From: Daan De Meyer <daan.j.demeyer@gmail.com>
Date: Thu, 24 Aug 2023 14:19:41 +0000 (+0200)
Subject: Drop list reset on empty value
X-Git-Tag: v16~38
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cae52912e06cce8f145feabe685e601f9c4ed177;p=thirdparty%2Fmkosi.git

Drop list reset on empty value

This does not work properly with python's configparser, which will
insert empty lines when doing something like the following:

```
Packages=
       abc
```

Instead, we restore the "!" operator for lists to remove values from
the list as it did originally instead of preventing values from being
added.
---

diff --git a/NEWS.md b/NEWS.md
index f72d4d4cb..20d75e7dc 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -6,8 +6,8 @@
   well following the usual config precedence logic
 - The "first assignment wins" logic was dropped from configuration
   parsing. Settings parsed later will now override earlier values and
-  the `!` exclusion logic for lists was removed. Assigning the empty
-  string to a list can be used to clear previously assigned values.
+  the `!` operator for lists will now remove values already in the list
+  instead of preventing specific values from being added.
 
 ## v15.1
 
diff --git a/mkosi/config.py b/mkosi/config.py
index 5ee5492f6..99040dfcc 100644
--- a/mkosi/config.py
+++ b/mkosi/config.py
@@ -358,9 +358,12 @@ def config_make_list_parser(delimiter: str,
 
         for v in values:
             if not v:
-                new = []
                 continue
 
+            if v.startswith("!"):
+                v = v[1:]
+                new = [n for n in new if not fnmatch.fnmatchcase(v, n)]
+
             new.append(parse(v))
 
         return new
diff --git a/mkosi/resources/mkosi.md b/mkosi/resources/mkosi.md
index 9d2710ebc..2f8607008 100644
--- a/mkosi/resources/mkosi.md
+++ b/mkosi/resources/mkosi.md
@@ -272,8 +272,10 @@ setting. Also note that before v16, we used to do the opposite, where
 the earlier assignment would be used instead of later assignments.
 
 Settings that take a list of values are merged by appending the new
-values to the previously configured values. If a list setting is set to
-the empty list, all previously assigned values are cleared.
+values to the previously configured values. If a value of a list setting
+is prefixed with `!`, all existing instances of that value in the list
+are removed. Values prefixed with `!` can be globs to remove more than
+one value.
 
 To conditionally include configuration files, the `[Match]` section can
 be used. Matches can use a pipe symbol ("|") after the equals sign