[WARNING] unknown commit-graph chunk: 0x47444132

[TheSnoozer]

Version

6.7.0.202309050840-r

Operating System

MacOS

Bug description

When running the git-commit-id-maven-plugin (which uses jgit under the hood) a warning about unknown commit-graph chunk is reported.

This warning seems to only be reproducible under mac using a

Apache Maven 3.9.6 (bc0240f3c744dd6b6ec2920b3cd08dcc295161ae)
Maven home: /Users/khm/tools/maven
Java version: 21.0.1, vendor: Oracle Corporation, runtime: /Users/khm/.sdkman/candidates/java/21.0.1-open
Default locale: en_DE, platform encoding: UTF-8
OS name: "mac os x", version: "14.0", arch: "aarch64", family: "mac"

The message templates are defined in:

org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties:commitGraphChunkUnknown=unknown commit-graph chunk: 0x{0}

and the error observed comes from:

jgit/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/commitgraph/CommitGraphLoader.java

Lines 194 to 196 in b1cc74b

	LOG.warn(MessageFormat.format(
	JGitText.get().commitGraphChunkUnknown,
	Integer.toHexString(chunkId)));

.

Actual behavior

When running jgit a warning about an unknown commit-graph chunk is reported:

[INFO] --- git-commit-id:7.0.0:revision (default) @ tree ---
[WARNING] unknown commit-graph chunk: 0x47444132
[WARNING] unknown commit-graph chunk: 0x47444132
[WARNING] unknown commit-graph chunk: 0x47444132
[WARNING] unknown commit-graph chunk: 0x47444132

Expected behavior

No warning.

Relevant log output

No response

Other information

To reproduce checkout the branch https://github.com/khmarbaise/maven-it-extension/tree/git-commit-id-maven-plugin-issue-687
and run mvn clean verify.

Can be reproduced using:

• Maven 4.0.0-alpha-10

Apache Maven 4.0.0-alpha-10 (89d3c0321dda868c432edf504f1884e6fd706f00)
Maven home: /Users/khm/tools/maven
Java version: 21.0.1, vendor: Oracle Corporation, runtime: /Users/khm/.sdkman/candidates/java/21.0.1-open
Default locale: en_DE, platform encoding: UTF-8
OS name: "mac os x", version: "14.0", arch: "aarch64", family: "mac"

• Maven 3.9.6

Apache Maven 3.9.6 (bc0240f3c744dd6b6ec2920b3cd08dcc295161ae)
Maven home: /Users/khm/tools/maven
Java version: 21.0.1, vendor: Oracle Corporation, runtime: /Users/khm/.sdkman/candidates/java/21.0.1-open
Default locale: en_DE, platform encoding: UTF-8
OS name: "mac os x", version: "14.0", arch: "aarch64", family: "mac"

• Maven 3.8.8

mvn --version
Apache Maven 3.8.8 (4c87b05d9aedce574290d1acc98575ed5eb6cd39)
Maven home: /Users/khm/tools/maven
Java version: 21.0.1, vendor: Oracle Corporation, runtime: /Users/khm/.sdkman/candidates/java/21.0.1-open
Default locale: en_DE, platform encoding: UTF-8
OS name: "mac os x", version: "14.0", arch: "aarch64", family: "mac"

Can not be reproduced under linux and the same repository/branch/commit.

original bug-report: git-commit-id/git-commit-id-maven-plugin#687

[TheSnoozer]

I found more context on this.

Jgit's constants are defined here:

jgit/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/commitgraph/CommitGraphConstants.java

Lines 18 to 30 in b1cc74b

	static final int COMMIT_GRAPH_MAGIC = 0x43475048; /* "CGPH" */
	static final int CHUNK_ID_OID_FANOUT = 0x4f494446; /* "OIDF" */
	static final int CHUNK_ID_OID_LOOKUP = 0x4f49444c; /* "OIDL" */
	static final int CHUNK_ID_COMMIT_DATA = 0x43444154; /* "CDAT" */
	static final int CHUNK_ID_EXTRA_EDGE_LIST = 0x45444745; /* "EDGE" */
	static final int CHUNK_ID_BLOOM_FILTER_INDEX = 0x42494458; /* "BIDX" */
	static final int CHUNK_ID_BLOOM_FILTER_DATA = 0x42444154; /* "BDAT" */

This 0x47444132 seems to come from
https://github.com/git/git/blob/a26002b62827b89a19b1084bd75d9371d565d03c/commit-graph.c#L48-L49 and is simply not listed as magic value in jgit.

It was introduced with this change:
git/git@6dbf4b8

I found the relevant references on this discussion