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Author: zlonast

Cabal/src/Distribution/Simple/Setup/Config.hs

@@ -572,12 +572,12 @@ configureOptions showOrParseArgs =
           "optimization"
           configOptimization
           (\v flags -> flags{configOptimization = v})
-          [ reqArg'
+          [ optArg'
               "n"
-              (Flag . fromString)
+              (Flag . fromMaybe noFlagValue . fmap fromString)
               ( \case
                   NoFlag -> []
-                  Flag flag -> [O.toString flag]
+                  Flag flag -> [Just $ O.toString flag]
               )
               "O"
               ["enable-optimization", "enable-optimisation"]
@@ -592,12 +592,12 @@ configureOptions showOrParseArgs =
           "debug-info"
           configDebugInfo
           (\v flags -> flags{configDebugInfo = v})
-          [ reqArg'
+          [ optArg'
               "n"
-              (Flag . fromString)
+              (Flag . fromMaybe noFlagValue . fmap fromString)
               ( \case
                   NoFlag -> []
-                  Flag flag -> [D.toString flag]
+                  Flag flag -> [Just $ D.toString flag]
               )
               "g"
               ["enable-debug-info"]

changelog.d/11937.md

@@ -8,6 +8,14 @@ The rendering of certain boolean‑like flags has been changed to use numeric le
 - For the `-O` (optimisation) flag, `True` or an unspecified value now renders as `1`, while `False` renders as `0`.
 - For the `-g` (debug info) flag, `True` or an unspecified value now renders `2`, while `False` renders as `0`.
 This makes the displayed compiler flags more consistent with their internal semantics (e.g. optimisation level 1 is the default).
-- The `-g` flag is being repurposed to exclusively control debug information,
-  aligning it with common build system conventions. Previously, `-g` served as
-  an alias for `--ghc`. Please use the explicit `--ghc` flag instead.
+- Removes the short `-g` option for the `--ghc` flag. This is now used as the short option for `--enable-debug-info`.
+```diff
+  $ cabal build --help
+...
+- -g, --ghc                      compile with GHC
++ --ghc                          compile with GHC
+...
+- --enable-debug-info[=n]        Emit debug info (n is 0--3, default is 0)
++ -g n or -gn, --enable-debug-info[=n]
++                                Emit debug info (n is 0--3, default is 0)
+```