From 112a7d8b9b819c38884527ada71539f3a9b745d7 Mon Sep 17 00:00:00 2001
From: Gandalf- <austin.voecks@gmail.com>
Date: Fri, 11 Jan 2019 10:17:44 -0800
Subject: [PATCH] Issue 1330 unsupported echo flags

Issue https://github.com/koalaman/shellcheck/issues/1330

Addresses false positives when quoted arguments to echo begin with what
looks like a flag. Now, warn only when the first argument is a
recognized echo flag when flags are unsupported.
---
 src/ShellCheck/Checks/ShellSupport.hs | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/src/ShellCheck/Checks/ShellSupport.hs b/src/ShellCheck/Checks/ShellSupport.hs
index 8f55b3c..40397af 100644
--- a/src/ShellCheck/Checks/ShellSupport.hs
+++ b/src/ShellCheck/Checks/ShellSupport.hs
@@ -152,6 +152,10 @@ prop_checkBashisms69 = verifyNot checkBashisms "#!/bin/sh\numask -S"
 prop_checkBashisms70 = verify checkBashisms "#!/bin/sh\ntrap -l"
 prop_checkBashisms71 = verify checkBashisms "#!/bin/sh\ntype -a ls"
 prop_checkBashisms72 = verifyNot checkBashisms "#!/bin/sh\ntype ls"
+prop_checkBashisms73 = verifyNot checkBashisms "#!/bin/sh\necho \"-n foo\""
+prop_checkBashisms74 = verifyNot checkBashisms "#!/bin/sh\necho \"-ne foo\""
+prop_checkBashisms75 = verifyNot checkBashisms "#!/bin/sh\necho -Q foo"
+prop_checkBashisms76 = verify checkBashisms "#!/bin/sh\necho -ne foo"
 checkBashisms = ForShell [Sh, Dash] $ \t -> do
     params <- ask
     kludge params t
@@ -238,15 +242,17 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
         warnMsg id "`<file` to read files is"
 
     bashism t@(T_SimpleCommand _ _ (cmd:arg:_))
-        | t `isCommand` "echo" && "-" `isPrefixOf` argString =
-            unless ("--" `isPrefixOf` argString) $ -- echo "-----"
-                if isDash
-                then
-                    when (argString /= "-n") $
-                        warnMsg (getId arg) "echo flags besides -n"
-                else
-                    warnMsg (getId arg) "echo flags are"
-      where argString = concat $ oversimplify arg
+        | t `isCommand` "echo" && argString `matches` flagRegex =
+            if isDash
+            then
+                when (argString /= "-n") $
+                    warnMsg (getId arg) "echo flags besides -n"
+            else
+                warnMsg (getId arg) "echo flags are"
+      where
+          argString = concat $ oversimplify arg
+          flagRegex = mkRegex "^-[eEsn]+$"
+
     bashism t@(T_SimpleCommand _ _ (cmd:arg:_))
         | t `isCommand` "exec" && "-" `isPrefixOf` concat (oversimplify arg) =
             warnMsg (getId arg) "exec flags are"