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{
    "id": 21287,
    "url": "https://patchwork.libcamera.org/api/patches/21287/?format=api",
    "web_url": "https://patchwork.libcamera.org/patch/21287/",
    "project": {
        "id": 1,
        "url": "https://patchwork.libcamera.org/api/projects/1/?format=api",
        "name": "libcamera",
        "link_name": "libcamera",
        "list_id": "libcamera_core",
        "list_email": "libcamera-devel@lists.libcamera.org",
        "web_url": "",
        "scm_url": "",
        "webscm_url": ""
    },
    "msgid": "<20240916222834.464460-1-stefan.klug@ideasonboard.com>",
    "date": "2024-09-16T22:28:20",
    "name": "libcamera: yaml-parser: Differentiate between empty and empty string",
    "commit_ref": null,
    "pull_url": null,
    "state": "accepted",
    "archived": false,
    "hash": "ab25d6e4bdd6d22649c639acf01123e675cdd84b",
    "submitter": {
        "id": 184,
        "url": "https://patchwork.libcamera.org/api/people/184/?format=api",
        "name": "Stefan Klug",
        "email": "stefan.klug@ideasonboard.com"
    },
    "delegate": null,
    "mbox": "https://patchwork.libcamera.org/patch/21287/mbox/",
    "series": [
        {
            "id": 4604,
            "url": "https://patchwork.libcamera.org/api/series/4604/?format=api",
            "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=4604",
            "date": "2024-09-16T22:28:20",
            "name": "libcamera: yaml-parser: Differentiate between empty and empty string",
            "version": 1,
            "mbox": "https://patchwork.libcamera.org/series/4604/mbox/"
        }
    ],
    "comments": "https://patchwork.libcamera.org/api/patches/21287/comments/",
    "check": "pending",
    "checks": "https://patchwork.libcamera.org/api/patches/21287/checks/",
    "tags": {},
    "headers": {
        "Return-Path": "<libcamera-devel-bounces@lists.libcamera.org>",
        "X-Original-To": "parsemail@patchwork.libcamera.org",
        "Delivered-To": "parsemail@patchwork.libcamera.org",
        "Received": [
            "from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 9060BC324C\n\tfor <parsemail@patchwork.libcamera.org>;\n\tMon, 16 Sep 2024 22:28:55 +0000 (UTC)",
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        ],
        "Authentication-Results": "lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"FFZUiTzj\"; dkim-atps=neutral",
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        "From": "Stefan Klug <stefan.klug@ideasonboard.com>",
        "To": "libcamera-devel@lists.libcamera.org",
        "Cc": "Stefan Klug <stefan.klug@ideasonboard.com>",
        "Subject": "[PATCH] libcamera: yaml-parser: Differentiate between empty and\n\tempty string",
        "Date": "Tue, 17 Sep 2024 00:28:20 +0200",
        "Message-ID": "<20240916222834.464460-1-stefan.klug@ideasonboard.com>",
        "X-Mailer": "git-send-email 2.43.0",
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        "Content-Transfer-Encoding": "8bit",
        "X-BeenThere": "libcamera-devel@lists.libcamera.org",
        "X-Mailman-Version": "2.1.29",
        "Precedence": "list",
        "List-Id": "<libcamera-devel.lists.libcamera.org>",
        "List-Unsubscribe": "<https://lists.libcamera.org/options/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=unsubscribe>",
        "List-Archive": "<https://lists.libcamera.org/pipermail/libcamera-devel/>",
        "List-Post": "<mailto:libcamera-devel@lists.libcamera.org>",
        "List-Help": "<mailto:libcamera-devel-request@lists.libcamera.org?subject=help>",
        "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>",
        "Errors-To": "libcamera-devel-bounces@lists.libcamera.org",
        "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>"
    },
    "content": "When accessing a nonexistent key on a dict the YamlObject returns an\nempty element. This element can happily be casted to a string which is\nunexpected. For example the following statement:\nyamlDict[\"nonexistant\"].get<string>(\"default\") is expected to return\n\"default\" but actually returns \"\". Fix this by introducing a empty type\nto distinguish between an empty YamlObject and a YamlObject of type\nvalue containing an empty string. For completeness add an isEmpty()\nfunction to be able to test for that type.\n\nSigned-off-by: Stefan Klug <stefan.klug@ideasonboard.com>\n---\n include/libcamera/internal/yaml_parser.h |  5 +++++\n src/libcamera/yaml_parser.cpp            | 20 ++++++++++++++------\n test/yaml-parser.cpp                     |  6 ++++++\n 3 files changed, 25 insertions(+), 6 deletions(-)",
    "diff": "diff --git a/include/libcamera/internal/yaml_parser.h b/include/libcamera/internal/yaml_parser.h\nindex 16708e488d88..33c3a96fed47 100644\n--- a/include/libcamera/internal/yaml_parser.h\n+++ b/include/libcamera/internal/yaml_parser.h\n@@ -159,6 +159,10 @@ public:\n \t{\n \t\treturn type_ == Type::Dictionary;\n \t}\n+\tbool isEmpty() const\n+\t{\n+\t\treturn type_ == Type::Empty;\n+\t}\n \n \tstd::size_t size() const;\n \n@@ -212,6 +216,7 @@ private:\n \t\tDictionary,\n \t\tList,\n \t\tValue,\n+\t\tEmpty,\n \t};\n \n \ttemplate<typename T>\ndiff --git a/src/libcamera/yaml_parser.cpp b/src/libcamera/yaml_parser.cpp\nindex 8b6a403898be..eb72529136f7 100644\n--- a/src/libcamera/yaml_parser.cpp\n+++ b/src/libcamera/yaml_parser.cpp\n@@ -38,12 +38,12 @@ static const YamlObject empty;\n  * \\brief A class representing the tree structure of the YAML content\n  *\n  * The YamlObject class represents the tree structure of YAML content. A\n- * YamlObject can be a dictionary or list of YamlObjects or a value if a tree\n- * leaf.\n+ * YamlObject can be empty, a dictionary or list of YamlObjects or a value if a\n+ * tree leaf.\n  */\n \n YamlObject::YamlObject()\n-\t: type_(Type::Value)\n+\t: type_(Type::Empty)\n {\n }\n \n@@ -70,6 +70,13 @@ YamlObject::~YamlObject() = default;\n  * \\return True if the YamlObject is a dictionary, false otherwise\n  */\n \n+/**\n+ * \\fn YamlObject::isEmpty()\n+ * \\brief Return whether the YamlObject is a empty\n+ *\n+ * \\return True if the YamlObject is empty, false otherwise\n+ */\n+\n /**\n  * \\fn YamlObject::size()\n  * \\brief Retrieve the number of elements in a dictionary or list YamlObject\n@@ -443,7 +450,8 @@ template std::optional<std::vector<Size>> YamlObject::getList<Size>() const;\n  *\n  * This function retrieves an element of the YamlObject. Only YamlObject\n  * instances of List type associate elements with index, calling this function\n- * on other types of instances is invalid and results in undefined behaviour.\n+ * on other types of instances or with an invalid index results in an empty\n+ * object.\n  *\n  * \\return The YamlObject as an element of the list\n  */\n@@ -480,8 +488,8 @@ bool YamlObject::contains(const std::string &key) const\n  *\n  * This function retrieve a member of a YamlObject by name. Only YamlObject\n  * instances of Dictionary type associate elements with names, calling this\n- * function on other types of instances is invalid and results in undefined\n- * behaviour.\n+ * function on other types of instances or with a non existant key results in an\n+ * empty object.\n  *\n  * \\return The YamlObject corresponding to the \\a key member\n  */\ndiff --git a/test/yaml-parser.cpp b/test/yaml-parser.cpp\nindex 81c829834667..b8ae0b4c11f8 100644\n--- a/test/yaml-parser.cpp\n+++ b/test/yaml-parser.cpp\n@@ -514,6 +514,12 @@ protected:\n \t\t\ti++;\n \t\t}\n \n+\t\t/* Test access to nonexistent member */\n+\t\tif (dictObj[\"nonexistent\"].get<std::string>(\"default\") != \"default\") {\n+\t\t\tcerr << \"Accessing nonexistent dict fails to return default\" << std::endl;\n+\t\t\treturn TestFail;\n+\t\t}\n+\n \t\t/* Make sure utils::map_keys() works on the adapter. */\n \t\t(void)utils::map_keys(dictObj.asDict());\n \n",
    "prefixes": []
}