Warn about 00-index vs 01-index commercialhaskell#3520

tswelsh · Nov 7, 2017 · d1e877c · d1e877c
1 parent 1d82afa
commit d1e877c
Showing 1 changed file with 7 additions and 0 deletions.
diff --git a/doc/yaml_configuration.md b/doc/yaml_configuration.md
@@ -401,6 +401,13 @@ gpg-verify: false
 
 Will now be ignored.
 
+__IMPORTANT__ Hackage and its mirrors typically have two index files
+available: `00-index.tar.gz` and `01-index.tar.gz`. The former is a
+legacy file for backwards compatibility. It does not contain the cabal
+file revisions produced by Hackage, and therefore _will not work_ with
+most snapshots. Instead, you need to use `01-index.tar.gz` to ensure
+that exact revisions can be found, ensuring more reproducible builds.
+
 ### system-ghc
 
 Enables or disables using the GHC available on the PATH.