Set errBody of defaultErrorFormatters.notFoundErrorFormatter in servant-server (#1790)

blackheaven · blackheaven · commit 1333dde3f949 · 2025-10-04T19:02:52.000+02:00
diff --git a/changelog.d/pr-1843 b/changelog.d/pr-1843
@@ -0,0 +1,7 @@
+synopsis: Set `errBody` of `defaultErrorFormatters.notFoundErrorFormatter`
+packages: servant-server
+prs: #1843
+issues: #1790
+description: {
+  Set `errBody` of `defaultErrorFormatters.notFoundErrorFormatter` to avoid an empty body.
+}
diff --git a/servant-server/src/Servant/Server/Internal/ErrorFormatter.hs b/servant-server/src/Servant/Server/Internal/ErrorFormatter.hs
@@ -48,7 +48,7 @@ defaultErrorFormatters =
     { bodyParserErrorFormatter = err400Formatter
     , urlParseErrorFormatter = err400Formatter
     , headerParseErrorFormatter = err400Formatter
-    , notFoundErrorFormatter = const err404
+    , notFoundErrorFormatter = const err404 {errBody = "404 Not Found"}
     }
 
 -- | A custom formatter for errors produced by parsing combinators like

Original file line number	Diff line number	Diff line change
`@@ -48,7 +48,7 @@ defaultErrorFormatters =`
`48`	`48`	`{ bodyParserErrorFormatter = err400Formatter`
`49`	`49`	`, urlParseErrorFormatter = err400Formatter`
`50`	`50`	`, headerParseErrorFormatter = err400Formatter`
`51`		`- , notFoundErrorFormatter = const err404`
	`51`	`+ , notFoundErrorFormatter = const err404 {errBody = "404 Not Found"}`
`52`	`52`	`}`
`53`	`53`
`54`	`54`	`-- \| A custom formatter for errors produced by parsing combinators like`