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    <title>MongoDB Jira</title>
    <link>https://jira.mongodb.org</link>
    <description>This file is an XML representation of an issue</description>
    <language>en-us</language>    <build-info>
        <version>9.7.1</version>
        <build-number>970001</build-number>
        <build-date>13-04-2023</build-date>
    </build-info>


<item>
            <title>[GODRIVER-2426] Distinct does not provide unmarshalling api</title>
                <link>https://jira.mongodb.org/browse/GODRIVER-2426</link>
                <project id="14289" key="GODRIVER">Go Driver</project>
                    <description>&lt;div class=&quot;panel&quot; style=&quot;background-color: #fafbfc;border-width: 1px;&quot;&gt;&lt;div class=&quot;panelContent&quot; style=&quot;background-color: #fafbfc;&quot;&gt;
&lt;h3&gt;&lt;a name=&quot;Summary&quot;&gt;&lt;/a&gt;&lt;b&gt;Summary&lt;/b&gt;&lt;/h3&gt;

&lt;p&gt;Consider the difference between these interfaces:&lt;/p&gt;

&lt;p&gt;&#160;&lt;/p&gt;
&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
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						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;func (c *Cursor) All(ctx context.Context, results interface{}) error&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
			&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;
&lt;p&gt;&#160;&lt;/p&gt;

&lt;p&gt;and&lt;/p&gt;
&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;func (coll *Collection) Distinct(ctx context.Context, fieldName string, filter interface{},&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;    opts ...*options.DistinctOptions) ([]interface{}, error)&lt;/span&gt;&lt;/pre&gt;
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		&lt;/tr&gt;
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&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;
&lt;p&gt;&#160;&lt;/p&gt;

&lt;p&gt;In the former case, result is unmarshal-ed into user-provided slice, and in the latter, provided as &lt;tt&gt;[]interface&lt;/tt&gt; which is populated via a code like this:&lt;/p&gt;

&lt;p&gt;&#160;&lt;/p&gt;
&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;for i, val := range values {&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;    raw := bson.RawValue{Type: val.Type, Value: val.Data}&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;    err = *raw.Unmarshal(&amp;amp;retArray[i])&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &#160; &#160; if err != nil {&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &#160; &#160; &#160; &#160; return nil, err&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &#160; &#160; }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;}&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
			&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;
&lt;p&gt;&#160;&lt;/p&gt;

&lt;p&gt;This proves problematic for a caller if you want to provide the same api with user-provided slices.&lt;/p&gt;

&lt;p&gt;Why would you want this?&lt;/p&gt;

&lt;p&gt;For example, if the field in question is a custom bson-marshalled type, and you wish to have the result as a slice of this type. Or if you simply do not wish to spoil your business logic with extra type checks and conversions.&#160;&lt;/p&gt;

&lt;p&gt;&#160;&lt;/p&gt;

&lt;p&gt;A list of workarounds appears to be:&lt;/p&gt;
&lt;ol&gt;
	&lt;li&gt;Write a conversion code with heavy use of reflection (needs PoC)&lt;/li&gt;
	&lt;li&gt;Write a conversion code that marshals the result back into Raw and then marshals into user-provided slice (poor performance, needs PoC)&lt;/li&gt;
	&lt;li&gt;Use public &lt;tt&gt;operation.NewDistinct()&lt;/tt&gt; and implement the desired functionality outside of the driver (needs PoC)&lt;/li&gt;
	&lt;li&gt;Change the code of the driver to allow for return of the original &lt;tt&gt;DistinctResult&lt;/tt&gt; or to provide the desired api&lt;/li&gt;
&lt;/ol&gt;


&lt;p&gt;We currently consider option 4 and will be happy to send a patch upstream, but it is best to first discuss if such change would be welcome.&#160;&lt;/p&gt;
&lt;h3&gt;&lt;a name=&quot;%C2%A0&quot;&gt;&lt;/a&gt;&#160;&lt;/h3&gt;
&lt;h3&gt;&lt;a name=&quot;Motivation&quot;&gt;&lt;/a&gt;&lt;b&gt;Motivation&lt;/b&gt;&lt;/h3&gt;
&lt;h4&gt;&lt;a name=&quot;Whoistheaffectedenduser%3F&quot;&gt;&lt;/a&gt;Who is the affected end user?&lt;/h4&gt;

&lt;p&gt;Anyone who would use Distinct() in a general purpose code.&lt;/p&gt;
&lt;h4&gt;&lt;a name=&quot;Howdoesthisaffecttheenduser%3F&quot;&gt;&lt;/a&gt;How does this affect the end user?&lt;/h4&gt;

&lt;p&gt;They need to implement a workaround.&lt;/p&gt;
&lt;h4&gt;&lt;a name=&quot;Howlikelyisitthatthisproblemorusecasewilloccur%3F&quot;&gt;&lt;/a&gt;How likely is it that this problem or use case will occur?&lt;/h4&gt;

&lt;p&gt;Any usage, possibly depending on the usage pattern.&lt;/p&gt;
&lt;h4&gt;&lt;a name=&quot;Iftheproblemdoesoccur%2Cwhataretheconsequencesandhowseverearethey%3F&quot;&gt;&lt;/a&gt;If the problem does occur, what are the consequences and how severe are they?&lt;/h4&gt;

&lt;p&gt;A need to implement a workaround.&lt;/p&gt;
&lt;h4&gt;&lt;a name=&quot;Isthisissueurgent%3F&quot;&gt;&lt;/a&gt;Is this issue urgent?&lt;/h4&gt;

&lt;p&gt;No.&lt;/p&gt;
&lt;h4&gt;&lt;a name=&quot;Isthisticketrequiredbyadownstreamteam%3F&quot;&gt;&lt;/a&gt;Is this ticket required by a downstream team?&lt;/h4&gt;

&lt;p&gt;No.&lt;/p&gt;
&lt;h4&gt;&lt;a name=&quot;Isthisticketonlyfortests%3F&quot;&gt;&lt;/a&gt;Is this ticket only for tests?&lt;/h4&gt;

&lt;p&gt;No.&lt;/p&gt;
&lt;/div&gt;&lt;/div&gt;</description>
                <environment></environment>
        <key id="2049530">GODRIVER-2426</key>
            <summary>Distinct does not provide unmarshalling api</summary>
                <type id="4" iconUrl="https://jira.mongodb.org/secure/viewavatar?size=xsmall&amp;avatarId=14710&amp;avatarType=issuetype">Improvement</type>
                                            <priority id="4" iconUrl="https://jira.mongodb.org/images/icons/priorities/minor.svg">Minor - P4</priority>
                        <status id="6" iconUrl="https://jira.mongodb.org/images/icons/statuses/closed.png" description="The issue is considered finished, the resolution is correct. Issues which are closed can be reopened.">Closed</status>
                    <statusCategory id="3" key="done" colorName="success"/>
                                    <resolution id="9">Done</resolution>
                                        <assignee username="benji.rewis@mongodb.com">Benji Rewis</assignee>
                                    <reporter username="petr.ivanov.s@gmail.com">Peter Ivanov</reporter>
                        <labels>
                            <label>neweng</label>
                    </labels>
                <created>Wed, 18 May 2022 14:12:09 +0000</created>
                <updated>Wed, 29 Jun 2022 20:38:59 +0000</updated>
                            <resolved>Mon, 13 Jun 2022 21:14:23 +0000</resolved>
                                    <version>1.9.1</version>
                                                                        <votes>0</votes>
                                    <watches>2</watches>
                                                                                                                <comments>
                            <comment id="4649040" author="benji.rewis" created="Wed, 29 Jun 2022 20:38:51 +0000"  >&lt;p&gt;Gotcha, I&apos;m not sure I can think of a way to unmarshal from a slice of BSON values returned from the server into an interface{} without the use of either reflection or generics... Let me know if you have any luck there or think of a method that&apos;s not &lt;tt&gt;DistinctCursor&lt;/tt&gt; that may be helpful for your use-case.&lt;/p&gt;

&lt;blockquote&gt;
&lt;p&gt;for someone who knows the concrete type of the result it solves almost all problems.&lt;/p&gt;&lt;/blockquote&gt;

&lt;p&gt;I agree, and I think that&apos;s probably strong enough motivation to add the method.&lt;/p&gt;</comment>
                            <comment id="4647302" author="petr.ivanov.s@gmail.com" created="Wed, 29 Jun 2022 11:26:10 +0000"  >&lt;p&gt;Yes, party. As we discussed before, it is a partial solution and it is still better than nothing. Then again, for someone who knows the concrete type of the result it solves alsmost all problems.&lt;/p&gt;

&lt;p&gt;(Come to think of it, I may be able to remove the reflection with the use of generics. I&apos;ll give it a try at some point.)&lt;/p&gt;</comment>
                            <comment id="4645694" author="benji.rewis" created="Tue, 28 Jun 2022 18:08:12 +0000"  >&lt;p&gt;Ah I understand. If we provided a &lt;tt&gt;DistinctCursor&lt;/tt&gt; method on &lt;tt&gt;Collection&lt;/tt&gt;&#160;that&#160;returned a &lt;tt&gt;Cursor&lt;/tt&gt;&#160;that could iterate over the distinct values, would that help your use-case? I&apos;m guessing not, as a &lt;tt&gt;Cursor&lt;/tt&gt; represents a set of &lt;tt&gt;bson.Raw&lt;/tt&gt; values that would still have to be appended to a user-provided interface{} with reflect logic. What API would be helpful?&lt;/p&gt;</comment>
                            <comment id="4637779" author="petr.ivanov.s@gmail.com" created="Fri, 24 Jun 2022 12:00:57 +0000"  >&lt;p&gt;What I mean is a piece of code like this:&lt;/p&gt;

&lt;p&gt;&#160;&lt;/p&gt;
&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;func unmarshalSliceRawValue(ctx context.Context, result &lt;/span&gt;&lt;span style=&quot;color: #006699; font-weight: bold; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;interface&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;{}, raw []bson.RawValue) error {&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; resultv := reflect.ValueOf(result)&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &lt;/span&gt;&lt;span style=&quot;color: #006699; font-weight: bold; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;if&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; !isPtrToSlice(result) {&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;  &#160; &#160; &#160; panic(...)&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; sliceValue := resultv.Elem()&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; sliceValue = sliceValue.Slice(&lt;/span&gt;&lt;span style=&quot;color: #009900; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;0&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;, sliceValue.Cap())&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; elemType := sliceValue.Type().Elem()&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &lt;/span&gt;&lt;span style=&quot;color: #006699; font-weight: bold; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;for&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; i := &lt;/span&gt;&lt;span style=&quot;color: #009900; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;0&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;; i &amp;lt; len(raw); i++ {&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &#160; &#160; &lt;/span&gt;&lt;span style=&quot;color: #006699; font-weight: bold; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;if&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; sliceValue.Len() == i {&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &#160; &#160; &#160; &#160; elemPtr := reflect.New(elemType)&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;  &#160; &#160; &#160; &#160; &#160; err := unmarshal(ctx, raw[i], elemPtr.Interface())&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &#160; &#160; &#160; &#160; &lt;/span&gt;&lt;span style=&quot;color: #006699; font-weight: bold; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;if&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; err != nil {&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &lt;/span&gt;&lt;span style=&quot;color: #006699; font-weight: bold; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;return&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; err&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &#160; &#160; &#160; &#160; }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &#160; &#160; &#160; &#160; sliceValue = reflect.Append(sliceValue, elemPtr.Elem())&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &#160; &#160; &#160; &#160; sliceValue = sliceValue.Slice(&lt;/span&gt;&lt;span style=&quot;color: #009900; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;0&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;, sliceValue.Cap())&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &#160; &#160; } &lt;/span&gt;&lt;span style=&quot;color: #006699; font-weight: bold; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;else&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; {&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;  &#160; &#160; &#160; &#160; &#160; err := unmarshal(ctx, raw[i], sliceValue.Index(i).Addr().Interface())&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &#160; &#160; &#160; &#160; &lt;/span&gt;&lt;span style=&quot;color: #006699; font-weight: bold; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;if&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; err != nil {&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &lt;/span&gt;&lt;span style=&quot;color: #006699; font-weight: bold; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;return&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; err&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &#160; &#160; &#160; &#160; }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &#160; &#160; }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; }&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; resultv.Elem().Set(sliceValue.Slice(&lt;/span&gt;&lt;span style=&quot;color: #009900; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;0&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;, len(raw)))&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&#160; &#160; &lt;/span&gt;&lt;span style=&quot;color: #006699; font-weight: bold; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;return&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt; nil&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;}&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
			&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;
&lt;p&gt;&#160;&lt;/p&gt;

&lt;p&gt;That is, append slice with individual unmarshalled objects.&lt;/p&gt;</comment>
                            <comment id="4632606" author="benji.rewis" created="Wed, 22 Jun 2022 15:46:37 +0000"  >&lt;p&gt;Ah I did assume that there was a single concrete type that could represent the value of the field for the distinct key.&lt;/p&gt;
&lt;blockquote&gt;&lt;p&gt;And then I use quite a lot of &lt;tt&gt;reflect&lt;/tt&gt; to unmarshal individual values into a result slice that is provided by a caller.&lt;/p&gt;&lt;/blockquote&gt;
&lt;p&gt;I&apos;m a little confused what you mean here. Do you know the set of types that the fields for the distinct key could be? And, if so, are you using reflection to determine which of those types to unmarshal the individual values to? Would exposing a &lt;tt&gt;DistinctCursor&lt;/tt&gt; method (as proposed in &lt;a href=&quot;https://jira.mongodb.org/browse/GODRIVER-2444&quot; title=&quot;Consider a DistinctCursor collection method&quot; class=&quot;issue-link&quot; data-issue-key=&quot;GODRIVER-2444&quot;&gt;GODRIVER-2444&lt;/a&gt;) that returns a &lt;tt&gt;Cursor&lt;/tt&gt; help avoid that reflection? I&apos;m not sure I see how, as I imagine you&apos;d run into the same issue.&lt;/p&gt;

&lt;p&gt;&#160;&lt;/p&gt;</comment>
                            <comment id="4628383" author="petr.ivanov.s@gmail.com" created="Tue, 21 Jun 2022 10:08:02 +0000"  >&lt;p&gt;Benji, I&apos;m afraid its use is limited.&#160;&lt;/p&gt;

&lt;p&gt;The part of example that does show a way of making your own impl relies on knowing the concrete type of the result. In my case, this is impossible, otherwise I might have settled with the original driver api plus some conversion.&lt;/p&gt;

&lt;p&gt;I did manage to make it work, but my code is different. First, I decode the raw result to struct like this:&lt;/p&gt;
&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;type distinctResult struct {&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;  Values []bson.RawValue `bson:&lt;/span&gt;&lt;span style=&quot;color: blue; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;&quot;values&quot;&lt;/span&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;`&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;}&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
			&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;
&lt;p&gt;And then I use quite a lot of &lt;tt&gt;reflect&lt;/tt&gt; to unmarshal individual values into a result slice that is provided by a caller.&#160;&lt;/p&gt;</comment>
                            <comment id="4612825" author="benji.rewis" created="Mon, 13 Jun 2022 21:15:04 +0000"  >&lt;p&gt;And let me know if that workaround with &lt;tt&gt;RunCommand&lt;/tt&gt; proves unusable for any reason (either through this ticket or another).&lt;/p&gt;</comment>
                            <comment id="4612820" author="benji.rewis" created="Mon, 13 Jun 2022 21:14:23 +0000"  >&lt;p&gt;Filed &lt;a href=&quot;https://jira.mongodb.org/browse/GODRIVER-2444&quot; title=&quot;Consider a DistinctCursor collection method&quot; class=&quot;issue-link&quot; data-issue-key=&quot;GODRIVER-2444&quot;&gt;GODRIVER-2444&lt;/a&gt; to track the addition of a method like &lt;tt&gt;DistinctCursor&lt;/tt&gt;. Feel free to track that ticket for the improvement. I agree that the current &lt;tt&gt;Distinct&lt;/tt&gt; method is confusing API and a new method pre-2.0 could be helpful. Thanks again for your improvement suggestion, &lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=petr.ivanov.s%40gmail.com&quot; class=&quot;user-hover&quot; rel=&quot;petr.ivanov.s@gmail.com&quot;&gt;petr.ivanov.s@gmail.com&lt;/a&gt;!&lt;/p&gt;</comment>
                            <comment id="4603944" author="petr.ivanov.s@gmail.com" created="Thu, 9 Jun 2022 08:40:05 +0000"  >&lt;p&gt;Thank you, Benji.&#160;&lt;/p&gt;

&lt;p&gt;The example seems all right. Can&apos;t say more until I use it in some way.&lt;/p&gt;

&lt;p&gt;I fully understand the issue with breaking change, but the current API seems awkward enough&#160; to warrant adding an alternative before v2, in my opinion. This seems better than dozens of users implementing the same thing differently, on their own.&#160;&lt;/p&gt;</comment>
                            <comment id="4589493" author="benji.rewis" created="Thu, 2 Jun 2022 12:24:58 +0000"  >&lt;p&gt;Thanks for your feature request, &lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=petr.ivanov.s%40gmail.com&quot; class=&quot;user-hover&quot; rel=&quot;petr.ivanov.s@gmail.com&quot;&gt;petr.ivanov.s@gmail.com&lt;/a&gt;! I agree it&apos;s odd that the &lt;tt&gt;All&lt;/tt&gt; method on &lt;tt&gt;Cursor&lt;/tt&gt; allows users to unmarshal to their own custom structs while the &lt;tt&gt;Distinct&lt;/tt&gt; method on &lt;tt&gt;Collection&lt;/tt&gt; unmarshals to []interface{} before returning. However, any changes to the return types of the &lt;tt&gt;Distinct&lt;/tt&gt; API are breaking changes and can&apos;t be implemented before a v2.x driver version.&lt;/p&gt;

&lt;p&gt;The best way to immediately resolve your problem is to use &lt;tt&gt;RunCommand&lt;/tt&gt;. Here&apos;s an example of how you might run &quot;distinct&quot; through &lt;tt&gt;RunCommand&lt;/tt&gt; and &lt;tt&gt;Decode&lt;/tt&gt; to your own custom struct representing the structure of the queried field&apos;s values.&lt;/p&gt;

&lt;p&gt;&lt;span class=&quot;nobr&quot;&gt;&lt;a href=&quot;https://jira.mongodb.org/secure/attachment/382635/382635_distinct_runCommand.go&quot; title=&quot;distinct_runCommand.go attached to GODRIVER-2426&quot;&gt;distinct_runCommand.go&lt;sup&gt;&lt;img class=&quot;rendericon&quot; src=&quot;https://jira.mongodb.org/images/icons/link_attachment_7.gif&quot; height=&quot;7&quot; width=&quot;7&quot; align=&quot;absmiddle&quot; alt=&quot;&quot; border=&quot;0&quot;/&gt;&lt;/sup&gt;&lt;/a&gt;&lt;/span&gt;&lt;/p&gt;

&lt;p&gt;As far as improvements to the driver, I&apos;ve created &lt;a href=&quot;https://jira.mongodb.org/browse/GODRIVER-2443&quot; title=&quot;Make Distinct return a decodable struct &amp;quot;[]any&amp;quot;&quot; class=&quot;issue-link&quot; data-issue-key=&quot;GODRIVER-2443&quot;&gt;GODRIVER-2443&lt;/a&gt; to track improving the &lt;tt&gt;Distinct&lt;/tt&gt; API in the v2.x driver and &lt;a href=&quot;https://jira.mongodb.org/browse/GODRIVER-2444&quot; title=&quot;Consider a DistinctCursor collection method&quot; class=&quot;issue-link&quot; data-issue-key=&quot;GODRIVER-2444&quot;&gt;GODRIVER-2444&lt;/a&gt; to track a proposal to add something like a &lt;tt&gt;DistinctCursor&lt;/tt&gt; function to the current v1.x driver that would return a &lt;tt&gt;Cursor&lt;/tt&gt; like &lt;tt&gt;Find&lt;/tt&gt; or &lt;tt&gt;Aggregate&lt;/tt&gt;.&lt;/p&gt;

&lt;p&gt;Let me know what you think and if that example is helpful.&lt;/p&gt;</comment>
                            <comment id="4567260" author="kevin.albertson" created="Mon, 23 May 2022 18:50:19 +0000"  >&lt;p&gt;Thank you for the report &lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=petr.ivanov.s%40gmail.com&quot; class=&quot;user-hover&quot; rel=&quot;petr.ivanov.s@gmail.com&quot;&gt;petr.ivanov.s@gmail.com&lt;/a&gt;. The description has been updated. We will look into this soon.&lt;/p&gt;</comment>
                            <comment id="4558469" author="petr.ivanov.s@gmail.com" created="Thu, 19 May 2022 06:41:08 +0000"  >&lt;p&gt;For some reason code blocks ended up malformed, and I seem to lack the privilege to fix it.&#160;&lt;/p&gt;</comment>
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