| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `crates/stdx/src/assert.rs`."><title>assert.rs - source</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Italic-81dc35de.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-MediumItalic-ccf7e434.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../../static.files/normalize-9960930a.css"><link rel="stylesheet" href="../../static.files/rustdoc-84e720fa.css"><meta name="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="stdx" data-themes="" data-resource-suffix="" data-rustdoc-version="1.89.0 (29483883e 2025-08-04)" data-channel="1.89.0" data-search-js="search-92309212.js" data-settings-js="settings-5514c975.js" ><script src="../../static.files/storage-4e99c027.js"></script><script defer src="../../static.files/src-script-813739b1.js"></script><script defer src="../../src-files.js"></script><script defer src="../../static.files/main-fd3af306.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-32bb7600.css"></noscript><link rel="alternate icon" type="image/png" href="../../static.files/favicon-32x32-6580c154.png"><link rel="icon" type="image/svg+xml" href="../../static.files/favicon-044be391.svg"></head><body class="rustdoc src"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="src-sidebar-title"><h2>Files</h2></div></nav><div class="sidebar-resizer" title="Drag to resize sidebar"></div><main><rustdoc-search></rustdoc-search><section id="main-content" class="content"><div class="main-heading"><h1><div class="sub-heading">stdx/</div>assert.rs</h1><rustdoc-toolbar></rustdoc-toolbar></div><div class="example-wrap digits-3"><pre class="rust"><code><a href=#1 id=1 data-nosnippet>1</a><span class="comment">// Vendored from https://github.com/matklad/always-assert/commit/4cf564eea6fcf18b30c3c3483a611004dc03afbb |
| <a href=#2 id=2 data-nosnippet>2</a></span><span class="doccomment">//! Recoverable assertions, inspired by [the use of `assert()` in |
| <a href=#3 id=3 data-nosnippet>3</a>//! SQLite](https://www.sqlite.org/assert.html). |
| <a href=#4 id=4 data-nosnippet>4</a>//! |
| <a href=#5 id=5 data-nosnippet>5</a>//! `never!` and `always!` return the actual value of the condition if |
| <a href=#6 id=6 data-nosnippet>6</a>//! `debug_assertions` are disabled. |
| <a href=#7 id=7 data-nosnippet>7</a>//! |
| <a href=#8 id=8 data-nosnippet>8</a>//! Use them when terminating on assertion failure is worse than continuing. |
| <a href=#9 id=9 data-nosnippet>9</a>//! |
| <a href=#10 id=10 data-nosnippet>10</a>//! One example would be a critical application like a database: |
| <a href=#11 id=11 data-nosnippet>11</a>//! |
| <a href=#12 id=12 data-nosnippet>12</a>//! ```ignore |
| <a href=#13 id=13 data-nosnippet>13</a>//! use stdx::never; |
| <a href=#14 id=14 data-nosnippet>14</a>//! |
| <a href=#15 id=15 data-nosnippet>15</a>//! fn apply_transaction(&mut self, tx: Transaction) -> Result<(), TransactionAborted> { |
| <a href=#16 id=16 data-nosnippet>16</a>//! let delta = self.compute_delta(&tx); |
| <a href=#17 id=17 data-nosnippet>17</a>//! |
| <a href=#18 id=18 data-nosnippet>18</a>//! if never!(!self.check_internal_invariant(&delta)) { |
| <a href=#19 id=19 data-nosnippet>19</a>//! // Ok, something in this transaction messed up our internal state. |
| <a href=#20 id=20 data-nosnippet>20</a>//! // This really shouldn't be happening, and this signifies a bug. |
| <a href=#21 id=21 data-nosnippet>21</a>//! // Luckily, we can recover by just rejecting the transaction. |
| <a href=#22 id=22 data-nosnippet>22</a>//! return abort_transaction(tx); |
| <a href=#23 id=23 data-nosnippet>23</a>//! } |
| <a href=#24 id=24 data-nosnippet>24</a>//! self.commit(delta); |
| <a href=#25 id=25 data-nosnippet>25</a>//! Ok(()) |
| <a href=#26 id=26 data-nosnippet>26</a>//! } |
| <a href=#27 id=27 data-nosnippet>27</a>//! ``` |
| <a href=#28 id=28 data-nosnippet>28</a>//! |
| <a href=#29 id=29 data-nosnippet>29</a>//! Another example is assertions about non-critical functionality in usual apps |
| <a href=#30 id=30 data-nosnippet>30</a>//! |
| <a href=#31 id=31 data-nosnippet>31</a>//! ```ignore |
| <a href=#32 id=32 data-nosnippet>32</a>//! use stdx::never; |
| <a href=#33 id=33 data-nosnippet>33</a>//! |
| <a href=#34 id=34 data-nosnippet>34</a>//! let english_message = "super app installed!" |
| <a href=#35 id=35 data-nosnippet>35</a>//! let mut local_message = localize(english_message); |
| <a href=#36 id=36 data-nosnippet>36</a>//! if never!(local_message.is_empty(), "missing localization for {}", english_message) { |
| <a href=#37 id=37 data-nosnippet>37</a>//! // We localized all the messages but this one slipper through the cracks? |
| <a href=#38 id=38 data-nosnippet>38</a>//! // Better to show the english one then than to fail outright; |
| <a href=#39 id=39 data-nosnippet>39</a>//! local_message = english_message; |
| <a href=#40 id=40 data-nosnippet>40</a>//! } |
| <a href=#41 id=41 data-nosnippet>41</a>//! println!("{}", local_message); |
| <a href=#42 id=42 data-nosnippet>42</a>//! ``` |
| <a href=#43 id=43 data-nosnippet>43</a> |
| <a href=#44 id=44 data-nosnippet>44</a>/// Asserts that the condition is always true and returns its actual value. |
| <a href=#45 id=45 data-nosnippet>45</a>/// |
| <a href=#46 id=46 data-nosnippet>46</a>/// If the condition is true does nothing and and evaluates to true. |
| <a href=#47 id=47 data-nosnippet>47</a>/// |
| <a href=#48 id=48 data-nosnippet>48</a>/// If the condition is false: |
| <a href=#49 id=49 data-nosnippet>49</a>/// * panics if `force` feature or `debug_assertions` are enabled, |
| <a href=#50 id=50 data-nosnippet>50</a>/// * logs an error if the `tracing` feature is enabled, |
| <a href=#51 id=51 data-nosnippet>51</a>/// * evaluates to false. |
| <a href=#52 id=52 data-nosnippet>52</a>/// |
| <a href=#53 id=53 data-nosnippet>53</a>/// Accepts `format!` style arguments. |
| <a href=#54 id=54 data-nosnippet>54</a></span><span class="attr">#[macro_export] |
| <a href=#55 id=55 data-nosnippet>55</a></span><span class="macro">macro_rules!</span> always { |
| <a href=#56 id=56 data-nosnippet>56</a> (<span class="macro-nonterminal">$cond</span>:expr) => { |
| <a href=#57 id=57 data-nosnippet>57</a> <span class="macro-nonterminal">$</span><span class="macro">crate::always!</span>(<span class="macro-nonterminal">$cond</span>, <span class="string">"assertion failed: {}"</span>, <span class="macro">stringify!</span>(<span class="macro-nonterminal">$cond</span>)) |
| <a href=#58 id=58 data-nosnippet>58</a> }; |
| <a href=#59 id=59 data-nosnippet>59</a> |
| <a href=#60 id=60 data-nosnippet>60</a> (<span class="macro-nonterminal">$cond</span>:expr, <span class="macro-nonterminal">$fmt</span>:literal $(<span class="macro-nonterminal">$arg</span>:tt)<span class="kw-2">*</span>) => {{ |
| <a href=#61 id=61 data-nosnippet>61</a> <span class="kw">let </span>cond = <span class="macro-nonterminal">$cond</span>; |
| <a href=#62 id=62 data-nosnippet>62</a> <span class="kw">if </span><span class="macro">cfg!</span>(debug_assertions) || <span class="macro-nonterminal">$crate::assert::__FORCE </span>{ |
| <a href=#63 id=63 data-nosnippet>63</a> <span class="macro">assert!</span>(cond, <span class="macro-nonterminal">$fmt </span>$(<span class="macro-nonterminal">$arg</span>)<span class="kw-2">*</span>); |
| <a href=#64 id=64 data-nosnippet>64</a> } |
| <a href=#65 id=65 data-nosnippet>65</a> <span class="kw">if </span>!cond { |
| <a href=#66 id=66 data-nosnippet>66</a> <span class="macro-nonterminal">$</span><span class="macro">crate::assert::__tracing_error!</span>(<span class="macro-nonterminal">$fmt </span>$(<span class="macro-nonterminal">$arg</span>)<span class="kw-2">*</span>); |
| <a href=#67 id=67 data-nosnippet>67</a> } |
| <a href=#68 id=68 data-nosnippet>68</a> cond |
| <a href=#69 id=69 data-nosnippet>69</a> }}; |
| <a href=#70 id=70 data-nosnippet>70</a>} |
| <a href=#71 id=71 data-nosnippet>71</a> |
| <a href=#72 id=72 data-nosnippet>72</a><span class="doccomment">/// Asserts that the condition is never true and returns its actual value. |
| <a href=#73 id=73 data-nosnippet>73</a>/// |
| <a href=#74 id=74 data-nosnippet>74</a>/// If the condition is false does nothing and and evaluates to false. |
| <a href=#75 id=75 data-nosnippet>75</a>/// |
| <a href=#76 id=76 data-nosnippet>76</a>/// If the condition is true: |
| <a href=#77 id=77 data-nosnippet>77</a>/// * panics if `force` feature or `debug_assertions` are enabled, |
| <a href=#78 id=78 data-nosnippet>78</a>/// * logs an error if the `tracing` feature is enabled, |
| <a href=#79 id=79 data-nosnippet>79</a>/// * evaluates to true. |
| <a href=#80 id=80 data-nosnippet>80</a>/// |
| <a href=#81 id=81 data-nosnippet>81</a>/// Accepts `format!` style arguments. |
| <a href=#82 id=82 data-nosnippet>82</a>/// |
| <a href=#83 id=83 data-nosnippet>83</a>/// Empty condition is equivalent to false: |
| <a href=#84 id=84 data-nosnippet>84</a>/// |
| <a href=#85 id=85 data-nosnippet>85</a>/// ```ignore |
| <a href=#86 id=86 data-nosnippet>86</a>/// never!("oups") ~= unreachable!("oups") |
| <a href=#87 id=87 data-nosnippet>87</a>/// ``` |
| <a href=#88 id=88 data-nosnippet>88</a></span><span class="attr">#[macro_export] |
| <a href=#89 id=89 data-nosnippet>89</a></span><span class="macro">macro_rules!</span> never { |
| <a href=#90 id=90 data-nosnippet>90</a> (<span class="bool-val">true </span>$(<span class="macro-nonterminal">$tt</span>:tt)<span class="kw-2">*</span>) => { <span class="macro-nonterminal">$</span><span class="macro">crate::never!</span>((<span class="bool-val">true</span>) $(<span class="macro-nonterminal">$tt</span>)<span class="kw-2">*</span>) }; |
| <a href=#91 id=91 data-nosnippet>91</a> (<span class="bool-val">false </span>$(<span class="macro-nonterminal">$tt</span>:tt)<span class="kw-2">*</span>) => { <span class="macro-nonterminal">$</span><span class="macro">crate::never!</span>((<span class="bool-val">false</span>) $(<span class="macro-nonterminal">$tt</span>)<span class="kw-2">*</span>) }; |
| <a href=#92 id=92 data-nosnippet>92</a> () => { <span class="macro-nonterminal">$</span><span class="macro">crate::never!</span>(<span class="string">"assertion failed: entered unreachable code"</span>) }; |
| <a href=#93 id=93 data-nosnippet>93</a> (<span class="macro-nonterminal">$fmt</span>:literal $(, $(<span class="macro-nonterminal">$arg</span>:tt)<span class="kw-2">*</span>)<span class="question-mark">?</span>) => {{ |
| <a href=#94 id=94 data-nosnippet>94</a> <span class="kw">if </span><span class="macro">cfg!</span>(debug_assertions) || <span class="macro-nonterminal">$crate::assert::__FORCE </span>{ |
| <a href=#95 id=95 data-nosnippet>95</a> <span class="macro">unreachable!</span>(<span class="macro-nonterminal">$fmt </span>$(, $(<span class="macro-nonterminal">$arg</span>)<span class="kw-2">*</span>)<span class="question-mark">?</span>); |
| <a href=#96 id=96 data-nosnippet>96</a> } |
| <a href=#97 id=97 data-nosnippet>97</a> <span class="macro-nonterminal">$</span><span class="macro">crate::assert::__tracing_error!</span>(<span class="macro-nonterminal">$fmt </span>$(, $(<span class="macro-nonterminal">$arg</span>)<span class="kw-2">*</span>)<span class="question-mark">?</span>); |
| <a href=#98 id=98 data-nosnippet>98</a> }}; |
| <a href=#99 id=99 data-nosnippet>99</a> |
| <a href=#100 id=100 data-nosnippet>100</a> (<span class="macro-nonterminal">$cond</span>:expr) => {{ |
| <a href=#101 id=101 data-nosnippet>101</a> <span class="kw">let </span>cond = !<span class="macro-nonterminal">$</span><span class="macro">crate::always!</span>(!<span class="macro-nonterminal">$cond</span>); |
| <a href=#102 id=102 data-nosnippet>102</a> cond |
| <a href=#103 id=103 data-nosnippet>103</a> }}; |
| <a href=#104 id=104 data-nosnippet>104</a> |
| <a href=#105 id=105 data-nosnippet>105</a> (<span class="macro-nonterminal">$cond</span>:expr, <span class="macro-nonterminal">$fmt</span>:literal $(<span class="macro-nonterminal">$arg</span>:tt)<span class="kw-2">*</span>) => {{ |
| <a href=#106 id=106 data-nosnippet>106</a> <span class="kw">let </span>cond = !<span class="macro-nonterminal">$</span><span class="macro">crate::always!</span>(!<span class="macro-nonterminal">$cond</span>, <span class="macro-nonterminal">$fmt </span>$(<span class="macro-nonterminal">$arg</span>)<span class="kw-2">*</span>); |
| <a href=#107 id=107 data-nosnippet>107</a> cond |
| <a href=#108 id=108 data-nosnippet>108</a> }}; |
| <a href=#109 id=109 data-nosnippet>109</a>} |
| <a href=#110 id=110 data-nosnippet>110</a> |
| <a href=#111 id=111 data-nosnippet>111</a><span class="attr">#[doc(hidden)] |
| <a href=#112 id=112 data-nosnippet>112</a></span><span class="kw">pub use </span>tracing::error <span class="kw">as </span>__tracing_error; |
| <a href=#113 id=113 data-nosnippet>113</a> |
| <a href=#114 id=114 data-nosnippet>114</a><span class="attr">#[doc(hidden)] |
| <a href=#115 id=115 data-nosnippet>115</a></span><span class="kw">pub const </span>__FORCE: bool = <span class="macro">cfg!</span>(feature = <span class="string">"force-always-assert"</span>);</code></pre></div></section></main></body></html> |
