ruma_common/api/
metadata.rs

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
use std::{
    cmp::Ordering,
    fmt::{self, Display, Write},
    str::FromStr,
};

use bytes::BufMut;
use http::{
    header::{self, HeaderName, HeaderValue},
    Method,
};
use percent_encoding::utf8_percent_encode;
use tracing::warn;

use super::{
    error::{IntoHttpError, UnknownVersionError},
    AuthScheme, SendAccessToken,
};
use crate::{percent_encode::PATH_PERCENT_ENCODE_SET, serde::slice_to_buf, RoomVersionId};

/// Metadata about an API endpoint.
#[derive(Clone, Debug, PartialEq, Eq)]
#[allow(clippy::exhaustive_structs)]
pub struct Metadata {
    /// The HTTP method used by this endpoint.
    pub method: Method,

    /// Whether or not this endpoint is rate limited by the server.
    pub rate_limited: bool,

    /// What authentication scheme the server uses for this endpoint.
    pub authentication: AuthScheme,

    /// All info pertaining to an endpoint's (historic) paths, deprecation version, and removal.
    pub history: VersionHistory,
}

impl Metadata {
    /// Returns an empty request body for this Matrix request.
    ///
    /// For `GET` requests, it returns an entirely empty buffer, for others it returns an empty JSON
    /// object (`{}`).
    pub fn empty_request_body<B>(&self) -> B
    where
        B: Default + BufMut,
    {
        if self.method == Method::GET {
            Default::default()
        } else {
            slice_to_buf(b"{}")
        }
    }

    /// Transform the `SendAccessToken` into an access token if the endpoint requires it, or if it
    /// is `SendAccessToken::Force`.
    ///
    /// Fails if the endpoint requires an access token but the parameter is `SendAccessToken::None`,
    /// or if the access token can't be converted to a [`HeaderValue`].
    pub fn authorization_header(
        &self,
        access_token: SendAccessToken<'_>,
    ) -> Result<Option<(HeaderName, HeaderValue)>, IntoHttpError> {
        Ok(match self.authentication {
            AuthScheme::None => match access_token.get_not_required_for_endpoint() {
                Some(token) => Some((header::AUTHORIZATION, format!("Bearer {token}").try_into()?)),
                None => None,
            },

            AuthScheme::AccessToken => {
                let token = access_token
                    .get_required_for_endpoint()
                    .ok_or(IntoHttpError::NeedsAuthentication)?;

                Some((header::AUTHORIZATION, format!("Bearer {token}").try_into()?))
            }

            AuthScheme::AccessTokenOptional => match access_token.get_required_for_endpoint() {
                Some(token) => Some((header::AUTHORIZATION, format!("Bearer {token}").try_into()?)),
                None => None,
            },

            AuthScheme::AppserviceToken => match access_token.get_required_for_appservice() {
                Some(token) => Some((header::AUTHORIZATION, format!("Bearer {token}").try_into()?)),
                None => None,
            },

            AuthScheme::ServerSignatures => None,
        })
    }

    /// Generate the endpoint URL for this endpoint.
    pub fn make_endpoint_url(
        &self,
        versions: &[MatrixVersion],
        base_url: &str,
        path_args: &[&dyn Display],
        query_string: &str,
    ) -> Result<String, IntoHttpError> {
        let path_with_placeholders = self.history.select_path(versions)?;

        let mut res = base_url.strip_suffix('/').unwrap_or(base_url).to_owned();
        let mut segments = path_with_placeholders.split('/');
        let mut path_args = path_args.iter();

        let first_segment = segments.next().expect("split iterator is never empty");
        assert!(first_segment.is_empty(), "endpoint paths must start with '/'");

        for segment in segments {
            if segment.starts_with(':') {
                let arg = path_args
                    .next()
                    .expect("number of placeholders must match number of arguments")
                    .to_string();
                let arg = utf8_percent_encode(&arg, PATH_PERCENT_ENCODE_SET);

                write!(res, "/{arg}").expect("writing to a String using fmt::Write can't fail");
            } else {
                res.reserve(segment.len() + 1);
                res.push('/');
                res.push_str(segment);
            }
        }

        if !query_string.is_empty() {
            res.push('?');
            res.push_str(query_string);
        }

        Ok(res)
    }

    // Used for generated `#[test]`s
    #[doc(hidden)]
    pub fn _path_parameters(&self) -> Vec<&'static str> {
        let path = self.history.all_paths().next().unwrap();
        path.split('/').filter_map(|segment| segment.strip_prefix(':')).collect()
    }
}

/// The complete history of this endpoint as far as Ruma knows, together with all variants on
/// versions stable and unstable.
///
/// The amount and positioning of path variables are the same over all path variants.
#[derive(Clone, Debug, PartialEq, Eq)]
#[allow(clippy::exhaustive_structs)]
pub struct VersionHistory {
    /// A list of unstable paths over this endpoint's history.
    ///
    /// For endpoint querying purposes, the last item will be used.
    unstable_paths: &'static [&'static str],

    /// A list of path versions, mapped to Matrix versions.
    ///
    /// Sorted (ascending) by Matrix version, will not mix major versions.
    stable_paths: &'static [(MatrixVersion, &'static str)],

    /// The Matrix version that deprecated this endpoint.
    ///
    /// Deprecation often precedes one Matrix version before removal.
    ///
    /// This will make [`try_into_http_request`](super::OutgoingRequest::try_into_http_request)
    /// emit a warning, see the corresponding documentation for more information.
    deprecated: Option<MatrixVersion>,

    /// The Matrix version that removed this endpoint.
    ///
    /// This will make [`try_into_http_request`](super::OutgoingRequest::try_into_http_request)
    /// emit an error, see the corresponding documentation for more information.
    removed: Option<MatrixVersion>,
}

impl VersionHistory {
    /// Constructs an instance of [`VersionHistory`], erroring on compilation if it does not pass
    /// invariants.
    ///
    /// Specifically, this checks the following invariants:
    /// - Path Arguments are equal (in order, amount, and argument name) in all path strings
    /// - In stable_paths:
    ///   - matrix versions are in ascending order
    ///   - no matrix version is referenced twice
    /// - deprecated's version comes after the latest version mentioned in stable_paths, except for
    ///   version 1.0, and only if any stable path is defined
    /// - removed comes after deprecated, or after the latest referenced stable_paths, like
    ///   deprecated
    pub const fn new(
        unstable_paths: &'static [&'static str],
        stable_paths: &'static [(MatrixVersion, &'static str)],
        deprecated: Option<MatrixVersion>,
        removed: Option<MatrixVersion>,
    ) -> Self {
        use konst::{iter, slice, string};

        const fn check_path_is_valid(path: &'static str) {
            iter::for_each!(path_b in slice::iter(path.as_bytes()) => {
                match *path_b {
                    0x21..=0x7E => {},
                    _ => panic!("path contains invalid (non-ascii or whitespace) characters")
                }
            });
        }

        const fn check_path_args_equal(first: &'static str, second: &'static str) {
            let mut second_iter = string::split(second, "/").next();

            iter::for_each!(first_s in string::split(first, "/") => {
                if let Some(first_arg) = string::strip_prefix(first_s, ":") {
                    let second_next_arg: Option<&'static str> = loop {
                        let (second_s, second_n_iter) = match second_iter {
                            Some(tuple) => tuple,
                            None => break None,
                        };

                        let maybe_second_arg = string::strip_prefix(second_s, ":");

                        second_iter = second_n_iter.next();

                        if let Some(second_arg) = maybe_second_arg {
                            break Some(second_arg);
                        }
                    };

                    if let Some(second_next_arg) = second_next_arg {
                        if !string::eq_str(second_next_arg, first_arg) {
                            panic!("Path Arguments do not match");
                        }
                    } else {
                        panic!("Amount of Path Arguments do not match");
                    }
                }
            });

            // If second iterator still has some values, empty first.
            while let Some((second_s, second_n_iter)) = second_iter {
                if string::starts_with(second_s, ":") {
                    panic!("Amount of Path Arguments do not match");
                }
                second_iter = second_n_iter.next();
            }
        }

        // The path we're going to use to compare all other paths with
        let ref_path: &str = if let Some(s) = unstable_paths.first() {
            s
        } else if let Some((_, s)) = stable_paths.first() {
            s
        } else {
            panic!("No paths supplied")
        };

        iter::for_each!(unstable_path in slice::iter(unstable_paths) => {
            check_path_is_valid(unstable_path);
            check_path_args_equal(ref_path, unstable_path);
        });

        let mut prev_seen_version: Option<MatrixVersion> = None;

        iter::for_each!(stable_path in slice::iter(stable_paths) => {
            check_path_is_valid(stable_path.1);
            check_path_args_equal(ref_path, stable_path.1);

            let current_version = stable_path.0;

            if let Some(prev_seen_version) = prev_seen_version {
                let cmp_result = current_version.const_ord(&prev_seen_version);

                if cmp_result.is_eq() {
                    // Found a duplicate, current == previous
                    panic!("Duplicate matrix version in stable_paths")
                } else if cmp_result.is_lt() {
                    // Found an older version, current < previous
                    panic!("No ascending order in stable_paths")
                }
            }

            prev_seen_version = Some(current_version);
        });

        if let Some(deprecated) = deprecated {
            if let Some(prev_seen_version) = prev_seen_version {
                let ord_result = prev_seen_version.const_ord(&deprecated);
                if !deprecated.is_legacy() && ord_result.is_eq() {
                    // prev_seen_version == deprecated, except for 1.0.
                    // It is possible that an endpoint was both made stable and deprecated in the
                    // legacy versions.
                    panic!("deprecated version is equal to latest stable path version")
                } else if ord_result.is_gt() {
                    // prev_seen_version > deprecated
                    panic!("deprecated version is older than latest stable path version")
                }
            } else {
                panic!("Defined deprecated version while no stable path exists")
            }
        }

        if let Some(removed) = removed {
            if let Some(deprecated) = deprecated {
                let ord_result = deprecated.const_ord(&removed);
                if ord_result.is_eq() {
                    // deprecated == removed
                    panic!("removed version is equal to deprecated version")
                } else if ord_result.is_gt() {
                    // deprecated > removed
                    panic!("removed version is older than deprecated version")
                }
            } else {
                panic!("Defined removed version while no deprecated version exists")
            }
        }

        VersionHistory { unstable_paths, stable_paths, deprecated, removed }
    }

    // This function helps picks the right path (or an error) from a set of Matrix versions.
    fn select_path(&self, versions: &[MatrixVersion]) -> Result<&'static str, IntoHttpError> {
        match self.versioning_decision_for(versions) {
            VersioningDecision::Removed => Err(IntoHttpError::EndpointRemoved(
                self.removed.expect("VersioningDecision::Removed implies metadata.removed"),
            )),
            VersioningDecision::Stable { any_deprecated, all_deprecated, any_removed } => {
                if any_removed {
                    if all_deprecated {
                        warn!(
                            "endpoint is removed in some (and deprecated in ALL) \
                             of the following versions: {versions:?}",
                        );
                    } else if any_deprecated {
                        warn!(
                            "endpoint is removed (and deprecated) in some of the \
                             following versions: {versions:?}",
                        );
                    } else {
                        unreachable!("any_removed implies *_deprecated");
                    }
                } else if all_deprecated {
                    warn!(
                        "endpoint is deprecated in ALL of the following versions: \
                         {versions:?}",
                    );
                } else if any_deprecated {
                    warn!(
                        "endpoint is deprecated in some of the following versions: \
                         {versions:?}",
                    );
                }

                Ok(self
                    .stable_endpoint_for(versions)
                    .expect("VersioningDecision::Stable implies that a stable path exists"))
            }
            VersioningDecision::Unstable => self.unstable().ok_or(IntoHttpError::NoUnstablePath),
        }
    }

    /// Will decide how a particular set of Matrix versions sees an endpoint.
    ///
    /// It will only return `Deprecated` or `Removed` if all versions denote it.
    ///
    /// In other words, if in any version it tells it supports the endpoint in a stable fashion,
    /// this will return `Stable`, even if some versions in this set will denote deprecation or
    /// removal.
    ///
    /// If resulting [`VersioningDecision`] is `Stable`, it will also detail if any version denoted
    /// deprecation or removal.
    pub fn versioning_decision_for(&self, versions: &[MatrixVersion]) -> VersioningDecision {
        let greater_or_equal_any =
            |version: MatrixVersion| versions.iter().any(|v| v.is_superset_of(version));
        let greater_or_equal_all =
            |version: MatrixVersion| versions.iter().all(|v| v.is_superset_of(version));

        // Check if all versions removed this endpoint.
        if self.removed.is_some_and(greater_or_equal_all) {
            return VersioningDecision::Removed;
        }

        // Check if *any* version marks this endpoint as stable.
        if self.added_in().is_some_and(greater_or_equal_any) {
            let all_deprecated = self.deprecated.is_some_and(greater_or_equal_all);

            return VersioningDecision::Stable {
                any_deprecated: all_deprecated || self.deprecated.is_some_and(greater_or_equal_any),
                all_deprecated,
                any_removed: self.removed.is_some_and(greater_or_equal_any),
            };
        }

        VersioningDecision::Unstable
    }

    /// Returns the *first* version this endpoint was added in.
    ///
    /// Is `None` when this endpoint is unstable/unreleased.
    pub fn added_in(&self) -> Option<MatrixVersion> {
        self.stable_paths.first().map(|(v, _)| *v)
    }

    /// Returns the Matrix version that deprecated this endpoint, if any.
    pub fn deprecated_in(&self) -> Option<MatrixVersion> {
        self.deprecated
    }

    /// Returns the Matrix version that removed this endpoint, if any.
    pub fn removed_in(&self) -> Option<MatrixVersion> {
        self.removed
    }

    /// Picks the last unstable path, if it exists.
    pub fn unstable(&self) -> Option<&'static str> {
        self.unstable_paths.last().copied()
    }

    /// Returns all path variants in canon form, for use in server routers.
    pub fn all_paths(&self) -> impl Iterator<Item = &'static str> {
        self.unstable_paths().chain(self.stable_paths().map(|(_, path)| path))
    }

    /// Returns all unstable path variants in canon form.
    pub fn unstable_paths(&self) -> impl Iterator<Item = &'static str> {
        self.unstable_paths.iter().copied()
    }

    /// Returns all stable path variants in canon form, with corresponding Matrix version.
    pub fn stable_paths(&self) -> impl Iterator<Item = (MatrixVersion, &'static str)> {
        self.stable_paths.iter().map(|(version, data)| (*version, *data))
    }

    /// The path that should be used to query the endpoint, given a series of versions.
    ///
    /// This will pick the latest path that the version accepts.
    ///
    /// This will return an endpoint in the following format;
    /// - `/_matrix/client/versions`
    /// - `/_matrix/client/hello/:world` (`:world` is a path replacement parameter)
    ///
    /// Note: This will not keep in mind endpoint removals, check with
    /// [`versioning_decision_for`](VersionHistory::versioning_decision_for) to see if this endpoint
    /// is still available.
    pub fn stable_endpoint_for(&self, versions: &[MatrixVersion]) -> Option<&'static str> {
        // Go reverse, to check the "latest" version first.
        for (ver, path) in self.stable_paths.iter().rev() {
            // Check if any of the versions are equal or greater than the version the path needs.
            if versions.iter().any(|v| v.is_superset_of(*ver)) {
                return Some(path);
            }
        }

        None
    }
}

/// A versioning "decision" derived from a set of Matrix versions.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
#[allow(clippy::exhaustive_enums)]
pub enum VersioningDecision {
    /// The unstable endpoint should be used.
    Unstable,

    /// The stable endpoint should be used.
    Stable {
        /// If any version denoted deprecation.
        any_deprecated: bool,

        /// If *all* versions denoted deprecation.
        all_deprecated: bool,

        /// If any version denoted removal.
        any_removed: bool,
    },

    /// This endpoint was removed in all versions, it should not be used.
    Removed,
}

/// The Matrix versions Ruma currently understands to exist.
///
/// Matrix, since fall 2021, has a quarterly release schedule, using a global `vX.Y` versioning
/// scheme.
///
/// Every new minor version denotes stable support for endpoints in a *relatively*
/// backwards-compatible manner.
///
/// Matrix has a deprecation policy, read more about it here: <https://spec.matrix.org/latest/#deprecation-policy>.
///
/// Ruma keeps track of when endpoints are added, deprecated, and removed. It'll automatically
/// select the right endpoint stability variation to use depending on which Matrix versions you
/// pass to [`try_into_http_request`](super::OutgoingRequest::try_into_http_request), see its
/// respective documentation for more information.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
#[cfg_attr(not(feature = "unstable-exhaustive-types"), non_exhaustive)]
pub enum MatrixVersion {
    /// Version 1.0 of the Matrix specification.
    ///
    /// Retroactively defined as <https://spec.matrix.org/latest/#legacy-versioning>.
    V1_0,

    /// Version 1.1 of the Matrix specification, released in Q4 2021.
    ///
    /// See <https://spec.matrix.org/v1.1/>.
    V1_1,

    /// Version 1.2 of the Matrix specification, released in Q1 2022.
    ///
    /// See <https://spec.matrix.org/v1.2/>.
    V1_2,

    /// Version 1.3 of the Matrix specification, released in Q2 2022.
    ///
    /// See <https://spec.matrix.org/v1.3/>.
    V1_3,

    /// Version 1.4 of the Matrix specification, released in Q3 2022.
    ///
    /// See <https://spec.matrix.org/v1.4/>.
    V1_4,

    /// Version 1.5 of the Matrix specification, released in Q4 2022.
    ///
    /// See <https://spec.matrix.org/v1.5/>.
    V1_5,

    /// Version 1.6 of the Matrix specification, released in Q1 2023.
    ///
    /// See <https://spec.matrix.org/v1.6/>.
    V1_6,

    /// Version 1.7 of the Matrix specification, released in Q2 2023.
    ///
    /// See <https://spec.matrix.org/v1.7/>.
    V1_7,

    /// Version 1.8 of the Matrix specification, released in Q3 2023.
    ///
    /// See <https://spec.matrix.org/v1.8/>.
    V1_8,

    /// Version 1.9 of the Matrix specification, released in Q4 2023.
    ///
    /// See <https://spec.matrix.org/v1.9/>.
    V1_9,

    /// Version 1.10 of the Matrix specification, released in Q1 2024.
    ///
    /// See <https://spec.matrix.org/v1.10/>.
    V1_10,

    /// Version 1.11 of the Matrix specification, released in Q2 2024.
    ///
    /// See <https://spec.matrix.org/v1.11/>.
    V1_11,

    /// Version 1.12 of the Matrix specification, released in Q3 2024.
    ///
    /// See <https://spec.matrix.org/v1.12/>.
    V1_12,
}

impl TryFrom<&str> for MatrixVersion {
    type Error = UnknownVersionError;

    fn try_from(value: &str) -> Result<MatrixVersion, Self::Error> {
        use MatrixVersion::*;

        Ok(match value {
            // FIXME: these are likely not entirely correct; https://github.com/ruma/ruma/issues/852
            "v1.0" |
            // Additional definitions according to https://spec.matrix.org/latest/#legacy-versioning
            "r0.5.0" | "r0.6.0" | "r0.6.1" => V1_0,
            "v1.1" => V1_1,
            "v1.2" => V1_2,
            "v1.3" => V1_3,
            "v1.4" => V1_4,
            "v1.5" => V1_5,
            "v1.6" => V1_6,
            "v1.7" => V1_7,
            "v1.8" => V1_8,
            "v1.9" => V1_9,
            "v1.10" => V1_10,
            "v1.11" => V1_11,
            "v1.12" => V1_12,
            _ => return Err(UnknownVersionError),
        })
    }
}

impl FromStr for MatrixVersion {
    type Err = UnknownVersionError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        Self::try_from(s)
    }
}

impl MatrixVersion {
    /// Checks whether a version is compatible with another.
    ///
    /// A is compatible with B as long as B is equal or less, so long as A and B have the same
    /// major versions.
    ///
    /// For example, v1.2 is compatible with v1.1, as it is likely only some additions of
    /// endpoints on top of v1.1, but v1.1 would not be compatible with v1.2, as v1.1
    /// cannot represent all of v1.2, in a manner similar to set theory.
    ///
    /// Warning: Matrix has a deprecation policy, and Matrix versioning is not as
    /// straight-forward as this function makes it out to be. This function only exists
    /// to prune major version differences, and versions too new for `self`.
    ///
    /// This (considering if major versions are the same) is equivalent to a `self >= other`
    /// check.
    pub fn is_superset_of(self, other: Self) -> bool {
        let (major_l, minor_l) = self.into_parts();
        let (major_r, minor_r) = other.into_parts();
        major_l == major_r && minor_l >= minor_r
    }

    /// Decompose the Matrix version into its major and minor number.
    pub const fn into_parts(self) -> (u8, u8) {
        match self {
            MatrixVersion::V1_0 => (1, 0),
            MatrixVersion::V1_1 => (1, 1),
            MatrixVersion::V1_2 => (1, 2),
            MatrixVersion::V1_3 => (1, 3),
            MatrixVersion::V1_4 => (1, 4),
            MatrixVersion::V1_5 => (1, 5),
            MatrixVersion::V1_6 => (1, 6),
            MatrixVersion::V1_7 => (1, 7),
            MatrixVersion::V1_8 => (1, 8),
            MatrixVersion::V1_9 => (1, 9),
            MatrixVersion::V1_10 => (1, 10),
            MatrixVersion::V1_11 => (1, 11),
            MatrixVersion::V1_12 => (1, 12),
        }
    }

    /// Try to turn a pair of (major, minor) version components back into a `MatrixVersion`.
    pub const fn from_parts(major: u8, minor: u8) -> Result<Self, UnknownVersionError> {
        match (major, minor) {
            (1, 0) => Ok(MatrixVersion::V1_0),
            (1, 1) => Ok(MatrixVersion::V1_1),
            (1, 2) => Ok(MatrixVersion::V1_2),
            (1, 3) => Ok(MatrixVersion::V1_3),
            (1, 4) => Ok(MatrixVersion::V1_4),
            (1, 5) => Ok(MatrixVersion::V1_5),
            (1, 6) => Ok(MatrixVersion::V1_6),
            (1, 7) => Ok(MatrixVersion::V1_7),
            (1, 8) => Ok(MatrixVersion::V1_8),
            (1, 9) => Ok(MatrixVersion::V1_9),
            (1, 10) => Ok(MatrixVersion::V1_10),
            (1, 11) => Ok(MatrixVersion::V1_11),
            (1, 12) => Ok(MatrixVersion::V1_12),
            _ => Err(UnknownVersionError),
        }
    }

    /// Constructor for use by the `metadata!` macro.
    ///
    /// Accepts string literals and parses them.
    #[doc(hidden)]
    pub const fn from_lit(lit: &'static str) -> Self {
        use konst::{option, primitive::parse_u8, result, string};

        let major: u8;
        let minor: u8;

        let mut lit_iter = string::split(lit, ".").next();

        {
            let (checked_first, checked_split) = option::unwrap!(lit_iter); // First iteration always succeeds

            major = result::unwrap_or_else!(parse_u8(checked_first), |_| panic!(
                "major version is not a valid number"
            ));

            lit_iter = checked_split.next();
        }

        match lit_iter {
            Some((checked_second, checked_split)) => {
                minor = result::unwrap_or_else!(parse_u8(checked_second), |_| panic!(
                    "minor version is not a valid number"
                ));

                lit_iter = checked_split.next();
            }
            None => panic!("could not find dot to denote second number"),
        }

        if lit_iter.is_some() {
            panic!("version literal contains more than one dot")
        }

        result::unwrap_or_else!(Self::from_parts(major, minor), |_| panic!(
            "not a valid version literal"
        ))
    }

    // Internal function to do ordering in const-fn contexts
    const fn const_ord(&self, other: &Self) -> Ordering {
        let self_parts = self.into_parts();
        let other_parts = other.into_parts();

        use konst::primitive::cmp::cmp_u8;

        let major_ord = cmp_u8(self_parts.0, other_parts.0);
        if major_ord.is_ne() {
            major_ord
        } else {
            cmp_u8(self_parts.1, other_parts.1)
        }
    }

    // Internal function to check if this version is the legacy (v1.0) version in const-fn contexts
    const fn is_legacy(&self) -> bool {
        let self_parts = self.into_parts();

        use konst::primitive::cmp::cmp_u8;

        cmp_u8(self_parts.0, 1).is_eq() && cmp_u8(self_parts.1, 0).is_eq()
    }

    /// Get the default [`RoomVersionId`] for this `MatrixVersion`.
    pub fn default_room_version(&self) -> RoomVersionId {
        match self {
            // <https://spec.matrix.org/historical/index.html#complete-list-of-room-versions>
            MatrixVersion::V1_0
            // <https://spec.matrix.org/v1.1/rooms/#complete-list-of-room-versions>
            | MatrixVersion::V1_1
            // <https://spec.matrix.org/v1.2/rooms/#complete-list-of-room-versions>
            | MatrixVersion::V1_2 => RoomVersionId::V6,
            // <https://spec.matrix.org/v1.3/rooms/#complete-list-of-room-versions>
            MatrixVersion::V1_3
            // <https://spec.matrix.org/v1.4/rooms/#complete-list-of-room-versions>
            | MatrixVersion::V1_4
            // <https://spec.matrix.org/v1.5/rooms/#complete-list-of-room-versions>
            | MatrixVersion::V1_5 => RoomVersionId::V9,
            // <https://spec.matrix.org/v1.6/rooms/#complete-list-of-room-versions>
            MatrixVersion::V1_6
            // <https://spec.matrix.org/v1.7/rooms/#complete-list-of-room-versions>
            | MatrixVersion::V1_7
            // <https://spec.matrix.org/v1.8/rooms/#complete-list-of-room-versions>
            | MatrixVersion::V1_8
            // <https://spec.matrix.org/v1.9/rooms/#complete-list-of-room-versions>
            | MatrixVersion::V1_9
            // <https://spec.matrix.org/v1.10/rooms/#complete-list-of-room-versions>
            | MatrixVersion::V1_10
            // <https://spec.matrix.org/v1.11/rooms/#complete-list-of-room-versions>
            | MatrixVersion::V1_11
            // <https://spec.matrix.org/v1.12/rooms/#complete-list-of-room-versions>
            | MatrixVersion::V1_12  => RoomVersionId::V10,
        }
    }
}

impl Display for MatrixVersion {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let (major, minor) = self.into_parts();
        f.write_str(&format!("v{major}.{minor}"))
    }
}

#[cfg(test)]
mod tests {
    use assert_matches2::assert_matches;
    use http::Method;

    use super::{
        AuthScheme,
        MatrixVersion::{self, V1_0, V1_1, V1_2, V1_3},
        Metadata, VersionHistory,
    };
    use crate::api::error::IntoHttpError;

    fn stable_only_metadata(stable_paths: &'static [(MatrixVersion, &'static str)]) -> Metadata {
        Metadata {
            method: Method::GET,
            rate_limited: false,
            authentication: AuthScheme::None,
            history: VersionHistory {
                unstable_paths: &[],
                stable_paths,
                deprecated: None,
                removed: None,
            },
        }
    }

    // TODO add test that can hook into tracing and verify the deprecation warning is emitted

    #[test]
    fn make_simple_endpoint_url() {
        let meta = stable_only_metadata(&[(V1_0, "/s")]);
        let url = meta.make_endpoint_url(&[V1_0], "https://example.org", &[], "").unwrap();
        assert_eq!(url, "https://example.org/s");
    }

    #[test]
    fn make_endpoint_url_with_path_args() {
        let meta = stable_only_metadata(&[(V1_0, "/s/:x")]);
        let url = meta.make_endpoint_url(&[V1_0], "https://example.org", &[&"123"], "").unwrap();
        assert_eq!(url, "https://example.org/s/123");
    }

    #[test]
    fn make_endpoint_url_with_path_args_with_dash() {
        let meta = stable_only_metadata(&[(V1_0, "/s/:x")]);
        let url =
            meta.make_endpoint_url(&[V1_0], "https://example.org", &[&"my-path"], "").unwrap();
        assert_eq!(url, "https://example.org/s/my-path");
    }

    #[test]
    fn make_endpoint_url_with_path_args_with_reserved_char() {
        let meta = stable_only_metadata(&[(V1_0, "/s/:x")]);
        let url = meta.make_endpoint_url(&[V1_0], "https://example.org", &[&"#path"], "").unwrap();
        assert_eq!(url, "https://example.org/s/%23path");
    }

    #[test]
    fn make_endpoint_url_with_query() {
        let meta = stable_only_metadata(&[(V1_0, "/s/")]);
        let url = meta.make_endpoint_url(&[V1_0], "https://example.org", &[], "foo=bar").unwrap();
        assert_eq!(url, "https://example.org/s/?foo=bar");
    }

    #[test]
    #[should_panic]
    fn make_endpoint_url_wrong_num_path_args() {
        let meta = stable_only_metadata(&[(V1_0, "/s/:x")]);
        _ = meta.make_endpoint_url(&[V1_0], "https://example.org", &[], "");
    }

    const EMPTY: VersionHistory =
        VersionHistory { unstable_paths: &[], stable_paths: &[], deprecated: None, removed: None };

    #[test]
    fn select_latest_stable() {
        let hist = VersionHistory { stable_paths: &[(V1_1, "/s")], ..EMPTY };
        assert_matches!(hist.select_path(&[V1_0, V1_1]), Ok("/s"));
    }

    #[test]
    fn select_unstable() {
        let hist = VersionHistory { unstable_paths: &["/u"], ..EMPTY };
        assert_matches!(hist.select_path(&[V1_0]), Ok("/u"));
    }

    #[test]
    fn select_r0() {
        let hist = VersionHistory { stable_paths: &[(V1_0, "/r")], ..EMPTY };
        assert_matches!(hist.select_path(&[V1_0]), Ok("/r"));
    }

    #[test]
    fn select_removed_err() {
        let hist = VersionHistory {
            stable_paths: &[(V1_0, "/r"), (V1_1, "/s")],
            unstable_paths: &["/u"],
            deprecated: Some(V1_2),
            removed: Some(V1_3),
        };
        assert_matches!(hist.select_path(&[V1_3]), Err(IntoHttpError::EndpointRemoved(V1_3)));
    }

    #[test]
    fn partially_removed_but_stable() {
        let hist = VersionHistory {
            stable_paths: &[(V1_0, "/r"), (V1_1, "/s")],
            unstable_paths: &[],
            deprecated: Some(V1_2),
            removed: Some(V1_3),
        };
        assert_matches!(hist.select_path(&[V1_2]), Ok("/s"));
    }

    #[test]
    fn no_unstable() {
        let hist = VersionHistory { stable_paths: &[(V1_1, "/s")], ..EMPTY };
        assert_matches!(hist.select_path(&[V1_0]), Err(IntoHttpError::NoUnstablePath));
    }

    #[test]
    fn version_literal() {
        const LIT: MatrixVersion = MatrixVersion::from_lit("1.0");

        assert_eq!(LIT, V1_0);
    }
}