fix(gomod): skip placeholder pseudo versions (#41521)

As a follow-up to #41517, when we have a placeholder pseudo version, we
attempt to look up updates for the module.

However, because these are handled by a `replace` directive, there's no
point attempting to look them up.

Especially, as noted in #41517, this could be a non-public module, so
the lookup will fail unnecessarily.

Co-authored-by: Claude Sonnet 4.5 <jamie.tanna+github-copilot@mend.io>

Author: jamietanna

lib/modules/manager/gomod/extract.spec.ts

@@ -348,4 +348,99 @@ describe('modules/manager/gomod/extract', () => {
     const res = extractPackageFile(goMod);
     expect(res).toBeNull();
   });
+
+  it('marks placeholder pseudo versions with skipReason invalid-version', () => {
+    const goMod = codeBlock`
+        module github.com/renovate-tests/gomod
+        go 1.19
+        require (
+          github.com/foo/bar v1.2.3
+          github.com/baz/qux v0.0.0-00010101000000-000000000000
+          github.com/example/local v0.0.0-00010101000000-000000000000 // indirect
+          github.com/non/placeholder v1.2.4-0.20230101120000-abcdef123456
+          monorepo v0.0.0-00010101000000-000000000000
+        )
+      `;
+    const res = extractPackageFile(goMod);
+    expect(res).toEqual({
+      deps: [
+        {
+          managerData: {
+            lineNumber: 1,
+          },
+          depName: 'go',
+          depType: 'golang',
+          currentValue: '1.19',
+          datasource: 'golang-version',
+          versioning: 'go-mod-directive',
+        },
+        {
+          managerData: {
+            lineNumber: 3,
+            multiLine: true,
+          },
+          depName: 'github.com/foo/bar',
+          depType: 'require',
+          currentValue: 'v1.2.3',
+          datasource: 'go',
+        },
+        {
+          managerData: {
+            lineNumber: 4,
+            multiLine: true,
+          },
+          depName: 'github.com/baz/qux',
+          depType: 'require',
+          currentValue: 'v0.0.0-00010101000000-000000000000',
+          datasource: 'go',
+          skipReason: 'invalid-version',
+          currentDigest: '000000000000',
+          digestOneAndOnly: true,
+          versioning: 'loose',
+        },
+        {
+          managerData: {
+            lineNumber: 5,
+            multiLine: true,
+          },
+          depName: 'github.com/example/local',
+          depType: 'indirect',
+          currentValue: 'v0.0.0-00010101000000-000000000000',
+          datasource: 'go',
+          skipReason: 'invalid-version',
+          enabled: false,
+          currentDigest: '000000000000',
+          digestOneAndOnly: true,
+          versioning: 'loose',
+        },
+        {
+          managerData: {
+            lineNumber: 6,
+            multiLine: true,
+          },
+          depName: 'github.com/non/placeholder',
+          depType: 'require',
+          currentValue: 'v1.2.4-0.20230101120000-abcdef123456',
+          datasource: 'go',
+          currentDigest: 'abcdef123456',
+          digestOneAndOnly: true,
+          versioning: 'loose',
+        },
+        {
+          managerData: {
+            lineNumber: 7,
+            multiLine: true,
+          },
+          depName: 'monorepo',
+          depType: 'require',
+          currentValue: 'v0.0.0-00010101000000-000000000000',
+          datasource: 'go',
+          currentDigest: '000000000000',
+          digestOneAndOnly: true,
+          versioning: 'loose',
+          skipReason: 'invalid-version',
+        },
+      ],
+    });
+  });
 });

lib/modules/manager/gomod/line-parser.spec.ts

@@ -80,6 +80,21 @@ describe('modules/manager/gomod/line-parser', () => {
     });
   });
 
+  it('should parse require definition with placeholder pseudo-version', () => {
+    const line = 'require foo/foo v0.0.0-00010101000000-000000000000';
+    const res = parseLine(line);
+    expect(res).toStrictEqual({
+      currentDigest: '000000000000',
+      currentValue: 'v0.0.0-00010101000000-000000000000',
+      datasource: 'go',
+      depName: 'foo/foo',
+      depType: 'require',
+      digestOneAndOnly: true,
+      skipReason: 'invalid-version',
+      versioning: 'loose',
+    });
+  });
+
   it('should parse require multi-line', () => {
     const line = '        foo/foo v1.2';
     const res = parseLine(line);
@@ -250,6 +265,22 @@ describe('modules/manager/gomod/line-parser', () => {
     });
   });
 
+  it('should parse replace definition with placeholder pseudo-version', () => {
+    const line =
+      'replace foo/foo => bar/bar v0.0.0-00010101000000-000000000000';
+    const res = parseLine(line);
+    expect(res).toStrictEqual({
+      currentDigest: '000000000000',
+      currentValue: 'v0.0.0-00010101000000-000000000000',
+      datasource: 'go',
+      depName: 'bar/bar',
+      depType: 'replace',
+      digestOneAndOnly: true,
+      skipReason: 'invalid-version',
+      versioning: 'loose',
+    });
+  });
+
   it('should parse replace indirect definition', () => {
     const line = 'replace foo/foo => bar/bar v1.2 // indirect';
     const res = parseLine(line);

lib/modules/manager/gomod/line-parser.ts

@@ -29,11 +29,17 @@ const toolchainVersionRegex = regEx(/^\s*toolchain\s+go(?<version>[^\s]+)\s*$/);
 
 const pseudoVersionRegex = regEx(GoDatasource.pversionRegexp);
 
+const placeholderPseudoVersion = 'v0.0.0-00010101000000-000000000000';
+
 function extractDigest(input: string): string | undefined {
   const match = pseudoVersionRegex.exec(input);
   return match?.groups?.digest;
 }
 
+function isPlaceholderPseudoVersion(version: string): boolean {
+  return version === placeholderPseudoVersion;
+}
+
 export function parseLine(input: string): PackageDependency | null {
   const goVersionMatches = goVersionRegex.exec(input)?.groups;
   if (goVersionMatches) {
@@ -91,6 +97,9 @@ export function parseLine(input: string): PackageDependency | null {
         dep.currentDigest = digest;
         dep.digestOneAndOnly = true;
         dep.versioning = 'loose';
+        if (isPlaceholderPseudoVersion(currentValue)) {
+          dep.skipReason = 'invalid-version';
+        }
       }
     } else {
       dep.skipReason = 'invalid-version';
@@ -132,6 +141,9 @@ export function parseLine(input: string): PackageDependency | null {
         dep.currentDigest = digest;
         dep.digestOneAndOnly = true;
         dep.versioning = 'loose';
+        if (isPlaceholderPseudoVersion(currentValue)) {
+          dep.skipReason = 'invalid-version';
+        }
       }
     } else if (currentValue) {
       dep.skipReason = 'invalid-version';