modules: Add some help text to the 'unknown revision' error

I had a head scratching moment with this myself, so it's safe to say that others will.

See #6825

1 files changed, 8 insertions, 1 deletions

diff --git a/modules/client.go b/modules/client.go
index 8d9bf8762..4a45c97ff 100644
--- a/modules/client.go
+++ b/modules/client.go
@@ -627,7 +627,14 @@ func (c *Client) runGo(
 
 		if strings.Contains(stderr.String(), "invalid version: unknown revision") {
 			// See https://github.com/gohugoio/hugo/issues/6825
-			c.logger.Println(`hugo: you need to manually edit go.mod to resolve the unknown revision.`)
+			c.logger.Println(`An unknown resivion most likely means that someone has deleted the remote ref (e.g. with a force push to GitHub).
+To resolve this, you need to manually edit your go.mod file and replace the version for the module in question with a valid ref.
+
+The easiest is to just enter a valid branch name ther, e.g. master, which would be the what you put in place of 'v0.5.1' in the example below.
+
+require github.com/gohugoio/hugo-mod-jslibs/instantpage v0.5.1
+
+If you then run 'hugo mod graph' it should resolve itself to the most recent version (or commit if no semver versions).`)
 		}
 
 		_, ok := err.(*exec.ExitError)