Merge pull request #1946 from restic/fix-1945

Remove truncated files from cache

changelog/unreleased/issue-1935

@@ -0,0 +1,8 @@
+Bugfix: Remove truncated files from cache
+
+When a file in the local cache is truncated, and restic tries to access data
+beyond the end of the (cached) file, it used to return an error "EOF". This is
+now fixed, such truncated files are removed and the data is fetched directly
+from the backend.
+
+https://github.com/restic/restic/issues/1935

internal/cache/file.go

@@ -63,6 +63,12 @@ func (c *Cache) Load(h restic.Handle, length int, offset int64) (io.ReadCloser,
 		return nil, errors.Errorf("cached file %v is truncated, removing", h)
 	}
 
+	if fi.Size() < offset+int64(length) {
+		_ = f.Close()
+		_ = c.Remove(h)
+		return nil, errors.Errorf("cached file %v is too small, removing", h)
+	}
+
 	if offset > 0 {
 		if _, err = f.Seek(offset, io.SeekStart); err != nil {
 			_ = f.Close()

internal/cache/file_test.go

@@ -218,7 +218,7 @@ func TestFileLoad(t *testing.T) {
 		{32*1024 + 5, 0},
 		{0, 123},
 		{0, 64*1024 + 234},
-		{100, 5234142},
+		{100, 5234142 - 100},
 	}
 
 	for _, test := range tests {