fix export overwrite on FAT

Don't accept the cid of the temp file that the content has just been
written to as something we will accept if another file has that same
content. There's no reason to, and on FAT, due to mtime resolution,
the test suite hit just such a case.

This fixes a reversion from 73df633a6215faa093e4a7524c6d328aa988aed1
which removed inode from the ContentIdentifier.

diff --git a/Remote/Directory.hs b/Remote/Directory.hs
index c4f8dcf45d1ccc2bb237e09056a84f5f377f33d1..58c91edfc91a568dfd05b2fbd29bfb7629339d69 100644 (file)
--- a/Remote/Directory.hs
+++ b/Remote/Directory.hs
@@ -471,7 +471,7 @@ storeExportWithContentIdentifierM dir src _k loc overwritablecids p = do
                        Nothing -> giveup "unable to generate content identifier"
                        Just newcid -> do
                                checkExportContent dir loc
-                                       (newcid:overwritablecids)
+                                       overwritablecids
                                        (giveup "unsafe to overwrite file")
                                        (const $ liftIO $ rename tmpf dest)
                                return newcid

diff --git a/doc/bugs/export__95__import_fails_on_crippled_FS_on_ubuntu.mdwn b/doc/bugs/export__95__import_fails_on_crippled_FS_on_ubuntu.mdwn
index 4ed5427cd9bca76a270dd38b66b312cb7f83555f..ea1b42dac2ba1b23e436c160c3fbe8779ea223d7 100644 (file)
--- a/doc/bugs/export__95__import_fails_on_crippled_FS_on_ubuntu.mdwn
+++ b/doc/bugs/export__95__import_fails_on_crippled_FS_on_ubuntu.mdwn
@@ -26,3 +26,5 @@ on 8.20201129+git169-gaa07e68ed-1~ndall+1 (presumably... identified 3 regression
 
 [[!meta author=yoh]]
 [[!tag projects/datalad]]
+
+> [[fixed|done]] --[[Joey]]

diff --git a/doc/bugs/export__95__import_fails_on_crippled_FS_on_ubuntu/comment_3_d949841feb6a035e20a3d0f31634d388._comment b/doc/bugs/export__95__import_fails_on_crippled_FS_on_ubuntu/comment_3_d949841feb6a035e20a3d0f31634d388._comment
new file mode 100644 (file)
index 0000000..25e9d0a
--- /dev/null
+++ b/doc/bugs/export__95__import_fails_on_crippled_FS_on_ubuntu/comment_3_d949841feb6a035e20a3d0f31634d388._comment
@@ -0,0 +1,30 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 3"""
+ date="2021-01-25T16:54:58Z"
+ content="""
+Oh this is interesting:
+
+       unexport foo import
+         unsafe to remove modified file
+       failed
+       export foo import ok
+
+So despite seeing the file is modified when it is asked to remove it, it
+somehow does not notice that when writing to it, so overwrites it
+with the content anyway. That's how it ends up with
+unexpected content, despite the overall `git-annex export`
+failing as expected.
+
+And the root cause is, the test suite writes to the file on the remote,
+and then Remote.Directory writes to a temp file, and then gets its content
+identifier (mtime), and for some reason accepts that content identifier as
+one it can overwrite. Due to the timestamp resolution, that's the same
+content identifier as the newly written file on the remote. So it
+overwrites it.
+
+I can't find any good reason for it to accept the temp file's content
+identifier as a known content identifier, which it's always done. Other remotes
+don't do that. So I think this is a real bug in Remote.Directory and will
+fix it there.
+"""]]