Fix large file resume refusing the large_file_sha1 it stored (#223)

.sdkharness/tests/conformance/LargeResume.java

@@ -38,11 +38,11 @@
  * <p>Two legs, because the SDK treats the two content shapes differently. Leg "no sha1": the content source does
  * not know its sha1, so the large file carries no large_file_sha1 and the rerun is the same request as the first
  * run. Leg "sha1": the content source knows its sha1 (the SDK records it as the large_file_sha1 file info); the
- * rerun is again the same request as the first run. If the SDK refuses it with a "mismatch" error, the scenario
- * FAILS with a FINDING as the reason: the check detects, it does not work around the refusal. The finding is about
- * the SDK, not about B2: B2LargeFileUploader removes the key
- * {@code X-Bz-Info-large_file_sha1} (B2Headers.LARGE_FILE_SHA1) from the file info before comparing it with the
- * request's, but the info map is keyed {@code large_file_sha1} (B2Headers.LARGE_FILE_SHA1_INFO_NAME).
+ * rerun is again the same request as the first run, and the SDK must accept it. An earlier SDK version refused it
+ * with a "mismatch" error, because B2LargeFileUploader removed the key {@code X-Bz-Info-large_file_sha1}
+ * (B2Headers.LARGE_FILE_SHA1) from the stored file info before comparing it with the request's, while the info map
+ * is keyed {@code large_file_sha1} (B2Headers.LARGE_FILE_SHA1_INFO_NAME). This leg fails with a FINDING as the
+ * reason if that refusal comes back; the check detects, it does not work around the refusal.
  */
 public class LargeResume {
     private static final int PARTS = 4;

CHANGELOG.md

@@ -7,6 +7,9 @@
   A missing or empty signature header throws `B2SignatureVerificationException`; a null or empty signing secret throws `IllegalArgumentException`.
 * Signature comparison is now constant-time.
 
+### Fixed
+* `finishUploadingLargeFile` no longer throws a local `mismatch` error when resuming a large file whose content source knows its sha1.
+
 ### Added
 * Added `B2EventNotification.parseUnverified`, which parses without checking a signature. The one-argument `parse` overloads are deprecated in its favor.
 

core/src/main/java/com/backblaze/b2/client/B2LargeFileUploader.java

@@ -138,7 +138,8 @@ B2FileVersion finishUploadingLargeFile(B2FileVersion largeFileVersion,
         final Map<String,String> infos = new TreeMap<>();
         //noinspection CollectionAddAllCanBeReplacedWithConstructor
         infos.putAll(largeFileVersion.getFileInfo());
-        infos.remove(B2Headers.LARGE_FILE_SHA1);
+        // the stored file info is keyed by the bare name, "large_file_sha1", not by the "X-Bz-Info-" header name.
+        infos.remove(B2Headers.LARGE_FILE_SHA1_INFO_NAME);
         throwIfMismatch("fileInfo", toString(request.getFileInfo()), toString(infos));
     }
 

core/src/test/java/com/backblaze/b2/client/B2LargeFileUploaderTest.java

@@ -370,6 +370,59 @@ public void testThrowIfLargeFileVersionDoesntSeemToMatchRequest_mismatchingSha1(
         B2LargeFileUploader.throwIfLargeFileVersionDoesntSeemToMatchRequest(largeFileVersion, contentSource.getContentLength(), request);
     }
 
+    @Test
+    public void testThrowIfLargeFileVersionDoesntSeemToMatchRequest_matchingSha1IsNotAFileInfoMismatch() throws IOException, B2Exception {
+        // the SDK stores the sha1 of a large file as the file info "large_file_sha1" when it starts the file.
+        // that entry is checked as the sha1, so it must not also count as an unexpected file info entry.
+        when(contentSource.getSha1OrNull()).thenReturn(makeSha1(1));
+        final B2UploadFileRequest request = B2UploadFileRequest
+                .builder(bucketId(1), fileName(2), B2ContentTypes.APPLICATION_OCTET, contentSource)
+                .build();
+        final B2FileVersion largeFileVersion = new B2FileVersion(
+                fileId(1),
+                fileName(2),
+                contentSource.getContentLength(),
+                B2ContentTypes.APPLICATION_OCTET,
+                null,
+                null,
+                B2Collections.mapOf(B2Headers.LARGE_FILE_SHA1_INFO_NAME, makeSha1(1)),
+                "action",
+                1234,
+                null,
+                null,
+                null,
+                null);
+
+        // does not throw.
+        B2LargeFileUploader.throwIfLargeFileVersionDoesntSeemToMatchRequest(largeFileVersion, contentSource.getContentLength(), request);
+    }
+
+    @Test
+    public void testThrowIfLargeFileVersionDoesntSeemToMatchRequest_otherFileInfoStillMismatches() throws IOException, B2Exception {
+        when(contentSource.getSha1OrNull()).thenReturn(makeSha1(1));
+        final B2UploadFileRequest request = B2UploadFileRequest
+                .builder(bucketId(1), fileName(2), B2ContentTypes.APPLICATION_OCTET, contentSource)
+                .build();
+        final B2FileVersion largeFileVersion = new B2FileVersion(
+                fileId(1),
+                fileName(2),
+                contentSource.getContentLength(),
+                B2ContentTypes.APPLICATION_OCTET,
+                null,
+                null,
+                B2Collections.mapOf(B2Headers.LARGE_FILE_SHA1_INFO_NAME, makeSha1(1), "color", "blue"),
+                "action",
+                1234,
+                null,
+                null,
+                null,
+                null);
+
+        thrown.expect(B2LocalException.class);
+        thrown.expectMessage("contentSource has fileInfo");
+        B2LargeFileUploader.throwIfLargeFileVersionDoesntSeemToMatchRequest(largeFileVersion, contentSource.getContentLength(), request);
+    }
+
     @Test
     public void testThrowIfLargeFileVersionDoesntSeemToMatchRequest_mismatchingContentType() throws IOException, B2Exception {
         final B2UploadFileRequest request = B2UploadFileRequest