fix: don't modify 'prefix' for relocatable pkg-config files (#5157)

A relocatable `.pc` file has a `prefix` key beginning with
`${pcfiledir}`. The `prefix` key is not modified if the `.pc`
file is relocatable.

Co-authored-by: Callahan <[email protected]>

requirements-devel.txt

@@ -59,7 +59,7 @@ craft-grammar==2.0.1
     # via
     #   craft-application
     #   snapcraft (setup.py)
-craft-parts==2.3.0
+craft-parts==2.4.1
     # via
     #   craft-application
     #   snapcraft (setup.py)

requirements-docs.txt

@@ -73,7 +73,7 @@ craft-grammar==2.0.1
     # via
     #   craft-application
     #   snapcraft (setup.py)
-craft-parts==2.3.0
+craft-parts==2.4.1
     # via
     #   craft-application
     #   snapcraft (setup.py)

requirements.txt

@@ -41,7 +41,7 @@ craft-grammar==2.0.1
     # via
     #   craft-application
     #   snapcraft (setup.py)
-craft-parts==2.3.0
+craft-parts==2.4.1
     # via
     #   craft-application
     #   snapcraft (setup.py)

setup.py

@@ -102,7 +102,7 @@ def recursive_data_files(directory, install_directory):
     "craft-archives~=2.0",
     "craft-cli>=2.15.0",
     "craft-grammar>=2.0.1,<3.0.0",
-    "craft-parts==2.3.0",
+    "craft-parts==2.4.1",
     "craft-platforms~=0.4",
     "craft-providers>=2.0.4,<3.0.0",
     "craft-store>=3.0.2,<4.0.0",

snapcraft_legacy/internal/repo/_base.py

@@ -346,6 +346,10 @@ def fix_pkg_config(
     - From snaps built locally: `<local-path-to-project>/stage`
     - Built during the build stage: the install directory
 
+    But if the prefix begins with `pcfiledir` variable, it must be kept as-is,
+    because that variable refers to the current location of the .pc file. It
+    allows to create "relocatable" pkgconfig files, so no changes are required.
+
     :param pkg_config_file: pkg-config (.pc) file to modify
     :param prefix_prepend: directory to prepend to the prefix
     :param prefix_trim: directory to remove from prefix
@@ -358,10 +362,17 @@ def fix_pkg_config(
         f"^prefix=(?P<trim>{'|'.join(prefixes_to_trim)})(?P<prefix>.*)"
     )
     pattern = re.compile("^prefix=(?P<prefix>.*)")
+    pattern_pcfiledir = re.compile("^prefix *= *[$]{pcfiledir}.*")
 
     # process .pc file
     with fileinput.input(pkg_config_file, inplace=True) as input_file:
         for line in input_file:
+            # If the prefix begins with ${pcfiledir} statement, this is
+            # a position-independent (thus, "relocatable") .pc file, so
+            # no changes are required.
+            if pattern_pcfiledir.search(line) is not None:
+                print(line, end="")
+                continue
             match = pattern.search(line)
             match_trim = pattern_trim.search(line)
 

tests/legacy/unit/repo/test_base.py

@@ -369,6 +369,22 @@ def test_fix_pkg_config_trim_prefix(
     )
 
 
+def test_fix_pkg_config_with_pcfiledir(
+    tmpdir,
+    pkg_config_file,
+    expected_pkg_config_content,
+):
+    """Verify prefixes that begin with ${pcfiledir} aren't modified."""
+    pc_file = tmpdir / "my-file.pc"
+    pkg_config_file(pc_file, "${pcfiledir}/../../..")
+
+    fix_pkg_config(tmpdir, pc_file)
+
+    assert pc_file.read_text(encoding="utf-8") == expected_pkg_config_content(
+        "${pcfiledir}/../../.."
+    )
+
+
 def test_normalize_fix_pkg_config(tmpdir, pkg_config_file, expected_pkg_config_content):
     """Verify normalization fixes pkg-config files."""
     pc_file = tmpdir / "my-file.pc"