Compile error found in "samples/snippets"

[HailongWen]

I followed the Getting started with Cloud Spanner in Java and did the following:

$ git clone https://github.com/googleapis/java-spanner.git
$ cd java-spanner/samples/snippets
$ mvn package

However, the compilation failed. Note that I did the same thing a while ago and it did work. So I guess this is caused by recent releases that include incompatible changes?

FYI, the errors are:

[INFO] -------------------------------------------------------------
[WARNING] COMPILATION WARNING : 
[INFO] -------------------------------------------------------------
[WARNING] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/TracingSample.java: /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/TracingSample.java uses or overrides a deprecated API.
[WARNING] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/TracingSample.java: Recompile with -Xlint:deprecation for details.
[INFO] 2 warnings 
[INFO] -------------------------------------------------------------
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR : 
[INFO] -------------------------------------------------------------
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/CreateBackupWithEncryptionKey.java:[30,43] package com.google.cloud.spanner.encryption does not exist
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/RestoreBackupWithEncryptionKey.java:[26,32] cannot find symbol
  symbol:   class Restore
  location: package com.google.cloud.spanner
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/RestoreBackupWithEncryptionKey.java:[30,43] package com.google.cloud.spanner.encryption does not exist
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/CreateDatabaseWithEncryptionKey.java:[28,43] package com.google.cloud.spanner.encryption does not exist
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/CreateBackupWithEncryptionKey.java:[72,30] cannot find symbol
  symbol:   variable EncryptionConfigs
  location: class com.example.spanner.CreateBackupWithEncryptionKey
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/RestoreBackupWithEncryptionKey.java:[62,11] cannot find symbol
  symbol:   class Restore
  location: class com.example.spanner.RestoreBackupWithEncryptionKey
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/RestoreBackupWithEncryptionKey.java:[63,9] cannot find symbol
  symbol:   method newRestoreBuilder(com.google.cloud.spanner.BackupId,com.google.cloud.spanner.DatabaseId)
  location: variable adminClient of type com.google.cloud.spanner.DatabaseAdminClient
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/RestoreBackupWithEncryptionKey.java:[66,30] cannot find symbol
  symbol:   variable EncryptionConfigs
  location: class com.example.spanner.RestoreBackupWithEncryptionKey
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/RestoreBackupWithEncryptionKey.java:[92,17] cannot find symbol
  symbol:   method getEncryptionConfig()
  location: variable database of type com.google.cloud.spanner.Database
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/CreateDatabaseWithEncryptionKey.java:[60,9] cannot find symbol
  symbol:   method newDatabaseBuilder(com.google.cloud.spanner.DatabaseId)
  location: variable adminClient of type com.google.cloud.spanner.DatabaseAdminClient
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/CreateDatabaseWithEncryptionKey.java:[61,30] cannot find symbol
  symbol:   variable EncryptionConfigs
  location: class com.example.spanner.CreateDatabaseWithEncryptionKey
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/CreateDatabaseWithEncryptionKey.java:[64,9] method createDatabase in interface com.google.cloud.spanner.DatabaseAdminClient cannot be applied to given types;
  required: java.lang.String,java.lang.String,java.lang.Iterable<java.lang.String>
  found:    com.google.cloud.spanner.Database,java.util.List<java.lang.String>
  reason: actual and formal argument lists differ in length
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/CreateDatabaseWithEncryptionKey.java:[85,26] cannot find symbol
  symbol:   method getEncryptionConfig()
  location: variable createdDatabase of type com.google.cloud.spanner.Database
[INFO] 13 errors 
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 4.263 s
[INFO] Finished at: 2021-04-07T11:46:56-07:00
[INFO] Final Memory: 38M/224M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project spanner-snippets: Compilation failure: Compilation failure: 
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/CreateBackupWithEncryptionKey.java:[30,43] package com.google.cloud.spanner.encryption does not exist
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/RestoreBackupWithEncryptionKey.java:[26,32] cannot find symbol
[ERROR]   symbol:   class Restore
[ERROR]   location: package com.google.cloud.spanner
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/RestoreBackupWithEncryptionKey.java:[30,43] package com.google.cloud.spanner.encryption does not exist
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/CreateDatabaseWithEncryptionKey.java:[28,43] package com.google.cloud.spanner.encryption does not exist
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/CreateBackupWithEncryptionKey.java:[72,30] cannot find symbol
[ERROR]   symbol:   variable EncryptionConfigs
[ERROR]   location: class com.example.spanner.CreateBackupWithEncryptionKey
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/RestoreBackupWithEncryptionKey.java:[62,11] cannot find symbol
[ERROR]   symbol:   class Restore
[ERROR]   location: class com.example.spanner.RestoreBackupWithEncryptionKey
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/RestoreBackupWithEncryptionKey.java:[63,9] cannot find symbol
[ERROR]   symbol:   method newRestoreBuilder(com.google.cloud.spanner.BackupId,com.google.cloud.spanner.DatabaseId)
[ERROR]   location: variable adminClient of type com.google.cloud.spanner.DatabaseAdminClient
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/RestoreBackupWithEncryptionKey.java:[66,30] cannot find symbol
[ERROR]   symbol:   variable EncryptionConfigs
[ERROR]   location: class com.example.spanner.RestoreBackupWithEncryptionKey
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/RestoreBackupWithEncryptionKey.java:[92,17] cannot find symbol
[ERROR]   symbol:   method getEncryptionConfig()
[ERROR]   location: variable database of type com.google.cloud.spanner.Database
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/CreateDatabaseWithEncryptionKey.java:[60,9] cannot find symbol
[ERROR]   symbol:   method newDatabaseBuilder(com.google.cloud.spanner.DatabaseId)
[ERROR]   location: variable adminClient of type com.google.cloud.spanner.DatabaseAdminClient
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/CreateDatabaseWithEncryptionKey.java:[61,30] cannot find symbol
[ERROR]   symbol:   variable EncryptionConfigs
[ERROR]   location: class com.example.spanner.CreateDatabaseWithEncryptionKey
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/CreateDatabaseWithEncryptionKey.java:[64,9] method createDatabase in interface com.google.cloud.spanner.DatabaseAdminClient cannot be applied to given types;
[ERROR]   required: java.lang.String,java.lang.String,java.lang.Iterable<java.lang.String>
[ERROR]   found:    com.google.cloud.spanner.Database,java.util.List<java.lang.String>
[ERROR]   reason: actual and formal argument lists differ in length
[ERROR] /tmp/java-spanner/samples/snippets/src/main/java/com/example/spanner/CreateDatabaseWithEncryptionKey.java:[85,26] cannot find symbol
[ERROR]   symbol:   method getEncryptionConfig()
[ERROR]   location: variable createdDatabase of type com.google.cloud.spanner.Database
[ERROR] -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException

[olavloite]

@skuruppu
The problem is that the samples/snippets project is using the Spanner client library version from the Google libraries bom. That is version 5.1.0. Encryption was added in version 6.x. As far as I can tell this was probably caused by the following:

1. The samples for Database and Backup encryption was merged a little while ago.
2. That PR probably used a manually set version locally during development, which meant that it wasn't noticed during development.
3. The CI environment currently does not execute any (integration) tests on the samples as these take too long. Instead, there are (as far as I know) tests executed only on nightly builds. I would expect those nightly builds currently also to be broken. The PR was therefore also green on CI.

I think the best thing to do here is to:

1. Revert samples: adds samples for CMEK #989 for now and add it back once Spanner client library 6.x is available in the BOM.
2. Change the build script to at least do a compile of the samples (but perhaps we should also add a couple of unit tests to the samples just to add an extra level of certainty).

[thiagotnunes]

The samples dependencies have been updated and should compile now in the latest release: #1046