[CORE] Add variable merge in `local.conf`

Added a function that unifies multiple assignments of a single variable
into a single assignment. For example:

```
VAR = "test"
VAR += "second-test
```
ends up with:
```
VAR += " \
   test \
   second-test \
"
```

Signed-off-by: Nicola Sparnacci <nicola.sparnacci@seco.com>

src/seco_setup_conf.py

@@ -383,6 +383,81 @@ def local_conf_normalize_structure(build_dir):
     with open(local_conf_path, 'w') as file:
         file.writelines(reordered_config)
 
+##
+# @brief Merges duplicate Yocto variable assignments in the local.conf file.
+#
+# This function reads the `local.conf` file, searches for all Yocto variables,
+# and merges all the values of the same variable into one line. It treats
+# `:append` as equivalent to `+=` and preserves the original order of variables
+# in the file. Lines that do not match the Yocto variable pattern are preserved
+# as is.
+#
+# @param build_dir Path to the build directory containing `conf/local.conf`.
+# @return None
+##
+def local_conf_merge_variables(build_dir):
+    local_conf_path = os.path.join(build_dir, "conf/local.conf")
+
+    with open(local_conf_path, "r") as file:
+        lines = file.readlines()
+
+    # Regex to match Yocto variable assignments, including `:append`
+    yocto_var_pattern = re.compile(r'^(\w+)(?::append)?\s*(\+?=)\s*"(.*)"')
+
+    # Process lines and collect variable assignments
+    output_lines = []
+    variables = {}
+    operators = {}
+    for line in lines:
+        match = yocto_var_pattern.match(line.strip())
+        if match:
+            var_name, operator, value = match.groups()
+            value = value.strip()
+            if var_name not in variables:
+                variables[var_name] = []
+                operators[var_name] = []
+                output_lines.append(line)
+
+            variables[var_name].append(value.replace("\"", ""))
+            # If `+=` or `:append` is used in ate least one assignment,
+            # ensure the final operator is `+=`
+            if ":append" in line:
+                operators[var_name].append("+=")
+            else:
+                operators[var_name].append(operator)
+        else:
+            # Preserve lines that do not match the regex
+            output_lines.append(line)
+
+    # Replace duplicate variables in the output lines
+    for lineidx, line in enumerate(output_lines):
+        match = yocto_var_pattern.match(line.strip())
+        if match:
+            var_name, _, _ = match.groups()
+            if var_name in variables:
+                # If the variable has multiple values, merge them into one line (removing empty 
+                # assignments)
+                if len(variables[var_name]) > 1:
+                    if all(op == "=" for op in operators[var_name]):
+                        operator = "="
+                        ssu.eprint(f"Warning: Found multiple '=' assignments for '{var_name}'. Merged but have a look at it.")
+                    else:
+                        operator = "+="
+                    
+                    merged_values = " \\\n".join(
+                        "    " + value for value in variables[var_name] if value.strip() != ""
+                    )  
+                    merged_line = var_name + " " + operator + ' " \\\n' + merged_values + ' \\\n"\n'
+                    output_lines[lineidx] = merged_line
+                else:
+                    output_lines[lineidx] = line
+                # Remove the variable after processing to avoid duplicates
+                del variables[var_name]
+
+    # Write the updated lines back to the file
+    with open(local_conf_path, "w") as file:
+        file.writelines(output_lines)
+
 ##
 # @brief Extracts the Seco's layers from a given bblayers.conf.
 #

src/seco_setup_environment.py

@@ -422,6 +422,10 @@ def environment_manager(args_cwd, args_build_dir, args_sdkmachine, reconfigure,
 
         # local.conf normalize structure (reorder sections)
         ssc.local_conf_normalize_structure(build_dir)
+        
+        # Merge multiple variable assignment into a single assignment
+        ssc.local_conf_merge_variables(build_dir)
+
     else:
         new_build_created = False
     

tests/test_seco_setup_conf.py

@@ -842,7 +842,123 @@ class TestBuildConfClass:
         # Assert the result matches the expected output
         assert result == expected_output
 
-    ##
+
+    ## 
+    # @brief Test merging of variable definitions in local.conf file.
+    #
+    # @param input_content The initial content of the `local.conf` file before processing.
+    # @param expected_content The expected content of the `local.conf` file after processing.
+    # @param expect_warning Boolean indicating whether a warning is expected to be emitted.
+    # @param tmp_path pytest fixture providing a temporary path for test file generation.
+    # This test suite validates the behavior of the `local_conf_merge_variables`
+    # function under various scenarios involving duplicate variable declarations
+    # in a Yocto local.conf file. The test cases cover:
+    # - No duplicates (no changes expected).
+    # - Duplicates with assignment (`=`), which should be merged into a multiline assignment.
+    # - Duplicates with `+=` (append), which should be consolidated properly.
+    ## 
+    @pytest.mark.parametrize(
+        "input_content, expected_content, expect_warning",
+        [
+            # Test case 1: No duplicates, no changes
+            (
+"""
+include SRCREV.conf
+
+TEST_VAR = "value1"
+SECOND_TEST_VAR = "value1"
+""",
+"""
+include SRCREV.conf
+
+TEST_VAR = "value1"
+SECOND_TEST_VAR = "value1"
+""",
+            False,
+            ),
+            # Test case 2: Duplicate variables with `=`
+            (
+"""
+include SRCREV.conf
+
+TEST_VAR = "value1"
+TEST_VAR = "value2"
+""",
+"""
+include SRCREV.conf
+
+TEST_VAR = " \\
+    value1 \\
+    value2 \\
+"
+""",
+            True,
+            ),
+            # Test case 3: Duplicate variables with `:append`
+            (
+"""
+include SRCREV.conf
+
+TEST_VAR = "value1"
+TEST_VAR += "value2"
+""",
+"""
+include SRCREV.conf
+
+TEST_VAR += " \\
+    value1 \\
+    value2 \\
+"
+""",
+            False,
+            ),
+            # Test case 4: Duplicate variables with `:append`
+            (
+"""
+include SRCREV.conf
+
+TEST_VAR = "value1"
+TEST_VAR += " "
+TEST_VAR += "value2"
+""",
+"""
+include SRCREV.conf
+
+TEST_VAR += " \\
+    value1 \\
+    value2 \\
+"
+""",
+            False,
+            ),
+        ],
+    )
+    def test_local_conf_merge_variables(self, input_content, expected_content, expect_warning, tmp_path):
+
+        # Create the temporary directory structure
+        build_dir = tmp_path / "build"
+        conf_dir = build_dir / "conf"
+        conf_dir.mkdir(parents=True)
+        conf_file = conf_dir / "local.conf"
+
+        # Create the local.conf file with sample content
+        conf_file.write_text(input_content)
+
+        # Call the function to test
+        with patch('seco_setup_utils.eprint') as mock_eprint:
+            ssc.local_conf_merge_variables(build_dir)
+
+            if (expect_warning):
+                mock_eprint.assert_called_once()
+
+        # Normalize both actual and expected content
+        result_content = conf_file.read_text()
+        normalized_result = result_content.strip()
+        normalized_expected = expected_content.strip()
+
+        # Assert that the normalized content matches
+        assert normalized_result == normalized_expected
+
     # @brief
     # Test the `local_conf_normalize_structure` function.
     #

tests/test_seco_setup_environment.py

@@ -310,13 +310,15 @@ class TestEnvClass:
             patch("seco_setup_conf.generate_srcrev_conf") as mock_generate_srcrev_conf, \
             patch("seco_setup_conf.local_conf_sanity_check") as mock_local_conf_sanity_check, \
             patch("seco_setup_conf.local_conf_normalize_structure") as mock_local_conf_normalize_structure, \
+            patch("seco_setup_conf.local_conf_merge_variables") as mock_local_conf_merge_variables, \
             patch("seco_setup_conf.print_welcome_message") as mock_print_welcome_message:
             yield (mock_get_cwd, mock_os_getcwd, mock_exists_build_dir, mock_set_sdkmachine, 
                 mock_setup_environment, mock_eprint, mock_run_get_config, 
                 mock_clusterize_config, mock_prepare_local_conf, 
                 mock_prepare_bblayers_conf, mock_customize_build, 
                 mock_generate_srcrev_conf, mock_local_conf_sanity_check,
-                mock_local_conf_normalize_structure, mock_print_welcome_message)
+                mock_local_conf_normalize_structure, mock_local_conf_merge_variables,
+                mock_print_welcome_message)
 
     ## @brief Test environment_manager with various scenarios.
     #
@@ -346,7 +348,8 @@ class TestEnvClass:
         mock_clusterize_config, mock_prepare_local_conf, 
         mock_prepare_bblayers_conf, mock_customize_build, 
         mock_generate_srcrev_conf, mock_local_conf_sanity_check,
-        mock_local_conf_normalize_structure, mock_print_welcome_message) = mock_environment_manager
+        mock_local_conf_normalize_structure, mock_local_conf_merge_variables,
+        mock_print_welcome_message) = mock_environment_manager
 
         # Mock behavior for tests
         pwd = "/some/current/dir"
@@ -384,6 +387,7 @@ class TestEnvClass:
                 mock_generate_srcrev_conf.assert_called_once()
                 mock_local_conf_sanity_check.assert_called_once()
                 mock_local_conf_normalize_structure.assert_called_once()
+                mock_local_conf_merge_variables.assert_called_once()
 
             if args_build_dir != None and reconfigure == False:
                 mock_print_welcome_message.assert_any_call(customize_build_result, None, None, None, None)