feat!: Upgrade Bigtable to V2

[saranshdhingra]

This PR takes care of the following:

• Upgrade the GAPIC surface to V2.
• Disables GAX retries in ResumableStream and only use the local retries in the class.
• Modifies the Table, ResumableStream and ChunkFormatter classes to deal with requests and not options(used in GAPIC v1 surface).
• Remove the old alias classes.
• Use the preferred GAX traits instead of the one's in Core.
• Use retrySettings.maxRetries instead of the old retries param.
• Write the migrating guide.
• Remove V1 GAPIC files, and V1 tests. Add the reference to the V2 GAPIC clients in the migration doc.
• Modify the use of EmulatorTrait
• Generate new surface LROs (see feat: use new surface LROs in new surface clients gapic-generator-php#714)
• Remove deprecated code from Bigtable/owlbot.py (see chore(Bigtable): generator changes from owlbot for V2 #7352)
• Migrate Bigtable to "New Surface Only" (see cl/638452649)
• Ensure all sample tests in php-docs-samples/bigtable pass (see chore: upgrade bigtable samples to v2 GoogleCloudPlatform/php-docs-samples#2012)

BREAKING_CHANGE_REASON=RC-1 for the version 2 of the Bigtable library.

[bshaffer]

For the --prefer-lowest, you need to update Bigtable's minimum google/cloud-core version to one that contains the DetectProjectIdTrait:

PHP Fatal error:  Trait "Google\Cloud\Core\DetectProjectIdTrait" not found in /home/runner/work/google-cloud-php/google-cloud-php/Bigtable/src/BigtableClient.php on line 43
.................Running Bigtable Snippet Tests
PHP Fatal error:  Trait "Google\Cloud\Core\ApiHelperTrait" not found in /home/runner/work/google-cloud-php/google-cloud-php/Bigtable/src/Table.php on line 53

[bshaffer]

For the failing tests:

See the GAPIC generator: the logic that adds the emulator environment variable is now handed by GAPIC
you don't need to call modifyClientOptions anymore, you just need to add the spanner client to the EmulatorSupportGenerator, and you can remove SpannerEmulatorTrait.

To fix the unit tests, just add the same logic to bypass finals to the bootstrap file in Core/unit-bootstrap.php, which is the bootstrap file used in the root phpunit.xml.dist

[saranshdhingra]

googleapis/gapic-generator-php#717 is needed for emulator tests to pass.

[bshaffer]

We need to take a look at Bigtable/owlbot.py because some very strange things are happening there. I am hoping that the following likes can be removed entirely:

google-cloud-php/Bigtable/owlbot.py

Lines 61 to 117 in 7e98d79

	# fix unit test namespace
	s.replace(
	'tests/Unit/Admin/*/*.php',
	r'namespace Google\\Cloud\\Bigtable\\Admin\\Tests\\Unit',
	r'namespace Google\\Cloud\\Bigtable\\Tests\\Unit\\Admin')
	# fix test group
	s.replace(
	'tests/**/Admin/**/*Test.php',
	'@group admin',
	'@group bigtable' + '\n' + ' * bigtable-admin')
	# Fix class references in gapic samples
	for version in ['V2']:
	pathExpr = [
	'src/' + version + '/Gapic/BigtableGapicClient.php',
	'src/Admin/' + version + '/Gapic/*GapicClient.php'
	]
	types = {
	'new BigtableClient': r'new Google\\Cloud\\Bigtable\\' + version + r'\\BigtableClient',
	'new BigtableInstanceAdminClient': r'new Google\\Cloud\\Bigtable\\Admin\\' + version + r'\\BigtableInstanceAdminClient',
	r'\$instance = new Instance': r'$instance = new Google\\Cloud\\Bigtable\\Admin\\' + version + r'\\Instance',
	'= Type::': r'= Google\\Cloud\\Bigtable\\Admin\\' + version + r'\\Instance\\Type::',
	'new FieldMask': r'new Google\\Protobuf\\FieldMask',
	r'\$cluster = new Cluster': r'$cluster = new Google\\Cloud\\Bigtable\\Admin\\' + version + r'\\Cluster',
	'new AppProfile': r'new Google\\Cloud\\Bigtable\\Admin\\' + version + r'\\AppProfile',
	'new Policy': r'new Google\\Cloud\\Iam\\V1\\Policy',
	'new BigtableTableAdminClient': r'new Google\\Cloud\\Bigtable\\Admin\\' + version + r'\\BigtableTableAdminClient',
	'new Table': r'new Google\\Cloud\\Bigtable\\Admin\\' + version + r'\\Table',
	}
	for search, replace in types.items():
	s.replace(
	pathExpr,
	search,
	replace
	)
	### [START] protoc backwards compatibility fixes
	# roll back to private properties.
	s.replace(
	"src/**/V*/**/*.php",
	r"Generated from protobuf field ([^\n]{0,})\n\s{5}\*/\n\s{4}protected \$",
	r"""Generated from protobuf field \1
	*/
	private $""")
	# Replace "Unwrapped" with "Value" for method names.
	s.replace(
	"src/**/V*/**/*.php",
	r"public function ([s|g]\w{3,})Unwrapped",
	r"public function \1Value"
	)
	### [END] protoc backwards compatibility fixes

Also, we'll want to make sure googleapis/gapic-generator-php#714 is merged and generated for the Admin client, as it contains LRO's (cc @noahdietz)

[ajupazhamayil]

Do we need to check if the OptionalConfiguration also passed correctly?

[bshaffer]

So it seems like we should change this to

Suggested change

	$this->bigtableClient->mutateRows(
	Argument::type(MutateRowsRequest::class),
	Argument::type('array')
	)->shouldBeCalled()
	$this->bigtableClient->mutateRows(
	Argument::type(MutateRowsRequest::class),
	$this->options + $options
	)->shouldBeCalled()

This will test that the custom options we expect will show up.

I see that you've changed it from key1 => value1 to transportOptions, to make sure they're valid call options. That works for me!

[bshaffer]

After running the tests in php-docs-samples/bigtable against this PR, I received the following exceptions:

Next Google\ApiCore\ValidationException: Error decoding message: cannot handle unknown field row_filter on message google.bigtable.v2.ReadRowsRequest in vendor/google/gax/src/Serializer.php:149
Stack trace:
#0 vendor/google/cloud/Bigtable/src/Table.php(332): Google\ApiCore\Serializer->decodeMessage(Object(Google\Cloud\Bigtable\V2\ReadRowsRequest), Array)
#1 vendor/google/cloud/Bigtable/src/Table.php(358): Google\Cloud\Bigtable\Table->readRows(Array)
#2 src/hello_world.php(130): Google\Cloud\Bigtable\Table->readRow('greeting0', Array)
#3 {main}
  thrown in vendor/google/gax/src/Serializer.php on line 149

This takes place in the test bigtableTest::testHelloWorld

Fixed in d9c4fd0