API docs: indexer: do not include Go blank const/var identifiers (#164)

Fixes https://github.com/sourcegraph/sourcegraph/issues/22029

Signed-off-by: Stephen Gutekanst <[email protected]>

internal/indexer/documentation.go

@@ -369,7 +369,11 @@ func (d *docsIndexer) indexGenDecl(p *packages.Package, f *ast.File, node *ast.G
 		case *ast.ValueSpec:
 			// Variable or constant, potentially of the form `var x, y = 1, 2` - we emit each
 			// separately.
-			for i := range t.Names {
+			for i, name := range t.Names {
+				if name.Name == "_" {
+					// Not only is it not exported, it cannot be referenced outside this package at all.
+					continue
+				}
 				switch node.Tok {
 				case token.CONST:
 					constDocs := d.indexConstVar(p, t, i, "const", isTestFile)

internal/indexer/testdata/TestIndexer_documentation/testdata.golden

@@ -34,7 +34,6 @@ testdata is a small package containing sample Go source code used for testing th
   - [var BigVar](#github.com-sourcegraph-lsif-go-internal-testdata---BigVar)
   - [var VarBlock1](#github.com-sourcegraph-lsif-go-internal-testdata---VarBlock1)
   - [var VarBlock2](#github.com-sourcegraph-lsif-go-internal-testdata---VarBlock2)
-  - [var _](#github.com-sourcegraph-lsif-go-internal-testdata---_)
   - [var wg](#github.com-sourcegraph-lsif-go-internal-testdata---wg)
 - [Types](#github.com-sourcegraph-lsif-go-internal-testdata---type)
   - [type Embedded struct](#github.com-sourcegraph-lsif-go-internal-testdata---Embedded)
@@ -1083,101 +1082,6 @@ ZZZzz /,`.-'`'    -.  ;-;;,_
 ```
 It's sleeping! Some people write that as `sleeping` but Markdown isn't allowed in Go docstrings, right? right?! 
 
-#### <a name="github.com-sourcegraph-lsif-go-internal-testdata---_">var _</a>
-
-<details><summary>hover</summary>
-
-> ```go
-> var _ invalid type
-> ```
-> 
-> ---
-> 
-> Yeah this is some Go magic incantation which is common. 
-> 
-> ```
->  ,_     _
->  |\\_,-~/
->  / _  _ |    ,--.
-> (  @  @ )   / ,-'
->  \  _T_/-._( (
-> /         `. \
-> |         _  \ |
-> \ \ ,  /      |
->  || |-_\__   /
-> ((_/`(____,-'
-> 
-> ```
-
-</details>
-
-<details><summary>definitions</summary>
-
-```json
-[
- {
-  "Document": "/child_symbols.go",
-  "Ranges": [
-   {
-    "start": {
-     "line": 116,
-     "character": 4
-    },
-    "end": {
-     "line": 116,
-     "character": 5
-    }
-   }
-  ]
- }
-]
-```
-
-</details>
-
-<details><summary>references</summary>
-
-```json
-[
- {
-  "Document": "/child_symbols.go",
-  "Ranges": [
-   {
-    "start": {
-     "line": 116,
-     "character": 4
-    },
-    "end": {
-     "line": 116,
-     "character": 5
-    }
-   }
-  ]
- }
-]
-```
-
-</details>
-
-```Go
-var _ = Interface(&Struct{})
-```
-
-Yeah this is some Go magic incantation which is common. 
-
-```
- ,_     _
- |\\_,-~/
- / _  _ |    ,--.
-(  @  @ )   / ,-'
- \  _T_/-._( (
-/         `. \
-|         _  \ |
-\ \ ,  /      |
- || |-_\__   /
-((_/`(____,-'
-
-```
 #### <a name="github.com-sourcegraph-lsif-go-internal-testdata---wg">var wg</a>
 
 <details><summary>hover</summary>