Make --repair-path also repair corrupt optimised links

There already existed a smoke test for the link content length,
but it appears that there exists some corruptions pernicious enough
to replace the file content with zeros, and keeping the same length.

--repair-path now goes as far as checking the content of the link,
making it true to its name and actually repairing the path for such
coruption cases.

1 files changed, 4 insertions, 3 deletions

diff --git a/src/libstore/local-store.hh b/src/libstore/local-store.hh
index 115ea046a..04698ba07 100644
--- a/src/libstore/local-store.hh
+++ b/src/libstore/local-store.hh
@@ -172,8 +172,9 @@ public:
 
     void optimiseStore() override;
 
-    /* Optimise a single store path. */
-    void optimisePath(const Path & path);
+    /* Optimise a single store path. Optionally, test the encountered
+       symlinks for corruption. */
+    void optimisePath(const Path & path, bool repair);
 
     bool verifyStore(bool checkContents, RepairFlag repair) override;
 
@@ -253,7 +254,7 @@ private:
 
     InodeHash loadInodeHash();
     Strings readDirectoryIgnoringInodes(const Path & path, const InodeHash & inodeHash);
-    void optimisePath_(Activity * act, OptimiseStats & stats, const Path & path, InodeHash & inodeHash);
+    void optimisePath_(Activity * act, OptimiseStats & stats, const Path & path, InodeHash & inodeHash, bool repair);
 
     // Internal versions that are not wrapped in retry_sqlite.
     bool isValidPath_(State & state, const StorePath & path);