go-mod-discovery/oe-go-mod-fetcher: add GO_MOD_VCS_EXCLUDE for deleted repos

Some upstream Go module repositories get deleted from GitHub (e.g.,
github.com/vtolstov/go-ioctl). While the Go module proxy still serves
cached archives, VCS mode cannot git clone a deleted repo. This causes
both do_fetch failures and generator verification failures.

Add GO_MOD_VCS_EXCLUDE recipe variable (space-separated module path
prefixes) and corresponding --exclude-module CLI flag. Excluded modules
are filtered out before verification and SRC_URI generation. Recipes
must provide a gomod:// SRC_URI entry for excluded modules as fallback.

Usage in recipe:
  SRC_URI += "gomod://example.com/deleted-repo;version=v1.0.0;sha256sum=..."
  GO_MOD_VCS_EXCLUDE = "example.com/deleted-repo"

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

2 files changed, 32 insertions, 2 deletions

diff --git a/classes/go-mod-discovery.bbclass b/classes/go-mod-discovery.bbclass
index d41d70a5..39cc38da 100644
--- a/classes/go-mod-discovery.bbclass
+++ b/classes/go-mod-discovery.bbclass
@@ -122,6 +122,11 @@ GO_MOD_DISCOVERY_RECIPEDIR ?= "${FILE_DIRNAME}"
 # Usage: GO_MOD_DISCOVERY_SKIP_VERIFY = "1" in local.conf or recipe
 GO_MOD_DISCOVERY_SKIP_VERIFY ?= ""
 
+# Modules to exclude from git:// generation (space-separated prefixes)
+# Excluded modules must be fetched via gomod:// in the recipe's SRC_URI
+# Usage: GO_MOD_VCS_EXCLUDE = "github.com/vtolstov/go-ioctl"
+GO_MOD_VCS_EXCLUDE ?= ""
+
 # Empty default for TAGS if not set by recipe (avoids undefined variable errors)
 TAGS ?= ""
 
@@ -396,12 +401,18 @@ Or run 'bitbake ${PN} -c show_upgrade_commands' to see manual options."
         SKIP_VERIFY_FLAG="--skip-verify"
     fi
 
+    EXCLUDE_FLAGS=""
+    for mod in ${GO_MOD_VCS_EXCLUDE}; do
+        EXCLUDE_FLAGS="${EXCLUDE_FLAGS} --exclude-module ${mod}"
+    done
+
     python3 "${FETCHER_SCRIPT}" \
         --discovered-modules "${GO_MOD_DISCOVERY_MODULES_JSON}" \
         --git-repo "${GO_MOD_DISCOVERY_GIT_REPO}" \
         --git-ref "${GO_MOD_DISCOVERY_GIT_REF}" \
         --recipedir "${GO_MOD_DISCOVERY_RECIPEDIR}" \
-        ${SKIP_VERIFY_FLAG}
+        ${SKIP_VERIFY_FLAG} \
+        ${EXCLUDE_FLAGS}
 
     if [ $? -eq 0 ]; then
         echo ""
diff --git a/scripts/oe-go-mod-fetcher.py b/scripts/oe-go-mod-fetcher.py
index 5c866928..af8cbb03 100755
--- a/scripts/oe-go-mod-fetcher.py
+++ b/scripts/oe-go-mod-fetcher.py
@@ -2079,6 +2079,7 @@ def _execute(args: argparse.Namespace) -> int:
         debug_limit=debug_limit,
         skip_verify=args.skip_verify,
         verify_jobs=args.verify_jobs,
+        exclude_modules=args.exclude_module,
     )
 
     if success:
@@ -3869,7 +3870,7 @@ def discover_modules(source_dir: Path, gomodcache: Optional[str] = None) -> List
 def generate_recipe(modules: List[Dict], source_dir: Path, output_dir: Optional[Path],
                    git_repo: str, git_ref: str, validate_only: bool = False,
                    debug_limit: Optional[int] = None, skip_verify: bool = False,
-                   verify_jobs: int = 10) -> bool:
+                   verify_jobs: int = 10, exclude_modules: Optional[List[str]] = None) -> bool:
     """
     Phase 2: Recipe Generation
 
@@ -3897,6 +3898,17 @@ def generate_recipe(modules: List[Dict], source_dir: Path, output_dir: Optional[
 
     unresolved_commits: List[Tuple[str, str, str, str, str]] = []
 
+    # Filter out excluded modules (e.g., deleted upstream repos that must use gomod://)
+    if exclude_modules:
+        before_count = len(modules)
+        excluded_prefixes = [e.strip() for e in exclude_modules]
+        modules = [m for m in modules if not any(
+            m.get('module_path', '').startswith(prefix) for prefix in excluded_prefixes
+        )]
+        excluded_count = before_count - len(modules)
+        if excluded_count:
+            print(f"\n⚙️  Excluded {excluded_count} modules matching: {', '.join(excluded_prefixes)}")
+
     total_modules = len(modules)
     if debug_limit is not None:
         print(f"\n⚙️  Debug limit active: validating first {debug_limit} modules (total list size {total_modules})")
@@ -4518,6 +4530,13 @@ Examples:
     )
 
     parser.add_argument(
+        "--exclude-module",
+        metavar="PREFIX",
+        action="append",
+        help="Exclude modules matching PREFIX from git:// generation (use gomod:// in recipe instead)"
+    )
+
+    parser.add_argument(
         "--version",
         action="version",
         version=f"%(prog)s {VERSION}"