threads / patch / 50997

patchcommit-graph: improve error messages

Subject: [PATCH 0/1] commit-graph: improve error messages

## tl;dr

3 messages between Apr 26, 2019 and Apr 26, 2019. Diffs are folded; open one to read it.

replies: 2people: 2as markdown or json

Derrick Stolee via GitGitGadget· Apr 26, 2019, 11:48 UTC · lore

Here is a small patch that revises the error messages from ab/commit-graph-fixes, as recommended by Ævar. Hopefully, it can be merged faster than the commit-graph v2 stuff, and I can update that series to include this change if we agree it is a good one.

Thanks, -Stolee
Cc: avarab@gmail.com
In-Reply-To: 878svxrwsh.fsf@evledraar.gmail.com
[878svxrwsh.fsf@evledraar.gmail.com]
Derrick Stolee (1):
  commit-graph: improve error messages
 commit-graph.c          | 10 +++++-----
 t/t5318-commit-graph.sh |  6 +++---
 2 files changed, 8 insertions(+), 8 deletions(-)
base-commit: 93b4405ffe4ad9308740e7c1c71383bfc369baaa
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-181%2Fderrickstolee%2Fgraph%2Fmessage-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-181/derrickstolee/graph/message-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/181
-- 
gitgitgadget
Derrick Stolee via GitGitGadget· Apr 26, 2019, 11:48 UTC · re: Derrick Stolee via GitGitGadget · lore

[PATCH 1/1] commit-graph: improve error messages

From: Derrick Stolee <dstolee@microsoft.com>
The error messages when reading a commit-graph have a few problems:
1. Some values are output in hexadecimal, but that is not made
   clear by the message. Prepend "0x" to these values.
2. The version number does not need to be hexadecimal, and also
   should mention a "maximum supported version". This has one
   possible confusing case: we could have a corrupt commit-graph
   file with version number zero, so the output would be
   "commit-graph has version 0, our maximum supported version is 1"
   This will only happen with corrupt data. This error message is
   designed instead for the case where a client is downgraded after
   writing a newer file version.
Update t5318-commit-graph.sh to watch for these new error messages.
Reported-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 commit-graph.c          | 10 +++++-----
 t/t5318-commit-graph.sh |  6 +++---
 2 files changed, 8 insertions(+), 8 deletions(-)
Show changes to 2 files +8 −8

commit-graph.c, t/t5318-commit-graph.sh

diff --git a/commit-graph.c b/commit-graph.c
index 66865acbd7..aba591913e 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -167,21 +167,21 @@ struct commit_graph *parse_commit_graph(void *graph_map, int fd,
 
 	graph_signature = get_be32(data);
 	if (graph_signature != GRAPH_SIGNATURE) {
-		error(_("commit-graph signature %X does not match signature %X"),
+		error(_("commit-graph signature 0x%X does not match signature 0x%X"),
 		      graph_signature, GRAPH_SIGNATURE);
 		return NULL;
 	}
 
 	graph_version = *(unsigned char*)(data + 4);
 	if (graph_version != GRAPH_VERSION) {
-		error(_("commit-graph version %X does not match version %X"),
+		error(_("commit-graph has version %d, our maximum supported version is %d"),
 		      graph_version, GRAPH_VERSION);
 		return NULL;
 	}
 
 	hash_version = *(unsigned char*)(data + 5);
 	if (hash_version != oid_version()) {
-		error(_("commit-graph hash version %X does not match version %X"),
+		error(_("commit-graph has hash version %d, our maximum supported version is %d"),
 		      hash_version, oid_version());
 		return NULL;
 	}
@@ -215,7 +215,7 @@ struct commit_graph *parse_commit_graph(void *graph_map, int fd,
 		chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
 
 		if (chunk_offset > graph_size - the_hash_algo->rawsz) {
-			error(_("commit-graph improper chunk offset %08x%08x"), (uint32_t)(chunk_offset >> 32),
+			error(_("commit-graph improper chunk offset 0x%08x%08x"), (uint32_t)(chunk_offset >> 32),
 			      (uint32_t)chunk_offset);
 			free(graph);
 			return NULL;
@@ -252,7 +252,7 @@ struct commit_graph *parse_commit_graph(void *graph_map, int fd,
 		}
 
 		if (chunk_repeated) {
-			error(_("commit-graph chunk id %08x appears multiple times"), chunk_id);
+			error(_("commit-graph chunk id 0x%08x appears multiple times"), chunk_id);
 			free(graph);
 			return NULL;
 		}
diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index e80c1cac02..264ebb15b1 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -420,17 +420,17 @@ test_expect_success 'detect too small' '
 
 test_expect_success 'detect bad signature' '
 	corrupt_graph_and_verify 0 "\0" \
-		"graph signature"
+		"commit-graph signature"
 '
 
 test_expect_success 'detect bad version' '
 	corrupt_graph_and_verify $GRAPH_BYTE_VERSION "\02" \
-		"graph version"
+		"commit-graph has version"
 '
 
 test_expect_success 'detect bad hash version' '
 	corrupt_graph_and_verify $GRAPH_BYTE_HASH "\02" \
-		"hash version"
+		"commit-graph has hash version"
 '
 
 test_expect_success 'detect low chunk count' '
-- 
gitgitgadget
Ævar Arnfjörð Bjarmason· Apr 26, 2019, 12:33 UTC · re: Derrick Stolee via GitGitGadget · lore

Re: [PATCH 1/1] commit-graph: improve error messages

On Fri, Apr 26 2019, Derrick Stolee via GitGitGadget wrote:
Show 15 quoted lines
> The error messages when reading a commit-graph have a few problems:
>
> 1. Some values are output in hexadecimal, but that is not made
>    clear by the message. Prepend "0x" to these values.
>
> 2. The version number does not need to be hexadecimal, and also
>    should mention a "maximum supported version". This has one
>    possible confusing case: we could have a corrupt commit-graph
>    file with version number zero, so the output would be
>
>    "commit-graph has version 0, our maximum supported version is 1"
>
>    This will only happen with corrupt data. This error message is
>    designed instead for the case where a client is downgraded after
>    writing a newer file version.
This looks good to me and is obviously correct:
Show 27 quoted lines
> Update t5318-commit-graph.sh to watch for these new error messages.
> [...]
> diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
> index e80c1cac02..264ebb15b1 100755
> --- a/t/t5318-commit-graph.sh
> +++ b/t/t5318-commit-graph.sh
> @@ -420,17 +420,17 @@ test_expect_success 'detect too small' '
>
>  test_expect_success 'detect bad signature' '
>  	corrupt_graph_and_verify 0 "\0" \
> -		"graph signature"
> +		"commit-graph signature"
>  '
>
>  test_expect_success 'detect bad version' '
>  	corrupt_graph_and_verify $GRAPH_BYTE_VERSION "\02" \
> -		"graph version"
> +		"commit-graph has version"
>  '
>
>  test_expect_success 'detect bad hash version' '
>  	corrupt_graph_and_verify $GRAPH_BYTE_HASH "\02" \
> -		"hash version"
> +		"commit-graph has hash version"
>  '
>
>  test_expect_success 'detect low chunk count' '
Just a small nit/OCD :).
The only change to that test code that's actually needed is just doing:
    -               "graph version"
    +               "graph has version"

The rest were already grepping subsets of the message before/after, and maybe worth it to keep it consistent that all these "corrupt_graph_and_verify" invocations grep the part of the message that isn't the "commit-graph <whatever>", i.e. now with just that change:

    $ git grep -h -A1 corrupt_graph_and_verify|grep -o '".*"$'
    "graph signature"
    "graph has version"
    "hash version"
    "missing the .* chunk"
    "missing the OID Fanout chunk"
    "missing the OID Lookup chunk"
    "missing the Commit Data chunk"
    "fanout value"
    "fanout value"
    "incorrect OID order"
    "from object database"
    "root tree OID for commit"
    "invalid parent"
    "is too long"
    "commit-graph parent for"
    "generation for commit"
    "non-zero generation number"
    "commit date"
    "invalid parent"
    "incorrect checksum"
Well, there's the sore thumb of "commit-graph parent for".

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