Fix(config): Allow duplicate keys in replication.config

Pass strict=False to configparser.ConfigParser() in get_config()
so that Gerrit's git-style multi-valued options parse cleanly.

Gerrit's pull-replication plugin writes one fetch refspec per
line under the [remote "..."] section, e.g.

    [remote "onap"]
      url = https://gerrit.onap.org/r/a/${name}.git
      fetch = +refs/heads/*:refs/heads/*
      fetch = +refs/tags/*:refs/tags/*
      fetch = +refs/changes/*:refs/changes/*

This is valid git config syntax for representing a list of
values for the same key.  Python's configparser defaults to
strict=True and refuses repeated keys, raising
DuplicateOptionError on the second 'fetch =' line.

A diagnostic capture from a CI deployment showed every hook
firing crash with that exception the moment find_and_dispatch()
called get_replication_remotes() -> get_config(REPLICATION),
dropping every patchset-created, comment-added and
change-merged event before any workflow dispatch could run.

g2p only reads the single-valued url, authgroup and
remotenamestyle keys from each remote, never the multi-valued
fetch key, so the 'last value wins' semantics that strict=False
introduces for duplicate keys have no functional impact on g2p.

Adds:

* tests/fixtures/replication_multi_fetch.config covering the
  pull-replication shape that triggered the field crash;
* test_get_config_tolerates_duplicate_keys asserting the parser
  loads the fixture without raising;
* test_get_replication_remotes_tolerates_duplicate_keys
  asserting the higher-level helper still produces the expected
  remotes mapping for that fixture.

Co-authored-by: Claude <claude@anthropic.com>
Change-Id: I692e6e15c5253d8d7493ad688ac9247e38af6b4d
Signed-off-by: Matthew Watkins <mwatkins@linuxfoundation.org>

Author: ModeSevenIndustrialSolutions

releasenotes/notes/configparser-strict-false-3e9f8a1b2c4d5061.yaml

@@ -0,0 +1,25 @@
+---
+fixes:
+  - |
+    Fix ``configparser.DuplicateOptionError`` raised from every hook
+    invocation when ``replication.config`` contains multi-valued
+    ``fetch = ...`` refspecs under a single ``[remote "..."]`` section.
+    This is the canonical shape Gerrit's pull-replication plugin
+    writes (and is valid git-config syntax for representing a list),
+    but Python's ``configparser`` defaults to ``strict=True`` and
+    refuses to parse repeated keys.  ``get_config()`` now constructs
+    the parser with ``strict=False``, which allows the multi-valued
+    keys through with "last value wins" semantics.  ``g2p`` only
+    reads the single-valued ``url``, ``authgroup`` and
+    ``remotenamestyle`` keys from the remote sections, never the
+    multi-valued ``fetch`` key, so the relaxed semantics have no
+    functional impact.
+upgrade:
+  - |
+    No operator action required.  Existing deployments that did not
+    trigger this crash (because their ``replication.config`` happened
+    to keep ``fetch`` to a single line per remote) see no behaviour
+    change.  Deployments that did crash after every hook event —
+    notably any pull-replication setup mirrored from a Gerrit source
+    — will start dispatching workflows successfully after this
+    release.

src/gerrit_to_platform/config.py

@@ -74,8 +74,23 @@ def get_config(config_type: str = DEFAULT_CONFIG) -> ConfigParser:
     Returns:
         ConfigParser: A loaded ConfigParser object with the requested
             configuration file
+
+    Notes:
+        ``replication.config`` follows git's config-file syntax, which
+        permits the same option key to repeat inside a section (the
+        canonical example is multiple ``fetch = ...`` refspecs under
+        one ``[remote "..."]``).  Python's ``configparser`` raises
+        ``DuplicateOptionError`` for that pattern unless ``strict`` is
+        false, so we disable the strict check here.  ``g2p`` only
+        reads ``url``, ``authgroup`` and ``remotenamestyle`` from the
+        remote sections, never the multi-valued ``fetch`` key, so the
+        "last value wins" semantics that ``strict=False`` introduces
+        for duplicates have no functional impact.  The same parser is
+        used for ``gerrit_to_platform.ini`` for consistency; that
+        file is operator-controlled and does not contain duplicate
+        keys in practice.
     """
-    config = configparser.ConfigParser()
+    config = configparser.ConfigParser(strict=False)
     conf_file = CONFIG_FILES[config_type]
     with open(conf_file) as config_file:
         config.read_file(config_file, conf_file)

tests/fixtures/replication_multi_fetch.config

@@ -0,0 +1,33 @@
+# Pull-replication configuration with multi-valued fetch refspecs.
+# Mirrors the shape Gerrit's pull-replication plugin emits in the
+# field; configparser raises DuplicateOptionError on this without
+# strict=False.
+
+[gerrit]
+  replicateOnStartup = true
+  autoReload = true
+
+[replication]
+  lockErrorMaxRetries = 5
+  maxRetries = 5
+  useCGitClient = false
+  refsBatchSize = 50
+
+[remote "onap"]
+  url = https://gerrit.onap.org/r/a/${name}.git
+  fetchEvery = 60s
+  timeout = 600
+  connectionTimeout = 600000
+  replicationDelay = 0
+  replicationRetry = 60
+  threads = 4
+  createMissingRepositories = true
+  replicateHiddenProjects = false
+  fetch = +refs/heads/*:refs/heads/*
+  fetch = +refs/tags/*:refs/tags/*
+  fetch = +refs/changes/*:refs/changes/*
+
+[remote "github-g2p"]
+  url = git@github.com:modeseven-gerrit-onap/${name}.git
+  authGroup = GitHub Replication
+  remoteNameStyle = dash

tests/test_config.py

@@ -32,6 +32,9 @@
 
 TEST_CONFIG = os.path.join(FIXTURE_DIR, "testconfig.ini")
 REPLICATION_CONFIG = os.path.join(FIXTURE_DIR, "replication.config")
+REPLICATION_MULTI_FETCH_CONFIG = os.path.join(
+    FIXTURE_DIR, "replication_multi_fetch.config"
+)
 
 MOCK_CONFIG_FILES = {
     CONFIG: TEST_CONFIG,
@@ -50,6 +53,56 @@ def test_get_config(mocker):
     assert get_config(REPLICATION).has_section('remote "github"')
 
 
+def test_get_config_tolerates_duplicate_keys(mocker):
+    """Multi-valued ``fetch`` refspecs in replication.config must parse.
+
+    Gerrit's pull-replication plugin writes multiple ``fetch = ...``
+    lines under a single ``[remote "..."]`` section (valid git config
+    syntax for representing a list).  Python's ``configparser`` defaults
+    to ``strict=True`` and raises ``DuplicateOptionError`` for that
+    pattern, which previously crashed every g2p hook the moment
+    ``find_and_dispatch`` called ``get_replication_remotes()``.  This
+    test loads such a config and asserts it parses without raising.
+    """
+    mocker.patch.object(
+        gerrit_to_platform.config,
+        "CONFIG_FILES",
+        {
+            CONFIG: TEST_CONFIG,
+            REPLICATION: REPLICATION_MULTI_FETCH_CONFIG,
+        },
+    )
+    config = get_config(REPLICATION)
+    assert config.has_section('remote "onap"')
+    # ``strict=False`` keeps the last value when keys repeat; verify
+    # the URL field (which is single-valued) survives intact, and the
+    # multi-valued ``fetch`` field at least returns a string rather
+    # than raising.
+    assert config.get('remote "onap"', "url") == (
+        "https://gerrit.onap.org/r/a/${name}.git"
+    )
+    assert config.has_option('remote "onap"', "fetch")
+
+
+def test_get_replication_remotes_tolerates_duplicate_keys(mocker):
+    """``get_replication_remotes`` must succeed against a multi-fetch
+    replication.config (regression for the field-observed crash).
+    """
+    mocker.patch.object(
+        gerrit_to_platform.config,
+        "CONFIG_FILES",
+        {
+            CONFIG: TEST_CONFIG,
+            REPLICATION: REPLICATION_MULTI_FETCH_CONFIG,
+        },
+    )
+    remotes = get_replication_remotes()
+    assert "github" in remotes
+    assert "github-g2p" in remotes["github"]
+    assert remotes["github"]["github-g2p"]["owner"] == ("modeseven-gerrit-onap")
+    assert remotes["github"]["github-g2p"]["remotenamestyle"] == "dash"
+
+
 def test_get_mapping(mocker):
     """Test get_mapping"""
     mocker.patch.object(