[sdk/kdesrc-build/docbook_historied_per_file] doc/kdesrc-buildrc: Fix default value for "directory-layout" option

Git commit b638608f66252e84f507afb8cd56b7f7c65c05c2 by Andrew Shark.
Committed on 09/01/2024 at 07:52.
Pushed by ashark into branch 'docbook_historied_per_file'.

Fix default value for "directory-layout" option

It was silently allowed to have unset "directory-layout" option value, that was treated as "metadata" value.

Previously, it defaulted to "metadata". Then commit 7fe7c940 (BUG: 461279) changed the default value in documentation to "flat", but not in the code.

This commit treats any incorrect value (not one of "flat", "invent", "metadata"), including empty string, as a "flat" value with warning.

Add the forgotten default BuildContext value, and add it in FirstRun.

Original commit: 642bdc2e
https://invent.kde.org/sdk/kdesrc-build/-/commit/642bdc2e326f8eae6cbc2a07bfe37fc1044952b9

M  +8    -7    doc/kdesrc-buildrc/conf-options-table.docbook

https://invent.kde.org/sdk/kdesrc-build/-/commit/b638608f66252e84f507afb8cd56b7f7c65c05c2

diff --git a/doc/kdesrc-buildrc/conf-options-table.docbook b/doc/kdesrc-buildrc/conf-options-table.docbook
index c23c2c1b..e74858b1 100644
--- a/doc/kdesrc-buildrc/conf-options-table.docbook
+++ b/doc/kdesrc-buildrc/conf-options-table.docbook
@@ -695,10 +695,11 @@ on also use that proxy server, if possible, by setting the
 <member>Type</member><member>String</member>
 <member>Valid values</member><member><userinput>flat</userinput>,
 <userinput>invent</userinput>, <userinput>metadata</userinput></member>
+<member>Default value</member><member>flat</member>
 </simplelist>
 <para>This option is used to configure the layout which &kdesrc-build; should use when
 creating source and build directories.</para>
-<para>The <userinput>flat</userinput> layout is the default value, and will group all modules
+<para>The <userinput>flat</userinput> layout will group all modules
 directly underneath the top level source and build directories. For example,
 <literal>source/extragear/network/telepathy/ktp-text-ui</literal> in the <userinput>metadata</userinput>
 layout would be <literal>source/ktp-text-ui</literal> using the <userinput>flat</userinput> layout
@@ -727,19 +728,19 @@ due to changes in the project metadata.</para>
 <simplelist type='horiz' columns='2'>
 <member>Type</member><member>Boolean</member>
 <member>Default value</member><member>False</member>
-</simplelist>       
+</simplelist>
 
 <para>Module setting overrides global</para>
 
-<para>Set this option to <userinput>true</userinput> to make 
-&kdesrc-build; create VS Code project files (.vscode directory) in the module 
+<para>Set this option to <userinput>true</userinput> to make
+&kdesrc-build; create VS Code project files (.vscode directory) in the module
 source directory.</para>
 
-<para>The .vscode folder will be created in the project source directory, only 
-if it does not already exist. The configurations will enable the use of LSP, 
+<para>The .vscode folder will be created in the project source directory, only
+if it does not already exist. The configurations will enable the use of LSP,
 building, debugging, and running the project from within VS Code.</para>
 
-<para>The configuration also recommends extensions to install that are useful 
+<para>The configuration also recommends extensions to install that are useful
 for working on most KDE projects.</para>
 
 <para>You can also use the <link linkend="cmdline-generate-vscode-project-config">