list missing block hashes when --verbose is enabled (#512)

2 files changed, 15 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1bd1f7c8a..2b71f3f0a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -49,6 +49,7 @@
 - Improvement: Cancelling oplog import is now more responsive during initial phase
 - Improvement: Chunk block generation for `zen oplog-export` and `zen builds upload` command are now limited to max 4000 chunks per block
 - Improvement: Added additional validation of compact binary objects when reading from disk/receiving from client
+- Improvement: If blocks metadata is missing for a download `--verbose` will enable output of all the missing chunk block hashes
 - Feature: Options `--allow-partial-block-requests` for `zen builds download` command has been augmented with two new modes, `zencacheonly` and `mixed`. Defaults to `mixed`.
   - `false` only full block requests allowed
   - `mixed`  multiple partial block ranges requests per block allowed to zen cache, single partial block range request per block to host
diff --git a/src/zen/cmds/builds_cmd.cpp b/src/zen/cmds/builds_cmd.cpp
index fee2adaee..4ad5d2b15 100644
--- a/src/zen/cmds/builds_cmd.cpp
+++ b/src/zen/cmds/builds_cmd.cpp
@@ -9051,6 +9051,20 @@ namespace {
 				std::string ErrorDescription =
 					fmt::format("All required blocks could not be found, {} blocks does not have metadata in this context.",
 								BlockRawHashes.size() - OutBlockDescriptions.size());
+				if (IsVerbose)
+				{
+					for (const IoHash& BlockHash : BlockRawHashes)
+					{
+						if (auto It = std::find_if(
+								OutBlockDescriptions.begin(),
+								OutBlockDescriptions.end(),
+								[BlockHash](const ChunkBlockDescription& Description) { return Description.BlockHash == BlockHash; });
+							It == OutBlockDescriptions.end())
+						{
+							ErrorDescription += fmt::format("\n    {}", BlockHash);
+						}
+					}
+				}
 				if (AttemptFallback)
 				{
 					ZEN_CONSOLE_WARN("{} Attemping fallback options.", ErrorDescription);