From 85e4ee5b54c334d4104e6c3b2f3fda11cd9b2dd6 Mon Sep 17 00:00:00 2001
From: Xavier Claessens <xavier.claessens@collabora.com>
Date: Sat, 21 Oct 2023 09:47:39 -0400
Subject: [PATCH] File: Add full_path() method

This is needed now that str.format() is not allowing it any more. It is
also more consistent with other objects that have that method as well,
such as build targets.

Fixes: #12406
---
 docs/markdown/snippets/file-full-path.md     |  7 +++++++
 docs/yaml/objects/file.yaml                  | 12 +++++++++++-
 mesonbuild/interpreter/interpreterobjects.py | 11 ++++++++++-
 test cases/common/74 file object/meson.build |  6 ++++++
 4 files changed, 34 insertions(+), 2 deletions(-)
 create mode 100644 docs/markdown/snippets/file-full-path.md

diff --git a/docs/markdown/snippets/file-full-path.md b/docs/markdown/snippets/file-full-path.md
new file mode 100644
index 000000000..fbb8e548d
--- /dev/null
+++ b/docs/markdown/snippets/file-full-path.md
@@ -0,0 +1,7 @@
+## File object now has `full_path()` method
+
+Returns a full path pointing to the file. This is useful for printing the path
+with e.g [[message]] function for debugging purpose.
+
+**NOTE:** In most cases using the object itself will do the same job
+as this and will also allow Meson to setup dependencies correctly.
diff --git a/docs/yaml/objects/file.yaml b/docs/yaml/objects/file.yaml
index 6aa0b85ce..5d2ad3053 100644
--- a/docs/yaml/objects/file.yaml
+++ b/docs/yaml/objects/file.yaml
@@ -1,3 +1,13 @@
 name: file
 long_name: File
-description: Opaque object that stores the path to an existing file
+description: Object that stores the path to an existing file
+
+methods:
+- name: full_path
+  returns: str
+  since: 1.4.0
+  description: |
+    Returns a full path pointing to the file. This is useful for printing the
+    path with e.g [[message]] function for debugging purpose.
+    **NOTE:** In most cases using the object itself will do the same job
+    as this and will also allow Meson to setup dependencies correctly.
diff --git a/mesonbuild/interpreter/interpreterobjects.py b/mesonbuild/interpreter/interpreterobjects.py
index f13e3ff4a..4320cf52e 100644
--- a/mesonbuild/interpreter/interpreterobjects.py
+++ b/mesonbuild/interpreter/interpreterobjects.py
@@ -701,7 +701,16 @@ class IncludeDirsHolder(ObjectHolder[build.IncludeDirs]):
     pass
 
 class FileHolder(ObjectHolder[mesonlib.File]):
-    pass
+    def __init__(self, file: mesonlib.File, interpreter: 'Interpreter'):
+        super().__init__(file, interpreter)
+        self.methods.update({'full_path': self.full_path_method,
+                             })
+
+    @noPosargs
+    @noKwargs
+    @FeatureNew('file.full_path', '1.4.0')
+    def full_path_method(self, args: T.List[TYPE_var], kwargs: TYPE_kwargs) -> str:
+        return self.held_object.absolute_path(self.env.source_dir, self.env.build_dir)
 
 class HeadersHolder(ObjectHolder[build.Headers]):
     pass
diff --git a/test cases/common/74 file object/meson.build b/test cases/common/74 file object/meson.build
index fc01bfec7..05c24aef8 100644
--- a/test cases/common/74 file object/meson.build	
+++ b/test cases/common/74 file object/meson.build	
@@ -6,3 +6,9 @@ test('fobj', executable('fobj', prog0, lib0))
 
 subdir('subdir1')
 subdir('subdir2')
+
+# Use fs.as_posix() because / operator replaces \ with / in the path, but
+# full_path() method is not doing that. This is a pretty inconsistent across all
+# Meson APIs.
+fs = import('fs')
+assert(fs.as_posix(prog0[0].full_path()) == fs.as_posix(meson.current_source_dir() / 'prog.c'))