Hadrian: 'need' source files for various docs in Rules.Documentation

Previously, changing one of the .rst files from the user guide would not cause
the user guide to be rebuilt. This patch take a first stab at declaring the
documentation source files that our documentation rules depend on, focusing
on the .rst files only for now.

We eventually might want to rebuild docs when we, say, change the haddock style
file, but this level of tracking isn't really necessary for now.

This fixes #16645.

1 files changed, 6 insertions, 0 deletions

diff --git a/hadrian/src/Rules/Documentation.hs b/hadrian/src/Rules/Documentation.hs
index 466e81c6fc..a70b4d5c9d 100644
--- a/hadrian/src/Rules/Documentation.hs
+++ b/hadrian/src/Rules/Documentation.hs
@@ -138,6 +138,9 @@ buildSphinxHtml path = do
     root <- buildRootRules
     root -/- htmlRoot -/- path -/- "index.html" %> \file -> do
         let dest = takeDirectory file
+            rstFilesDir = pathPath path
+        rstFiles <- getDirectoryFiles rstFilesDir ["**/*.rst"]
+        need (map (rstFilesDir -/-) rstFiles)
         build $ target docContext (Sphinx Html) [pathPath path] [dest]
 
 ------------------------------------ Haddock -----------------------------------
@@ -242,6 +245,9 @@ buildSphinxPdf path = do
     root <- buildRootRules
     root -/- pdfRoot -/- path <.> "pdf" %> \file -> do
         withTempDir $ \dir -> do
+            let rstFilesDir = pathPath path
+            rstFiles <- getDirectoryFiles rstFilesDir ["**/*.rst"]
+            need (map (rstFilesDir -/-) rstFiles)
             build $ target docContext (Sphinx Latex) [pathPath path] [dir]
             build $ target docContext Xelatex [path <.> "tex"] [dir]
             copyFileUntracked (dir -/- path <.> "pdf") file