As far as I understand, there were more changes in the appengine packages than just the import path.
Did you check if it works fine on appengine with the new import or does it require further changes? (I just want it confirmed, I assume that what's the test output is for)

I don't use cloudsql or appengine however it builds and runs outside of appengine and cloudsql without any problems. I just needed it to build so I could use it in my own app. Here is a rerun of go test github.com\rrbrussell\mysql -v

PS C:\Users\Robert\go\src\github.com\rrbrussell\mysql> go test github.com\rrbrussell\mysql -v
=== RUN   TestInterpolateParams
--- PASS: TestInterpolateParams (0.00s)
=== RUN   TestInterpolateParamsTooManyPlaceholders
--- PASS: TestInterpolateParamsTooManyPlaceholders (0.00s)
=== RUN   TestInterpolateParamsPlaceholderInString
--- PASS: TestInterpolateParamsPlaceholderInString (0.00s)
=== RUN   TestMultiResultSet
--- PASS: TestMultiResultSet (0.02s)
=== RUN   TestMultiResultSetNoSelect
--- PASS: TestMultiResultSetNoSelect (0.00s)
=== RUN   TestSkipResults
--- PASS: TestSkipResults (0.01s)
=== RUN   TestPingContext
--- PASS: TestPingContext (0.01s)
=== RUN   TestContextCancelExec
[mysql] 2017/11/17 05:12:23 connection.go:372: invalid connection
[mysql] 2017/11/17 05:12:24 connection.go:372: invalid connection
[mysql] 2017/11/17 05:12:25 connection.go:372: invalid connection
--- PASS: TestContextCancelExec (3.51s)
=== RUN   TestContextCancelQuery
[mysql] 2017/11/17 05:12:26 connection.go:372: invalid connection
[mysql] 2017/11/17 05:12:27 connection.go:372: invalid connection
[mysql] 2017/11/17 05:12:29 connection.go:372: invalid connection
--- PASS: TestContextCancelQuery (3.53s)
=== RUN   TestContextCancelQueryRow
[mysql] 2017/11/17 05:12:29 connection.go:311: invalid connection
[mysql] 2017/11/17 05:12:29 connection.go:311: invalid connection
--- PASS: TestContextCancelQueryRow (0.56s)
=== RUN   TestContextCancelPrepare
--- PASS: TestContextCancelPrepare (0.01s)
=== RUN   TestContextCancelStmtExec
[mysql] 2017/11/17 05:12:30 connection.go:372: invalid connection
[mysql] 2017/11/17 05:12:32 connection.go:372: invalid connection
[mysql] 2017/11/17 05:12:33 connection.go:372: invalid connection
--- PASS: TestContextCancelStmtExec (3.54s)
=== RUN   TestContextCancelStmtQuery
[mysql] 2017/11/17 05:12:34 connection.go:372: invalid connection
[mysql] 2017/11/17 05:12:35 connection.go:372: invalid connection
[mysql] 2017/11/17 05:12:36 connection.go:372: invalid connection
--- PASS: TestContextCancelStmtQuery (3.50s)
=== RUN   TestContextCancelBegin
--- PASS: TestContextCancelBegin (3.27s)
=== RUN   TestContextBeginIsolationLevel
--- PASS: TestContextBeginIsolationLevel (0.19s)
=== RUN   TestContextBeginReadOnly
--- PASS: TestContextBeginReadOnly (0.17s)
=== RUN   TestRowsColumnTypes
--- PASS: TestRowsColumnTypes (0.41s)
=== RUN   TestEmptyQuery
--- PASS: TestEmptyQuery (0.01s)
=== RUN   TestCRUD
--- PASS: TestCRUD (0.20s)
=== RUN   TestMultiQuery
--- PASS: TestMultiQuery (0.06s)
=== RUN   TestInt
--- PASS: TestInt (1.73s)
=== RUN   TestFloat32
--- PASS: TestFloat32 (0.35s)
=== RUN   TestFloat64
--- PASS: TestFloat64 (0.44s)
=== RUN   TestFloat64Placeholder
--- PASS: TestFloat64Placeholder (0.32s)
=== RUN   TestString
--- PASS: TestString (1.49s)
=== RUN   TestDateTime
--- PASS: TestDateTime (0.03s)
=== RUN   TestTimestampMicros
--- PASS: TestTimestampMicros (0.01s)
=== RUN   TestNULL
--- PASS: TestNULL (0.19s)
=== RUN   TestUint64
--- PASS: TestUint64 (0.01s)
=== RUN   TestLongData
--- PASS: TestLongData (3.95s)
=== RUN   TestLoadData
--- PASS: TestLoadData (0.30s)
=== RUN   TestFoundRows
--- PASS: TestFoundRows (0.38s)
=== RUN   TestTLS
--- SKIP: TestTLS (0.00s)
        driver_test.go:1183: server does not support TLS
=== RUN   TestReuseClosedConnection
[mysql] 2017/11/17 05:12:50 statement.go:49: invalid connection
--- PASS: TestReuseClosedConnection (0.00s)
=== RUN   TestCharset
--- PASS: TestCharset (0.02s)
=== RUN   TestFailingCharset
--- PASS: TestFailingCharset (0.01s)
=== RUN   TestCollation
--- PASS: TestCollation (0.04s)
=== RUN   TestColumnsWithAlias
--- PASS: TestColumnsWithAlias (0.01s)
=== RUN   TestRawBytesResultExceedsBuffer
--- PASS: TestRawBytesResultExceedsBuffer (0.01s)
=== RUN   TestTimezoneConversion
--- PASS: TestTimezoneConversion (0.69s)
=== RUN   TestRowsClose
--- PASS: TestRowsClose (0.01s)
=== RUN   TestCloseStmtBeforeRows
--- PASS: TestCloseStmtBeforeRows (0.01s)
=== RUN   TestStmtMultiRows
--- PASS: TestStmtMultiRows (0.01s)
=== RUN   TestPreparedManyCols
--- PASS: TestPreparedManyCols (0.04s)
=== RUN   TestConcurrent
--- SKIP: TestConcurrent (0.00s)
        driver_test.go:1617: MYSQL_TEST_CONCURRENT env var not set
=== RUN   TestCustomDial
--- PASS: TestCustomDial (0.00s)
=== RUN   TestSQLInjection
--- PASS: TestSQLInjection (0.67s)
=== RUN   TestInsertRetrieveEscapedData
--- PASS: TestInsertRetrieveEscapedData (0.30s)
=== RUN   TestUnixSocketAuthFail
--- PASS: TestUnixSocketAuthFail (0.01s)
        driver_test.go:1791: socket: MySQL
        driver_test.go:1791: socket: MySQL
        driver_test.go:1791: socket: MySQL
=== RUN   TestInterruptBySignal
--- PASS: TestInterruptBySignal (0.01s)
=== RUN   TestColumnsReusesSlice
--- PASS: TestColumnsReusesSlice (0.00s)
=== RUN   TestRejectReadOnly
--- PASS: TestRejectReadOnly (0.31s)
=== RUN   TestPing
--- PASS: TestPing (0.01s)
=== RUN   TestDSNParser
--- PASS: TestDSNParser (0.00s)
=== RUN   TestDSNParserInvalid
--- PASS: TestDSNParserInvalid (0.00s)
=== RUN   TestDSNReformat
--- PASS: TestDSNReformat (0.00s)
=== RUN   TestDSNWithCustomTLS
--- PASS: TestDSNWithCustomTLS (0.00s)
=== RUN   TestDSNWithCustomTLSQueryEscape
--- PASS: TestDSNWithCustomTLSQueryEscape (0.00s)
=== RUN   TestDSNUnsafeCollation
--- PASS: TestDSNUnsafeCollation (0.00s)
=== RUN   TestParamsAreSorted
--- PASS: TestParamsAreSorted (0.00s)
=== RUN   TestErrorsSetLogger
--- PASS: TestErrorsSetLogger (0.00s)
=== RUN   TestErrorsStrictIgnoreNotes
--- PASS: TestErrorsStrictIgnoreNotes (0.01s)
=== RUN   TestReadPacketSingleByte
--- PASS: TestReadPacketSingleByte (0.00s)
=== RUN   TestReadPacketWrongSequenceID
--- PASS: TestReadPacketWrongSequenceID (0.00s)
=== RUN   TestReadPacketSplit
--- PASS: TestReadPacketSplit (0.13s)
=== RUN   TestReadPacketFail
[mysql] 2017/11/17 05:12:52 packets.go:58: malformed packet
[mysql] 2017/11/17 05:12:52 packets.go:36: connection is closed
[mysql] 2017/11/17 05:12:52 packets.go:36: too many reads
--- PASS: TestReadPacketFail (0.00s)
=== RUN   TestIsolationLevelMapping
--- PASS: TestIsolationLevelMapping (0.00s)
=== RUN   TestScanNullTime
--- PASS: TestScanNullTime (0.00s)
=== RUN   TestLengthEncodedInteger
--- PASS: TestLengthEncodedInteger (0.00s)
=== RUN   TestOldPass
--- PASS: TestOldPass (0.00s)
=== RUN   TestFormatBinaryDateTime
--- PASS: TestFormatBinaryDateTime (0.00s)
=== RUN   TestEscapeBackslash
--- PASS: TestEscapeBackslash (0.00s)
=== RUN   TestEscapeQuotes
--- PASS: TestEscapeQuotes (0.00s)
=== RUN   TestAtomicBool
--- PASS: TestAtomicBool (0.00s)
=== RUN   TestAtomicError
--- PASS: TestAtomicError (0.00s)
PASS
ok      github.com/rrbrussell/mysql     30.677s
PS C:\Users\Robert\go\src\github.com\rrbrussell\mysql>

Okay, I'm going to merge this then. Please immediately report back if this breaks something.

it builds and runs outside of appengine and cloudsql without any problems. I just needed it to build so I could use it in my own app.

Just a question: there is build tag (// +build appengine) in appengine.go. So it is not compiled
outside of appengine. That's why many Go users use this project without any problem.
Why this fix is needed for your own app?

I am not as familiar with the golang tool chain as I am with some of the other programming language tool chains I use.

I am not sure which tool was throwing the error message out. The Issue was occurring during dependency vendoring. The build tag may not be checked due to a bug in govedor or in one of the other tools that supports vendoring dependencies.

This LGTM. There were no changes to the cloudsql package with the import path change.