git/list[1] front-page[2] threads[3] people[4] search[5] about
 

[PATCH 1/2] gitattributes: demonstrate that Git tries to read a bogus file

From
Johannes Schindelin <johannes.schindelin@gmx.de>
Date
May 15, 2017, 15:23 UTC
Message-ID
<8d5e663dc74241176219a51e75624549668373f1.1494861793.git.johannes.schindelin@gmx.de>
In-Reply-To
<cover.1494861793.git.johannes.schindelin@gmx.de>
This problem has been reported originally in August 2015, as
	https://github.com/git-for-windows/git/issues/255

The symptom: when passing <commit>:<directory>/<file> style arguments to `git diff`, Git tries to read the attributes from a file called <commit>:<directory>/.gitattributes.

This symptom is more prominent on Windows because the colon in the file name is illegal, and therefore reported to the user. On Linux, the colon is legal, and it just so happens that that file typically does not exist, and therefore there are no adverse consequences.

However, it is still a bug: Git should not even attempt to open that file. Let's add a test case to demonstrate that problem, even on Linux and MacOSX.

The underlying problem will be really tricky to fix: the run_diff*() family of functions expects the path passed via the diff_filespec structs to be the path as if it were in the worktree. However, when processing the `git diff <blob1> <blob2>` invocation, Git uses setup_revisions()'s parsing of the pending objects to fill in this information, and setup_revisions() simply copies the command-line argument, rather than reconstructing the actual *file* path.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 t/t0003-attributes.sh | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
diff --git a/t/t0003-attributes.sh b/t/t0003-attributes.sh
index f19ae4f8ccd..a7820022d8d 100755
--- a/t/t0003-attributes.sh
+++ b/t/t0003-attributes.sh
@@ -323,4 +323,25 @@ test_expect_success 'bare repository: test info/attributes' '
 	)
 '
 
+test_expect_failure 'a file <commit>:.gitattributes is ignored' '
+	git init bogus-file &&
+	(
+		cd bogus-file &&
+		mkdir sub &&
+		test_commit sub/file &&
+		test_commit sub/file2 &&
+		commit=$(git rev-parse HEAD) &&
+		if test_have_prereq !MINGW
+		then
+			# Windows does not support colons in filenames
+			mkdir $commit:sub &&
+			echo "* -inva/id" >$commit:sub/.gitattributes
+		fi &&
+		git diff $commit:sub/file.t..$commit:sub/file2.t >out 2>err &&
+		! grep "is not a valid attribute name" err &&
+		# On Windows, there will be a warning because of the colon
+		! grep "warning: unable to access .$commit:sub" err
+	)
+'
+
 test_done
-- 
2.13.0.windows.1
Previous: Johannes SchindelinNext: Johannes Schindelin
Message 2 of 33 in “Demonstrate and partially work around a gitattributes problem”
  1. 0/2 Demonstrate and partially work around a gitattributes problemJohannes Schindelin, May 15, 2017
  2. 1/2 gitattributes: demonstrate that Git tries to read a bogus fileJohannes Schindelin, May 15, 2017
  3. 2/2 mingw: Suppress warning that <commit>:.gitattributes does not existJohannes Schindelin, May 15, 2017
  4. Jeff KingMay 16, 2017
  5. Jeff KingMay 16, 2017
  6. Junio C HamanoMay 17, 2017
  7. Jeff KingMay 17, 2017
  8. Johannes SchindelinMay 18, 2017
  9. Jeff KingMay 19, 2017
  10. 0/15 retain blob info for git diff HEAD:foo HEAD:barJeff King, May 19, 2017
  11. 01/15 handle_revision_arg: reset "dotdot" consistentlyJeff King, May 19, 2017
  12. Philip OakleyMay 20, 2017
  13. Jeff KingMay 23, 2017
  14. Philip OakleyMay 23, 2017
  15. 02/15 handle_revision_arg: simplify commit reference lookupsJeff King, May 19, 2017
  16. 03/15 handle_revision_arg: stop using "dotdot" as a generic pointerJeff King, May 19, 2017
  17. Junio C HamanoMay 24, 2017
  18. Jeff KingMay 24, 2017
  19. 04/15 handle_revision_arg: hoist ".." check out of range parsingJeff King, May 19, 2017
  20. 05/15 handle_revision_arg: add handle_dotdot() helperJeff King, May 19, 2017
  21. Junio C HamanoMay 24, 2017
  22. 06/15 sha1_name: consistently refer to object_context as "oc"Jeff King, May 19, 2017
  23. 07/15 get_sha1_with_context: always initialize oc->symlink_pathJeff King, May 19, 2017
  24. 08/15 get_sha1_with_context: dynamically allocate oc->pathJeff King, May 19, 2017
  25. 09/15 t4063: add tests of direct blob diffsJeff King, May 19, 2017
  26. 10/15 handle_revision_arg: record modes for "a..b" endpointsJeff King, May 19, 2017
  27. 11/15 handle_revision_arg: record paths for pending objectsJeff King, May 19, 2017
  28. 12/15 diff: pass whole pending entry in blobinfoJeff King, May 19, 2017
  29. 13/15 diff: use the word "path" instead of "name" for blobsJeff King, May 19, 2017
  30. 14/15 diff: use pending "path" if it is availableJeff King, May 19, 2017
  31. 15/15 diff: use blob path for blob/file diffsJeff King, May 19, 2017
  32. Junio C HamanoMay 24, 2017
  33. Jeff KingMay 24, 2017

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.