Override C compiler for testing that no duplicate arguments are passed

Author: sergv

cabal-testsuite/PackageTests/PreProcess/TooManyCommandLineArgs/custom-cc

@@ -0,0 +1,72 @@
+#!/usr/bin/env bash
+
+# NB only check for duplicated -L or -I arguments because that’s the
+# primary source of duplication. Some minor duplicates can also occur,
+# like -Wl,--no-as-needed but there’s not too many of them yet to
+# cause command line overflow.
+
+# Quadratic algorithm because darwin CI doesn’t seem to have bash that
+# supports associative arrays.
+check_duplicate() {
+    local test_arg="$1"
+    local occurs="0"
+
+    if ! [[ "$test_arg" == -L* || "$test_arg" == -I* ]]; then
+        return 0
+    fi
+
+    shift
+    for tmp in "${@}"; do
+        if [[ "$tmp" == @* ]]; then
+            while IFS= read -d $'\n' -r arg ; do
+                if [[ "$arg" == "$test_arg" ]]; then
+                    occurs=$((occurs + 1))
+                fi
+            done <"${tmp#@}"
+        else
+            if [[ "$tmp" == "$test_arg" ]]; then
+                occurs=$((occurs + 1))
+            fi
+        fi
+    done
+
+    if [[ "$occurs" -gt 1 ]]; then
+        return 1
+    else
+        return 0
+    fi
+}
+
+i=1
+for x in "${@}"; do
+    if [[ "$x" == @* ]]; then
+        file=
+        while IFS= read -d $'\n' -r arg ; do
+            y="$arg"
+            if ! check_duplicate "$arg" "${@:$i}"; then
+                echo "Duplicate argument detected: '$y'"
+                echo "All args: ${@}"
+                exit 1
+            fi
+        done <"${x#@}"
+    else
+        if ! check_duplicate "$x" "${@:$i}"; then
+            echo "Duplicate argument detected: '$x'"
+            echo "All args: ${@}"
+            exit 1
+        fi
+    fi
+
+    i=$((i + 1))
+done
+
+if which cc >/dev/null 2>&1; then
+    cc -DNOERROR6 "${@}"
+elif which gcc >/dev/null 2>&1; then
+    gcc -DNOERROR6 "${@}"
+elif which clang >/dev/null 2>&1; then
+    clang -DNOERROR6 "${@}"
+else
+    echo "Cannot find C compiler" >&2
+    exit 1
+fi

cabal-testsuite/PackageTests/PreProcess/TooManyCommandLineArgs/setup.test.hs

@@ -87,9 +87,20 @@ main = cabalTest $ do
       libFlags =
         concatMap (\x -> ["--extra-lib-dirs", cwd </> x]) libDirs
 
+  let customCC = cwd </> "custom-cc"
+
   -- Parallel flag means output of this test is nondeterministic
   _<- recordMode DoNotRecord $
-    cabal "v2-build" $ ["-j", "my-toplevel:exe:my-executable"] ++ includeFlags ++ libFlags
+    cabal "v2-build" $
+      ["-j", "my-toplevel:exe:my-executable"]
+        -- Don’t validate absence of duplicates on Windows because
+        -- it’s too inconvenient to do in bat files. Let’s just
+        -- assume that deduplication will happen on Windows but
+        -- still try to run the test to see whether command-line
+        -- argument length limit is not hit.
+        ++ ["--with-gcc=" ++ customCC | not isWindows]
+        ++ includeFlags
+        ++ libFlags
   r <- withPlan $ runPlanExe' "my-toplevel" "my-executable" []
   assertOutputContains
     ("Result = " ++ show (42 + 55 + 10 * (55 + 10 * 55) + 3 * 55))