feat: reject mcpp add for packages not present in the index

Validate that the requested package exists in a configured index before
mutating mcpp.toml. If the package is not found, print an error and exit
without writing the dependency. Also propagate config-load failures.

Closes #305

Author: ZheFeng7110

src/pm/commands.cppm

@@ -14,6 +14,9 @@
 export module mcpp.pm.commands;
 
 import std;
+import mcpp.config;
+import mcpp.fetcher;
+import mcpp.fetcher.progress;
 import mcpp.manifest;            // kDefaultNamespace alias
 import mcpp.lockfile;             // load / write (still via shim)
 import mcpp.project;              // shared find_manifest_root
@@ -68,6 +71,24 @@ inline int cmd_add(const mcpplibs::cmdline::ParsedArgs& parsed) {
         return 2;
     }
 
+    // Validate package existence against the configured index before mutating
+    // mcpp.toml. A missing package is a hard error: we don't want to write an
+    // invalid dependency that only fails later during build.
+    {
+        auto cfg = mcpp::config::load_or_init(
+            /*quiet=*/false, mcpp::fetcher::make_bootstrap_progress_callback());
+        if (!cfg) {
+            mcpp::ui::error(cfg.error().message);
+            return 4;
+        }
+        mcpp::fetcher::Fetcher f(*cfg);
+        if (!f.read_xpkg_lua(ns, shortName)) {
+            mcpp::ui::error(std::format(
+                "package '{}' not found in any configured index", shortName));
+            return 2;
+        }
+    }
+
     std::ifstream in(manifestPath);
     std::stringstream ss; ss << in.rdbuf();
     std::string text = ss.str();

tests/e2e/12_add_command.sh

@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 # requires:
-# `mcpp add` modifies mcpp.toml [dependencies]. Dotted package selectors are
-# preserved in the single table; `ns:name` remains the explicit namespace form.
+# `mcpp add` modifies mcpp.toml [dependencies]. Default-namespace packages land
+# as bare keys under [dependencies]; `ns:name` (non-default ns) uses a subtable.
+# Non-existent packages are rejected before mcpp.toml is mutated.
 set -e
 
 TMP=$(mktemp -d)
@@ -13,38 +14,26 @@ cd "$TMP"
 "$MCPP" new myapp > /dev/null
 cd myapp
 
-# (1) Default-namespace dep: bare name → unquoted key under [dependencies].
-"$MCPP" add somedep@0.1.0 > /dev/null
+# (1) Default-namespace dep via `<ns>:<name>@<ver>` where ns is the default
+# (mcpplibs). Since 0.0.10+ default namespace is "mcpplibs", this lands as a
+# bare key under [dependencies], NOT in [dependencies.mcpplibs].
+"$MCPP" add mcpplibs:cmdline@0.0.1 > /dev/null
 grep -qE '^\[dependencies\]'        mcpp.toml || { cat mcpp.toml; echo "no [dependencies] section"; exit 1; }
-grep -qE '^somedep = "0\.1\.0"$'    mcpp.toml || { cat mcpp.toml; echo "somedep entry missing or quoted"; exit 1; }
-grep -qE '^"somedep"'               mcpp.toml && { cat mcpp.toml; echo "default-ns key should not be quoted"; exit 1; }
+grep -qE '^cmdline = "0\.0\.1"$'    mcpp.toml || { cat mcpp.toml; echo "cmdline entry missing or wrong version"; exit 1; }
+grep -qE '^"cmdline"'               mcpp.toml && { cat mcpp.toml; echo "default-ns key should not be quoted"; exit 1; }
 
 # (2) Second default-ns dep — append, do not duplicate the section header.
-"$MCPP" add another@0.2.0 > /dev/null
+"$MCPP" add mcpplibs:templates@0.0.1 > /dev/null
 header_count=$(grep -cE '^\[dependencies\]$' mcpp.toml)
 [[ "$header_count" == "1" ]] || { cat mcpp.toml; echo "[dependencies] header duplicated"; exit 1; }
-grep -qE '^another = "0\.2\.0"$' mcpp.toml || { cat mcpp.toml; echo "another not set"; exit 1; }
-
-# (3) Default-ns dep via `<ns>:<name>@<ver>` where ns is the default (mcpplibs).
-# Since 0.0.10+ default namespace is "mcpplibs", this lands as a bare key
-# under [dependencies], NOT in [dependencies.mcpplibs].
-"$MCPP" add mcpplibs:cmdline@0.0.2 > /dev/null
-grep -qE '^cmdline = "0\.0\.2"$' mcpp.toml || { cat mcpp.toml; echo "cmdline entry missing"; exit 1; }
-
-# (4) A second default-ns package — also goes under [dependencies].
-"$MCPP" add mcpplibs:templates@0.0.1 > /dev/null
-grep -qE '^templates = "0\.0\.1"$' mcpp.toml || { cat mcpp.toml; echo "templates entry missing"; exit 1; }
-
-# (5) Dotted selector input is preserved under the single [dependencies] table.
-"$MCPP" add acme.util@2.0.0 > /dev/null
-grep -qE '^acme\.util = "2\.0\.0"$' mcpp.toml || { cat mcpp.toml; echo "acme.util selector entry missing"; exit 1; }
+grep -qE '^templates = "0\.0\.1"$' mcpp.toml || { cat mcpp.toml; echo "templates not set"; exit 1; }
 
-# (6) Colon form remains explicit namespace syntax and uses a subtable.
+# (3) Colon form remains explicit namespace syntax and uses a subtable.
 "$MCPP" add compat:gtest@1.15.2 > /dev/null
 grep -qE '^\[dependencies\.compat\]$' mcpp.toml || { cat mcpp.toml; echo "missing [dependencies.compat] section"; exit 1; }
 grep -qE '^gtest = "1\.15\.2"$'        mcpp.toml || { cat mcpp.toml; echo "gtest entry missing"; exit 1; }
 
-# (7) Dotted remove can still clean the old subtable shape for compatibility.
+# (4) Dotted remove can still clean the old subtable shape for compatibility.
 cat >> mcpp.toml <<'EOF'
 
 [dependencies.legacy]
@@ -53,11 +42,17 @@ EOF
 "$MCPP" remove legacy.old > /dev/null
 ! grep -qE '^old = "0\.1\.0"$' mcpp.toml || { cat mcpp.toml; echo "legacy.old was not removed"; exit 1; }
 
-# (8) Reject missing version.
+# (5) Reject missing version.
 err=$("$MCPP" add bareword 2>&1) && { echo "expected error for missing version"; exit 1; }
 [[ "$err" == *"version required"* ]] || { echo "wrong error: $err"; exit 1; }
 
-# (9) Reject empty package name (e.g. `mcpp add :foo@1.0`).
+# (6) Reject empty package name (e.g. `mcpp add :foo@1.0`).
 err=$("$MCPP" add ":@1.0" 2>&1) && { echo "expected error for empty package name"; exit 1; }
 
+# (7) Reject non-existent package and do not mutate mcpp.toml.
+cp mcpp.toml mcpp.toml.before
+err=$("$MCPP" add definitely-not-a-real-package@9.9.9 2>&1) && { echo "expected error for missing package"; exit 1; }
+[[ "$err" == *"not found"* ]] || { echo "wrong error: $err"; exit 1; }
+diff -q mcpp.toml.before mcpp.toml || { cat mcpp.toml; echo "mcpp.toml mutated for missing package"; exit 1; }
+
 echo "OK"