.apply(Rewrite))
return llvm::make_error<llvm::StringError>(
"Failed to apply replacement: " + Replace.toString(),
llvm::inconvertibleErrorCode());
return llvm::make_error<ReplacementError>(
replacement_error::fail_to_apply, Replace);
}
std::string Result;
llvm::raw_string_ostream OS(Result);
Expand Down
94 changes: 75 additions & 19 deletions clang/unittests/Tooling/RefactoringTest.cpp
View file
Expand Up @@ -100,21 +100,71 @@ TEST_F(ReplacementTest, ReturnsInvalidPath) {
EXPECT_TRUE(Replace2.getFilePath().empty());
}

// Checks that an llvm::Error instance contains a ReplacementError with expected
// error code, expected new replacement, and expected existing replacement.
static bool checkReplacementError(
llvm::Error&& Error, replacement_error ExpectedErr,
llvm::Optional<Replacement> ExpectedExisting,
llvm::Optional<Replacement> ExpectedNew) {
if (!Error) {
llvm::errs() << "Error is a success.";
return false;
}
std::string ErrorMessage;
llvm::raw_string_ostream OS(ErrorMessage);
llvm::handleAllErrors(std::move(Error), [&](const ReplacementError &RE) {
llvm::errs() << "Handling error...\n";
if (ExpectedErr != RE.get())
OS << "Unexpected error code: " << int(RE.get()) << "\n";
if (ExpectedExisting != RE.getExistingReplacement()) {
OS << "Expected Existing != Actual Existing.\n";
if (ExpectedExisting.hasValue())
OS << "Expected existing replacement: " << ExpectedExisting->toString()
<< "\n";
if (RE.getExistingReplacement().hasValue())
OS << "Actual existing replacement: "
<< RE.getExistingReplacement()->toString() << "\n";
}
if (ExpectedNew != RE.getNewReplacement()) {
OS << "Expected New != Actual New.\n";
if (ExpectedNew.hasValue())
OS << "Expected new replacement: " << ExpectedNew->toString() << "\n";
if (RE.getNewReplacement().hasValue())
OS << "Actual new replacement: " << RE.getNewReplacement()->toString()
<< "\n";
}
});
OS.flush();
if (ErrorMessage.empty()) return true;
llvm::errs() << ErrorMessage;
return false;
}

TEST_F(ReplacementTest, FailAddReplacements) {
Replacements Replaces;
Replacement Deletion("x.cc", 0, 10, "3");
auto Err = Replaces.add(Deletion);
EXPECT_TRUE(!Err);
llvm::consumeError(std::move(Err));
Err = Replaces.add(Replacement("x.cc", 0, 2, "a"));
EXPECT_TRUE((bool)Err);
llvm::consumeError(std::move(Err));
Err = Replaces.add(Replacement("x.cc", 2, 2, "a"));
EXPECT_TRUE((bool)Err);
llvm::consumeError(std::move(Err));
Err = Replaces.add(Replacement("y.cc", 20, 2, ""));
EXPECT_TRUE((bool)Err);
llvm::consumeError(std::move(Err));

Replacement OverlappingReplacement("x.cc", 0, 2, "a");
Err = Replaces.add(OverlappingReplacement);
EXPECT_TRUE(checkReplacementError(std::move(Err),
replacement_error::overlap_conflict,
Deletion, OverlappingReplacement));

Replacement ContainedReplacement("x.cc", 2, 2, "a");
Err = Replaces.add(Replacement(ContainedReplacement));
EXPECT_TRUE(checkReplacementError(std::move(Err),
replacement_error::overlap_conflict,
Deletion, ContainedReplacement));

Replacement WrongPathReplacement("y.cc", 20, 2, "");
Err = Replaces.add(WrongPathReplacement);
EXPECT_TRUE(checkReplacementError(std::move(Err),
replacement_error::wrong_file_path,
Deletion, WrongPathReplacement));

EXPECT_EQ(1u, Replaces.size());
EXPECT_EQ(Deletion, *Replaces.begin());
}
Expand Down Expand Up @@ -299,9 +349,11 @@ TEST_F(ReplacementTest, FailAddRegression) {

// Make sure we find the overlap with the first entry when inserting a
// replacement that ends exactly at the seam of the existing replacements.
Err = Replaces.add(Replacement("x.cc", 5, 5, "fail"));
EXPECT_TRUE((bool)Err);
llvm::consumeError(std::move(Err));
Replacement OverlappingReplacement("x.cc", 5, 5, "fail");
Err = Replaces.add(OverlappingReplacement);
EXPECT_TRUE(checkReplacementError(std::move(Err),
replacement_error::overlap_conflict,
*Replaces.begin(), OverlappingReplacement));

Err = Replaces.add(Replacement("x.cc", 10, 0, ""));
EXPECT_TRUE(!Err);
Expand Down Expand Up @@ -333,9 +385,11 @@ TEST_F(ReplacementTest, AddInsertAtOtherInsertWhenOderIndependent) {
auto Err = Replaces.add(Replacement("x.cc", 10, 0, "a"));
EXPECT_TRUE(!Err);
llvm::consumeError(std::move(Err));
Err = Replaces.add(Replacement("x.cc", 10, 0, "b"));
EXPECT_TRUE((bool)Err);
llvm::consumeError(std::move(Err));
Replacement ConflictInsertion("x.cc", 10, 0, "b");
Err = Replaces.add(ConflictInsertion);
EXPECT_TRUE(checkReplacementError(std::move(Err),
replacement_error::insert_conflict,
*Replaces.begin(), ConflictInsertion));

Replaces.clear();
Err = Replaces.add(Replacement("x.cc", 10, 0, "a"));
Expand Down Expand Up @@ -436,10 +490,12 @@ TEST_F(ReplacementTest, FailOrderDependentReplacements) {
auto Replaces = toReplacements({Replacement(
Context.Sources, Context.getLocation(ID, 2, 1), 5, "other")});

auto Err = Replaces.add(Replacement(
Context.Sources, Context.getLocation(ID, 2, 1), 5, "rehto"));
EXPECT_TRUE((bool)Err);
llvm::consumeError(std::move(Err));
Replacement ConflictReplacement(Context.Sources,
Context.getLocation(ID, 2, 1), 5, "rehto");
auto Err = Replaces.add(ConflictReplacement);
EXPECT_TRUE(checkReplacementError(std::move(Err),
replacement_error::overlap_conflict,
*Replaces.begin(), ConflictReplacement));

EXPECT_TRUE(applyAllReplacements(Replaces, Context.Rewrite));
EXPECT_EQ("line1\nother\nline3\nline4", Context.getRewrittenText(ID));
Expand Down

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