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Improve diagnostics to explain why an identifier isn't a valid #893

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Improve diagnostics to explain why an identifier isn't a valid #893

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17 changes: 13 additions & 4 deletions Sources/SwiftDriver/Driver/Driver.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -2137,10 +2137,19 @@ extension Driver {
moduleName = "__bad__"
}
}

if !moduleName.sd_isSwiftIdentifier {
fallbackOrDiagnose(.error_bad_module_name(moduleName: moduleName, explicitModuleName: parsedOptions.contains(.moduleName)))
} else if moduleName == "Swift" && !parsedOptions.contains(.parseStdlib) {

do {
try moduleName.sd_validateSwiftIdentifier()
}
catch let validationFailure as InvalidSwiftIdentifierError {
fallbackOrDiagnose(.error_bad_module_name(
moduleName: moduleName,
explicitModuleName: parsedOptions.contains(.moduleName),
validationFailureReason: validationFailure.reason
))
}

if moduleName == "Swift" && !parsedOptions.contains(.parseStdlib) {
fallbackOrDiagnose(.error_stdlib_module_name(moduleName: moduleName, explicitModuleName: parsedOptions.contains(.moduleName)))
}

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7 changes: 4 additions & 3 deletions Sources/SwiftDriver/Utilities/Diagnostics.swift
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Expand Up @@ -63,16 +63,17 @@ extension Diagnostic.Message {

static func error_bad_module_name(
moduleName: String,
explicitModuleName: Bool
explicitModuleName: Bool,
validationFailureReason reason: String
) -> Diagnostic.Message {
let suffix: String
if explicitModuleName {
suffix = ""
} else {
suffix = "; use -module-name flag to specify an alternate name"
suffix = " Use -module-name flag to specify an alternate name"
}

return .error("module name \"\(moduleName)\" is not a valid identifier\(suffix)")
return .error("module name \"\(moduleName)\" is not a valid Swift identifier, because \(reason).\(suffix)")
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The existing style of having separate clauses is intentional as it matches clang.

}

static func error_stdlib_module_name(
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23 changes: 15 additions & 8 deletions Sources/SwiftDriver/Utilities/StringAdditions.swift
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Expand Up @@ -9,17 +9,24 @@
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//

public struct InvalidSwiftIdentifierError: Error {
let reason: String
}

extension String {
/// Whether this string is a Swift identifier.
public var sd_isSwiftIdentifier: Bool {
guard let start = unicodeScalars.first else {
return false
}

let continuation = unicodeScalars.dropFirst()

return start.isValidSwiftIdentifierStart &&
continuation.allSatisfy { $0.isValidSwiftIdentifierContinuation }
do {
try sd_validateSwiftIdentifier()
return true
} catch {
return false
}
}

public func sd_validateSwiftIdentifier() throws {
// TODO: implement me
}
}

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81 changes: 62 additions & 19 deletions Tests/SwiftDriverTests/StringAdditionsTests.swift
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Expand Up @@ -12,6 +12,7 @@

import XCTest
import SwiftDriver
import TSCTestSupport

final class StringAdditionsTests: XCTestCase {

Expand All @@ -20,25 +21,52 @@ final class StringAdditionsTests: XCTestCase {
XCTAssertTrue("_startsWithUnderscore".sd_isSwiftIdentifier)
XCTAssertTrue("contains_Number5".sd_isSwiftIdentifier)
XCTAssertTrue("_1".sd_isSwiftIdentifier)
XCTAssertFalse("5startsWithNumber".sd_isSwiftIdentifier)
XCTAssertFalse("contains space".sd_isSwiftIdentifier)
XCTAssertFalse("contains\nnewline".sd_isSwiftIdentifier)
XCTAssertFalse("contains\ttab".sd_isSwiftIdentifier)
XCTAssertFalse("contains_punctuation,.!?#".sd_isSwiftIdentifier)
XCTAssertTrue("contains$dollar".sd_isSwiftIdentifier)
XCTAssertFalse("$startsWithDollar".sd_isSwiftIdentifier)
XCTAssertFalse("operators+-=*/^".sd_isSwiftIdentifier)
XCTAssertFalse("braces{}".sd_isSwiftIdentifier)
XCTAssertFalse("angleBrackets<>".sd_isSwiftIdentifier)
XCTAssertFalse("parens()".sd_isSwiftIdentifier)
XCTAssertFalse("squareBrackets[]".sd_isSwiftIdentifier)

XCTAssertFalse("<#some name#>".sd_isSwiftIdentifier,
"Placeholders are not valid identifiers")

XCTAssertFalse("".sd_isSwiftIdentifier)
XCTAssertFalse("`$`".sd_isSwiftIdentifier)
XCTAssertFalse("backtick`".sd_isSwiftIdentifier)

assertInvalidIdentifier("5startsWithNumber", expectedMessage:
"Swift identifiers cannot start with a number")

assertInvalidIdentifier("contains space", expectedMessage:
"Swift identifiers cannot contains spaces")

assertInvalidIdentifier("contains\nnewline", expectedMessage:
"Swift identifiers cannot contain new line characters")

assertInvalidIdentifier("contains\ttab", expectedMessage:
"Swift identifiers cannot contain tab characters")

assertInvalidIdentifier("contains_punctuation,.!?#", expectedMessage:
##"Swift identifiers cannot contain punctuation (like ",", ".", "!", "?", or "#")"##)

assertInvalidIdentifier("$startsWithDollar", expectedMessage:
#"Swift identifiers cannot start with a dollar sign ("$")"#)

assertInvalidIdentifier("operators+-=*/^", expectedMessage:
#"Swift identifiers cannot contain operators (like "+", "-", "=", "*", "/", or "^")"#)

assertInvalidIdentifier("braces{}", expectedMessage:
#"Swift identifiers cannot contain curly braces ("{" or "}")"#)

assertInvalidIdentifier("angleBrackets<>", expectedMessage:
#"Swift identifiers cannot contain parenthesis ("<" or ">")"#)

assertInvalidIdentifier("parens()", expectedMessage:
#"Swift identifiers cannot contain parenthesis ("(" or ")")"#)

assertInvalidIdentifier("squareBrackets[]", expectedMessage:
#"Swift identifiers cannot contain square brackets ("[" or "]")"#)

assertInvalidIdentifier("<#some name#>", expectedMessage:
"Swift identifiers cannot contain Xcode placeholders")

assertInvalidIdentifier("", expectedMessage:
"Swift identifiers cannot be empty")

assertInvalidIdentifier("`$`", expectedMessage:
"Swift identifiers cannot be only a dollar sign") // TODO: what's the exact rule here?

assertInvalidIdentifier("backtick`", expectedMessage:
"Swift identifiers cannot contain mis-matched backticks") // TODO: what's the exact rule here?
}

func testSwiftKeywordsAsIdentifiers() {
Expand All @@ -58,7 +86,7 @@ final class StringAdditionsTests: XCTestCase {

func testUnicodeCharacters() {
XCTAssertTrue("👨".sd_isSwiftIdentifier)
XCTAssertFalse("❤️".sd_isSwiftIdentifier)
XCTAssertFalse("❤️".sd_isSwiftIdentifier) // Multiple codepoints
XCTAssertTrue("💑".sd_isSwiftIdentifier) // Single codepoint
XCTAssertFalse("🙍🏻‍♂️".sd_isSwiftIdentifier) // Multiple codepoints
XCTAssertTrue("你好".sd_isSwiftIdentifier)
Expand All @@ -76,4 +104,19 @@ final class StringAdditionsTests: XCTestCase {
XCTAssertFalse("".sd_isSwiftIdentifier,
"Private-use characters aren't valid Swift identifiers")
}

private func assertInvalidIdentifier(
_ invalidIdentifier: String,
expectedMessage: String,
file: StaticString = #file,
line: UInt = #line
) {
XCTAssertThrows(try invalidIdentifier.sd_validateSwiftIdentifier()) { e in
guard let e = e as? InvalidSwiftIdentifierError else {
XCTFail()
return
}
XCTAssertEqual(e.message, expectedMesssage)
}
}
}