hawdb_core/
error.rs

1// Copyright 2026 Nowledge
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15use crate::RuntimeCapability;
16use std::fmt::{Display, Formatter};
17
18mod resource;
19pub use resource::{ResourceBudgetError, ResourceBudgetKind, ResourceBudgetScope};
20
21/// Descriptor admission failures are distinct from corrupt storage or a busy
22/// branch. Project quota counts belong to one engine resource domain; OS-limit
23/// failures can additionally report the process allowance when it is known.
24#[derive(Debug, Clone, PartialEq, Eq)]
25pub enum FileDescriptorError {
26    InvalidBudget {
27        limit: usize,
28    },
29    ConfigurationConflict {
30        configured: usize,
31        requested: usize,
32    },
33    BudgetExceeded {
34        requested: usize,
35        available: usize,
36        limit: usize,
37    },
38    OsLimit {
39        requested: usize,
40        os_code: Option<i32>,
41        soft: Option<u64>,
42        hard: Option<u64>,
43    },
44}
45
46impl Display for FileDescriptorError {
47    fn fmt(&self, formatter: &mut Formatter<'_>) -> std::fmt::Result {
48        match self {
49            Self::InvalidBudget { limit } => write!(formatter, "invalid file descriptor budget: {limit}"),
50            Self::ConfigurationConflict { configured, requested } => write!(formatter,
51                "project file descriptor budget conflict: configured {configured}, requested {requested}"),
52            Self::BudgetExceeded { requested, available, limit } => write!(formatter,
53                "project file descriptor budget exceeded: requested {requested}, available {available}, limit {limit}"),
54            Self::OsLimit { requested, os_code, soft, hard } => write!(formatter,
55                "operating system file descriptor limit: requested {requested}, soft {soft:?}, hard {hard:?}, OS code {os_code:?}"),
56        }
57    }
58}
59
60impl std::error::Error for FileDescriptorError {}
61
62/// The result resource whose selected read limit rejected delivery.
63#[derive(Debug, Clone, Copy, PartialEq, Eq)]
64pub enum ReadBudgetResource {
65    Rows,
66    PayloadBytes,
67}
68
69/// Retains budget identity independently of the execution diagnostic text.
70#[derive(Debug, Clone, PartialEq, Eq)]
71pub struct ReadBudgetError {
72    pub resource: ReadBudgetResource,
73    pub limit: usize,
74    pub message: String,
75}
76
77impl Display for ReadBudgetError {
78    fn fmt(&self, formatter: &mut Formatter<'_>) -> std::fmt::Result {
79        formatter.write_str(&self.message)
80    }
81}
82
83impl std::error::Error for ReadBudgetError {}
84
85#[derive(Debug, Clone, PartialEq, Eq)]
86pub enum HawDBError {
87    Parse(String),
88    Semantic(String),
89    Storage(String),
90    FileDescriptors(FileDescriptorError),
91    StorageIntegrity(String),
92    Execution(String),
93    /// Box the diagnostic so successful Result values do not grow with its fields.
94    ResourceBudgetExceeded(Box<ResourceBudgetError>),
95    ReadBudgetExceeded(ReadBudgetError),
96    GraphExpansionCandidateLimitExceeded {
97        requested: usize,
98        limit: usize,
99    },
100    GraphExpansionPayloadLimitExceeded {
101        requested: usize,
102        limit: usize,
103    },
104    TransactionConflict {
105        read_epoch: u64,
106        committed_epoch: u64,
107        key: String,
108    },
109    AppendSequenceExhausted {
110        table: String,
111        watermark: i64,
112        requested: usize,
113    },
114    CapabilityUnavailable {
115        capability: RuntimeCapability,
116    },
117    BranchCommandUnsupported {
118        command: &'static str,
119        context: &'static str,
120    },
121    BranchBusy {
122        resource: &'static str,
123    },
124    BranchEvidenceBudgetExceeded {
125        resource: &'static str,
126        requested: u64,
127        limit: u64,
128    },
129    /// An unleased pending create prevents a complete reclamation mark.
130    /// This identifies retained evidence, not authorization to discard it.
131    BranchReclamationBlocked {
132        branch_id: crate::Uuid,
133        catalog_revision: u64,
134        metadata_revision: u64,
135        cause: Box<HawDBError>,
136    },
137}
138
139impl Display for HawDBError {
140    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
141        match self {
142            HawDBError::Parse(message) => write!(f, "parse error: {message}"),
143            HawDBError::Semantic(message) => write!(f, "semantic error: {message}"),
144            HawDBError::Storage(message) => write!(f, "storage error: {message}"),
145            HawDBError::FileDescriptors(error) => Display::fmt(error, f),
146            HawDBError::StorageIntegrity(message) => {
147                write!(f, "storage integrity error: {message}")
148            }
149            HawDBError::Execution(message) => write!(f, "execution error: {message}"),
150            HawDBError::ResourceBudgetExceeded(error) => write!(f, "execution error: {error}"),
151            HawDBError::ReadBudgetExceeded(error) => write!(f, "execution error: {error}"),
152            HawDBError::GraphExpansionCandidateLimitExceeded { requested, limit } => write!(
153                f,
154                "graph expansion candidate_limit exceeded: requested {requested} rows, limit {limit} rows; configure ExecutionMemoryConfig.graph_expansion_budget.candidate_limit"
155            ),
156            HawDBError::GraphExpansionPayloadLimitExceeded { requested, limit } => write!(
157                f,
158                "graph expansion payload_byte_limit exceeded: requested {requested} bytes, limit {limit} bytes; configure ExecutionMemoryConfig.graph_expansion_budget.payload_byte_limit"
159            ),
160            HawDBError::TransactionConflict {
161                read_epoch,
162                committed_epoch,
163                key,
164            } => write!(
165                f,
166                "transaction conflict on {key}: transaction read epoch {read_epoch}, conflicting commit epoch {committed_epoch}"
167            ),
168            HawDBError::AppendSequenceExhausted {
169                table,
170                watermark,
171                requested,
172            } => write!(
173                f,
174                "append commit sequence exhausted for table {table}: watermark={watermark}, requested={requested}"
175            ),
176            HawDBError::CapabilityUnavailable { capability } => {
177                write!(f, "capability unavailable: {}", capability.as_str())
178            }
179            HawDBError::BranchCommandUnsupported { command, context } => {
180                write!(f, "{command} is unavailable in {context}")
181            }
182            HawDBError::BranchBusy { resource } => write!(f, "branch is busy: {resource}"),
183            HawDBError::BranchEvidenceBudgetExceeded { resource, requested, limit } => write!(
184                f,
185                "branch quarantine evidence {resource} budget exceeded: requested {requested}, limit {limit}"
186            ),
187            HawDBError::BranchReclamationBlocked {
188                branch_id,
189                catalog_revision,
190                metadata_revision,
191                cause,
192            } => write!(
193                f,
194                "pending branch {branch_id} blocks reclamation at catalog revision {catalog_revision}, branch revision {metadata_revision}: {cause}"
195            ),
196        }
197    }
198}
199
200impl std::error::Error for HawDBError {
201    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
202        match self {
203            Self::FileDescriptors(error) => Some(error),
204            Self::ResourceBudgetExceeded(error) => Some(error.as_ref()),
205            Self::ReadBudgetExceeded(error) => Some(error),
206            Self::BranchReclamationBlocked { cause, .. } => Some(cause.as_ref()),
207            _ => None,
208        }
209    }
210}
211
212impl HawDBError {
213    pub fn read_budget_exceeded(
214        resource: ReadBudgetResource,
215        limit: usize,
216        message: impl Into<String>,
217    ) -> Self {
218        Self::ReadBudgetExceeded(ReadBudgetError {
219            resource,
220            limit,
221            message: message.into(),
222        })
223    }
224
225    /// Preserve a resource rejection through nested storage error wrappers.
226    pub fn from_storage_error(error: impl std::error::Error + 'static) -> Self {
227        if let Some(error) = (&error as &dyn std::error::Error).downcast_ref::<Self>() {
228            return error.clone();
229        }
230        if let Some(resource) = file_descriptor_error(&error) {
231            Self::FileDescriptors(resource)
232        } else if let Some(resource) = resource::find_resource_budget_error(&error) {
233            Self::from(resource)
234        } else {
235            Self::Storage(error.to_string())
236        }
237    }
238
239    /// `from_storage_error`, prefixing a generic `Storage` message with
240    /// `context` and leaving a preserved typed cause (e.g. `FileDescriptors`)
241    /// unprefixed and unchanged.
242    pub fn from_storage_error_with_context(
243        error: impl std::error::Error + 'static,
244        context: &str,
245    ) -> Self {
246        match Self::from_storage_error(error) {
247            Self::Storage(message) => Self::Storage(format!("{context}: {message}")),
248            error => error,
249        }
250    }
251
252    pub const fn is_retryable_transaction_conflict(&self) -> bool {
253        matches!(self, Self::TransactionConflict { .. })
254    }
255}
256
257pub type Result<T> = std::result::Result<T, HawDBError>;
258
259impl From<ResourceBudgetError> for HawDBError {
260    fn from(error: ResourceBudgetError) -> Self {
261        Self::ResourceBudgetExceeded(Box::new(error))
262    }
263}
264
265impl From<std::io::Error> for HawDBError {
266    fn from(error: std::io::Error) -> Self {
267        Self::from_storage_error(error)
268    }
269}
270
271pub fn file_descriptor_error(
272    error: &(dyn std::error::Error + 'static),
273) -> Option<FileDescriptorError> {
274    let mut current = Some(error);
275    while let Some(error) = current {
276        if let Some(resource) = error.downcast_ref::<FileDescriptorError>() {
277            return Some(resource.clone());
278        }
279        if let Some(HawDBError::FileDescriptors(resource)) = error.downcast_ref::<HawDBError>() {
280            return Some(resource.clone());
281        }
282        if let Some(error) = error.downcast_ref::<std::io::Error>() {
283            if let Some(code) = error.raw_os_error()
284                && descriptor_os_limit(code)
285            {
286                return Some(FileDescriptorError::OsLimit {
287                    requested: 1,
288                    os_code: Some(code),
289                    soft: None,
290                    hard: None,
291                });
292            }
293            // io::Error::source can skip its boxed concrete error. Inspect it
294            // explicitly so typed capacity rejections survive each IO layer.
295            if let Some(inner) = error.get_ref()
296                && let Some(resource) = file_descriptor_error(inner)
297            {
298                return Some(resource);
299            }
300        }
301        current = error.source();
302    }
303    None
304}
305
306fn descriptor_os_limit(code: i32) -> bool {
307    #[cfg(unix)]
308    {
309        matches!(code, 23 | 24)
310    }
311    #[cfg(windows)]
312    {
313        code == 4
314    }
315    #[cfg(not(any(unix, windows)))]
316    {
317        let _ = code;
318        false
319    }
320}
hawdb_core/error.rs

hawdb_core/
error.rs
