feat!: Store logs under XDG_STATE_HOME instead of XDG_CACHE_HOME

https://specifications.freedesktop.org/basedir/0.8/#variables:

> The $XDG_STATE_HOME contains state data that should persist between
> (application) restarts, but that is not important or portable enough
> to the user that it should be stored in $XDG_DATA_HOME. It may
> contain:
>
> • actions history (logs, history, recently used files, …)
> • current state of the application that can be reused on a restart
>   (view, layout, open files, undo history, …)

Author: e-kwsm

cabal-install/src/Distribution/Client/Config.hs

@@ -829,7 +829,7 @@ defaultStoreDir =
 
 defaultLogsDir :: IO FilePath
 defaultLogsDir =
-  getDefaultDir XdgCache "logs"
+  getDefaultDir XdgState "logs"
 
 defaultReportsDir :: IO FilePath
 defaultReportsDir =

changelog.d/pr-12051.md

@@ -0,0 +1,9 @@
+---
+synopsis: Store logs under XDG_STATE_HOME instead of XDG_CACHE_HOME
+packages: cabal-install
+prs: #12051
+---
+
+- before: logs are stored under `${XDG_CACHE_HOME:-$HOME/.cache}/cabal/logs`
+- after: logs are stored under `${XDG_STATE_HOME:-$HOME/.local/state}/cabal/logs`
+- ref: <https://specifications.freedesktop.org/basedir/0.8/#variables>

doc/cabal-commands.rst

@@ -741,7 +741,7 @@ installed binaries, and so on.
     compiler-path: /home/alice/.ghcup/bin/ghc
     cache-home: /home/alice/.cache/cabal
     remote-repo-cache: /home/alice/.cache/cabal/packages
-    logs-dir: /home/alice/.cache/cabal/logs
+    logs-dir: /home/alice/.local/state/cabal/logs
     store-dir: /home/alice/.cache/cabal/store
     config-file: /home/alice/.config/cabal/config
     installdir: /home/alice/.cache/cabal/bin
@@ -763,7 +763,7 @@ Or using the json output:
       },
       "cache-home": "/home/alice/.cache/cabal",
       "remote-repo-cache": "/home/alice/.cache/cabal/packages",
-      "logs-dir": "/home/alice/.cache/cabal/logs",
+      "logs-dir": "/home/alice/.local/state/cabal/logs",
       "store-dir": "/home/alice/.cache/cabal/store",
       "config-file": "/home/alice/.config/cabal/config",
       "installdir": "/home/alice/.cache/cabal/bin"

doc/cabal-project-description-file.rst

@@ -1863,7 +1863,7 @@ Advanced global configuration options
                --logs-dir=DIR
     :synopsis: Directory to store build logs.
 
-    :default: ``~/.cache/cabal/logs``
+    :default: ``~/.local/state/cabal/logs``
 
     :strike:`The location where build logs for packages are stored.`
     Not implemented yet.
@@ -1874,7 +1874,7 @@ Advanced global configuration options
                --build-summary=TEMPLATE
     :synopsis: Build summaries location.
 
-    :default: ``~/.cache/cabal/logs/build.log``
+    :default: ``~/.local/state/cabal/logs/build.log``
 
     :strike:`The file to save build summaries.` Not implemented yet.