fix: warn instead of error when COPY wildcard does not match any files (#3127)

* when using wildcard hitting ResolveEnvAndWildcards ignore error when there is no file match

* adding unit test

* fix unit test wrong check in expected

* fix unit test for make sure there is no file copied

* copy with wildcard warning and success when no match file

* fix Test_IsSrcsValid since its changes the behaviour

Author: prima101112

Diff for: pkg/commands/copy_test.go

@@ -450,8 +450,9 @@ func Test_CopyEnvAndWildcards(t *testing.T) {
 
 		return testDir, filepath.Base(dir)
 	}
-	testDir, srcDir := setupDirs(t)
+
 	t.Run("copy sources into a dir defined in env variable", func(t *testing.T) {
+		testDir, srcDir := setupDirs(t)
 		defer os.RemoveAll(testDir)
 		expected, err := readDirectory(filepath.Join(testDir, srcDir))
 		if err != nil {
@@ -487,6 +488,44 @@ func Test_CopyEnvAndWildcards(t *testing.T) {
 			testutil.CheckDeepEqual(t, expected[i].Name(), f.Name())
 			testutil.CheckDeepEqual(t, expected[i].Mode(), f.Mode())
 		}
+
+	})
+
+	t.Run("copy sources into a dir defined in env variable with no file found", func(t *testing.T) {
+		testDir, srcDir := setupDirs(t)
+		defer os.RemoveAll(testDir)
+
+		targetPath := filepath.Join(testDir, "target") + "/"
+
+		cmd := CopyCommand{
+			cmd: &instructions.CopyCommand{
+				//should only dam and bam be copied
+				SourcesAndDest: instructions.SourcesAndDest{SourcePaths: []string{srcDir + "/tam[s]"}, DestPath: "$TARGET_PATH"},
+			},
+			fileContext: util.FileContext{Root: testDir},
+		}
+
+		cfg := &v1.Config{
+			Cmd:        nil,
+			Env:        []string{"TARGET_PATH=" + targetPath},
+			WorkingDir: testDir,
+		}
+
+		err := cmd.ExecuteCommand(cfg, dockerfile.NewBuildArgs([]string{}))
+		if err != nil {
+			t.Fatal(err)
+		}
+		testutil.CheckNoError(t, err)
+
+		actual, err := readDirectory(targetPath)
+
+		//check it should error out since no files are copied and targetPath is not created
+		if err == nil {
+			t.Fatal("expected error no dirrectory but got nil")
+		}
+
+		//actual should empty since no files are copied
+		testutil.CheckDeepEqual(t, 0, len(actual))
 	})
 }
 

Diff for: pkg/util/command_util.go

@@ -286,8 +286,10 @@ func IsSrcsValid(srcsAndDest instructions.SourcesAndDest, resolvedSources []stri
 			totalFiles++
 		}
 	}
+	// ignore the case where whildcards and there are no files to copy
 	if totalFiles == 0 {
-		return errors.New("copy failed: no source files specified")
+		// using log warning instead of return errors.New("copy failed: no source files specified")
+		logrus.Warn("No files to copy")
 	}
 	// If there are wildcards, and the destination is a file, there must be exactly one file to copy over,
 	// Otherwise, return an error

Diff for: pkg/util/command_util_test.go

@@ -489,7 +489,16 @@ var isSrcValidTests = []struct {
 			"ignore/baz",
 			"ignore/bar",
 		},
-		shouldErr: true,
+		shouldErr: false,
+	},
+	{
+		name: "copy two srcs, wildcard and no file match, to file",
+		srcsAndDest: []string{
+			"ignore/ba[s]",
+			"dest",
+		},
+		resolvedSources: []string{},
+		shouldErr:       false,
 	},
 }