cli/command/image/build: deprecate IsArchive utility

It was only used internally.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cli/command/image/build/context.go

@@ -108,7 +108,7 @@ func DetectArchiveReader(input io.ReadCloser) (rc io.ReadCloser, ok bool, err er
 		return nil, false, fmt.Errorf("failed to peek context header from STDIN: %w", err)
 	}
 
-	return newReadCloserWrapper(buf, func() error { return input.Close() }), IsArchive(magic), nil
+	return newReadCloserWrapper(buf, func() error { return input.Close() }), isArchive(magic), nil
 }
 
 // WriteTempDockerfile writes a Dockerfile stream to a temporary file with a
@@ -178,7 +178,15 @@ func GetContextFromReader(rc io.ReadCloser, dockerfileName string) (out io.ReadC
 
 // IsArchive checks for the magic bytes of a tar or any supported compression
 // algorithm.
+//
+// Deprecated: this utility was used internally and will be removed in the next release.
 func IsArchive(header []byte) bool {
+	return isArchive(header)
+}
+
+// isArchive checks for the magic bytes of a tar or any supported compression
+// algorithm.
+func isArchive(header []byte) bool {
 	if compression.Detect(header) != compression.None {
 		return true
 	}

cli/command/image/build/context_test.go

@@ -291,7 +291,7 @@ func TestIsArchive(t *testing.T) {
 	}
 	for _, tc := range tests {
 		t.Run(tc.doc, func(t *testing.T) {
-			assert.Check(t, is.Equal(tc.expected, IsArchive(tc.header)), tc.doc)
+			assert.Check(t, is.Equal(tc.expected, isArchive(tc.header)), tc.doc)
 		})
 	}
 }