Do not run pip check in the pip buildpack for Python 3.7

This preserves the behavior of the current build system.

PiperOrigin-RevId: 327876585
Change-Id: I5e614a0b66c26e1a3073f82389be78db022c7dc3

builders/gae/python37/acceptance/acceptance_test.go

@@ -37,6 +37,11 @@ func TestAcceptance(t *testing.T) {
 		{
 			App: "pip_dependency",
 		},
+		{
+			App: "pip_check",
+			// The warning message is cut short because it's not deterministic.
+			MustOutput: []string{`WARNING: Found incompatible dependencies: "sub-dependency-`},
+		},
 		{
 			App: "gunicorn_present",
 		},

builders/gae/python38/acceptance/acceptance_test.go

@@ -67,3 +67,26 @@ func TestAcceptance(t *testing.T) {
 		})
 	}
 }
+
+func TestFailures(t *testing.T) {
+	builder, cleanup := acceptance.CreateBuilder(t)
+	t.Cleanup(cleanup)
+
+	testCases := []acceptance.FailureTest{
+		{
+			App:       "pip_check",
+			MustMatch: `sub-dependency-\w 1\.0\.0 has requirement sub-dependency-\w.*1\.0\.0, but you.* have sub-dependency-\w 1\.0\.0`,
+		},
+	}
+
+	for _, tc := range testCases {
+		tc := tc
+		t.Run(tc.App, func(t *testing.T) {
+			t.Parallel()
+
+			tc.Env = append(tc.Env, "GOOGLE_RUNTIME=python38")
+
+			acceptance.TestBuildFailure(t, builder, tc)
+		})
+	}
+}

builders/gae/python39/acceptance/acceptance_test.go

@@ -71,3 +71,26 @@ func TestAcceptance(t *testing.T) {
 		})
 	}
 }
+
+func TestFailures(t *testing.T) {
+	builder, cleanup := acceptance.CreateBuilder(t)
+	t.Cleanup(cleanup)
+
+	testCases := []acceptance.FailureTest{
+		{
+			App:       "pip_check",
+			MustMatch: `sub-dependency-\w 1\.0\.0 has requirement sub-dependency-\w.*1\.0\.0, but you.* have sub-dependency-\w 1\.0\.0`,
+		},
+	}
+
+	for _, tc := range testCases {
+		tc := tc
+		t.Run(tc.App, func(t *testing.T) {
+			t.Parallel()
+
+			tc.Env = append(tc.Env, "GOOGLE_RUNTIME=python39")
+
+			acceptance.TestBuildFailure(t, builder, tc)
+		})
+	}
+}

builders/testdata/python/pip_check/main.py

@@ -0,0 +1,27 @@
+# Copyright 2020 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from flask import Flask
+import os
+
+app = Flask(__name__)
+
+
+@app.route('/')
+def hello():
+  return 'PASS'
+
+
+if __name__ == '__main__':
+  app.run(port=os.environ['PORT'], debug=True)

builders/testdata/python/pip_check/requirements.txt

@@ -0,0 +1,2 @@
+flask==1.1.1
+diamond-dependency==1.0.0  # This package will fail a build with pip check.

cmd/python/pip/main.go

@@ -19,6 +19,7 @@ package main
 import (
 	"fmt"
 	"os"
+	"strings"
 
 	"github.com/GoogleCloudPlatform/buildpacks/pkg/cache"
 	gcp "github.com/GoogleCloudPlatform/buildpacks/pkg/gcpbuildpack"
@@ -68,11 +69,19 @@ func buildFn(ctx *gcp.Context) error {
 
 	l.SharedEnvironment.PrependPath("PYTHONPATH", l.Path)
 
-	// Check for broken dependencies.
 	ctx.Logf("Checking for incompatible dependencies.")
-	checkDeps := ctx.Exec([]string{"python3", "-m", "pip", "check"}, gcp.WithEnv("PYTHONPATH="+l.Path+":"+os.Getenv("PYTHONPATH")), gcp.WithUserAttribution)
-	if checkDeps.ExitCode != 0 {
-		return fmt.Errorf("incompatible dependencies installed: %q", checkDeps.Stdout)
+	result, err := ctx.ExecWithErr([]string{"python3", "-m", "pip", "check"}, gcp.WithEnv("PYTHONPATH="+l.Path+":"+os.Getenv("PYTHONPATH")), gcp.WithUserAttribution)
+	if result == nil {
+		return fmt.Errorf("pip check: %w", err)
 	}
-	return nil
+	if result.ExitCode == 0 {
+		return nil
+	}
+	// HACK: For backwards compatibility on App Engine and Cloud Functions Python 3.7 only report a warning.
+	if strings.HasPrefix(python.Version(ctx), "Python 3.7") {
+		ctx.Warnf("Found incompatible dependencies: %q", result.Stdout)
+		return nil
+	}
+	return fmt.Errorf("found incompatible dependencies: %q", result.Stdout)
+
 }

pkg/python/python.go

@@ -38,7 +38,7 @@ const (
 // Version returns the installed version of Python.
 func Version(ctx *gcp.Context) string {
 	result := ctx.Exec([]string{"python3", "--version"})
-	return strings.TrimSpace(result.Stderr)
+	return strings.TrimSpace(result.Stdout)
 }
 
 // CheckCache checks whether cached dependencies exist and match.