docs(gotchas): Overriding libssh2 (#411)

Author: shivaraj-bh

doc/gotchas.md

@@ -0,0 +1,30 @@
+# Gotchas
+
+{#libssh2}
+## Overriding `libssh2` Haskell library
+
+Overriding the package with `packages.libssh2.source = "0.2.0.9"` results in infinite recursion.
+
+Possibly having to do with `cabal2nix` not understanding that [`libssh2` in `pkgconfig-depends` of `libssh2.cabal`](https://github.com/portnov/libssh2-hs/blob/bf7cbe643c7f4fb4fad3963705feb8351471eb01/libssh2/libssh2.cabal#L70)
+is not self-referential.
+
+Use the following [[settings]] configuration to override `libssh2`:
+
+```nix
+# In `haskellProjects.default`
+{
+  settings = {
+    libssh2 = {
+      broken = false;
+      custom = (p: p.overrideAttrs (oa: rec {
+        version = "0.2.0.9";
+        src = pkgs.fetchzip {
+          url = "mirror://hackage/${oa.pname}-${version}/${oa.pname}-${version}.tar.gz";
+          sha256 = "sha256-/zzj11iOxkpEsKVwB4+IF8dNZwEuwUlgw+cZYguN8QI=";
+        };
+      }));
+    };
+  };
+}
+```
+

doc/package-set.md

@@ -60,3 +60,8 @@ Finally, you can externalize this `ghc810` package set as either a flake-parts m
 ## Examples
 
 - https://github.com/nammayatri/common/pull/11/files
+
+## See also
+
+- [[gotchas]]
+