From c3158d8126e6773c0fee11b54ca86bd464e69ae9 Mon Sep 17 00:00:00 2001
From: Russell Keith-Magee <russell@keith-magee.com>
Date: Sun, 28 Jun 2020 09:42:02 +0800
Subject: [PATCH] Fixed #397 -- If Xcode command line tools are active, warn
 the user.

---
 changes/397.bugfix.rst                        |  1 +
 src/briefcase/integrations/xcode.py           | 27 ++++++++++----
 .../xcode/test_ensure_xcode_is_installed.py   | 37 ++++++++++++++++++-
 3 files changed, 56 insertions(+), 9 deletions(-)
 create mode 100644 changes/397.bugfix.rst

diff --git a/changes/397.bugfix.rst b/changes/397.bugfix.rst
new file mode 100644
index 000000000..ae513cae6
--- /dev/null
+++ b/changes/397.bugfix.rst
@@ -0,0 +1 @@
+iOS builds will now warn if the Xcode command line tools are the active.
diff --git a/src/briefcase/integrations/xcode.py b/src/briefcase/integrations/xcode.py
index 11feebed3..7c123dc93 100644
--- a/src/briefcase/integrations/xcode.py
+++ b/src/briefcase/integrations/xcode.py
@@ -148,6 +148,7 @@ def ensure_xcode_is_installed(
     try:
         output = command.subprocess.check_output(
             ['xcodebuild', '-version'],
+            stderr=subprocess.STDOUT,
             universal_newlines=True
         )
 
@@ -198,16 +199,28 @@ def ensure_xcode_is_installed(
 *************************************************************************
 """)
 
-    except subprocess.CalledProcessError:
-        raise BriefcaseCommandError("""
-Xcode is not installed.
+    except subprocess.CalledProcessError as e:
+        if " is a command line tools instance" in e.output:
+            raise BriefcaseCommandError("""
+Xcode is installed, but the active developer directory is a
+command line tools instance. To make XCode the active developer
+directory, run:
 
-You should be shown a dialog prompting you to install Xcode and the
-command line tools. Select "Get Xcode" to install Xcode from the app store.
+    $ sudo xcode-select -switch /Applications/Xcode.app
 
-You can install Xcode from the macOS App Store.
+and then re-run Briefcase.
+""")
+        else:
+            raise BriefcaseCommandError("""
+The Xcode install appears to exist, but Briefcase was unable to
+determine the current Xcode version. Running:
 
-Re-run Briefcase once that installation is complete.
+    $ xcodebuild -version
+
+should return the current Xcode version, but it raised an error.
+
+You may need to re-install Xcode. Re-run Briefcase once that
+installation is complete.
 """)
 
 
diff --git a/tests/integrations/xcode/test_ensure_xcode_is_installed.py b/tests/integrations/xcode/test_ensure_xcode_is_installed.py
index ba379cf23..b4d0272c3 100644
--- a/tests/integrations/xcode/test_ensure_xcode_is_installed.py
+++ b/tests/integrations/xcode/test_ensure_xcode_is_installed.py
@@ -34,20 +34,49 @@ def test_not_installed(tmp_path):
     command.subprocess.check_output.assert_not_called()
 
 
-def test_exists_but_not_installed(xcode):
+def test_exists_but_command_line_tools_selected(xcode):
+    "If the Xcode folder exists, but cmd-line tools are selected, raise an error."
+    command = mock.MagicMock()
+    command.subprocess.check_output.side_effect = subprocess.CalledProcessError(
+        cmd=['xcodebuild', '-version'],
+        returncode=1
+    )
+    command.subprocess.check_output.side_effect.output = (
+        "xcode-select: error: tool 'xcodebuild' requires Xcode, but "
+        "active developer directory '/Library/Developer/CommandLineTools' "
+        "is a command line tools instance\n"
+    )
+
+    with pytest.raises(BriefcaseCommandError, match=r"xcode-select -switch"):
+        ensure_xcode_is_installed(command, xcode_location=xcode)
+
+    # xcode-select was invoked
+    command.subprocess.check_output.assert_called_once_with(
+        ['xcodebuild', '-version'],
+        stderr=subprocess.STDOUT,
+        universal_newlines=True,
+    )
+
+
+def test_exists_but_corrupted(xcode):
     "If the Xcode folder exists, but xcodebuild breaks, raise an error."
     command = mock.MagicMock()
     command.subprocess.check_output.side_effect = subprocess.CalledProcessError(
         cmd=['xcodebuild', '-version'],
         returncode=1
     )
+    command.subprocess.check_output.side_effect.output = "Badness occurred."
 
-    with pytest.raises(BriefcaseCommandError):
+    with pytest.raises(
+        BriefcaseCommandError,
+        match=r"should return the current Xcode version"
+    ):
         ensure_xcode_is_installed(command, xcode_location=xcode)
 
     # xcode-select was invoked
     command.subprocess.check_output.assert_called_once_with(
         ['xcodebuild', '-version'],
+        stderr=subprocess.STDOUT,
         universal_newlines=True,
     )
 
@@ -63,6 +92,7 @@ def test_installed_no_minimum_version(xcode):
     # xcode-select was invoked
     command.subprocess.check_output.assert_called_once_with(
         ['xcodebuild', '-version'],
+        stderr=subprocess.STDOUT,
         universal_newlines=True,
     )
 
@@ -122,6 +152,7 @@ def test_installed_with_minimum_version_success(min_version, version, capsys, xc
     # xcode-select was invoked
     command.subprocess.check_output.assert_called_once_with(
         ['xcodebuild', '-version'],
+        stderr=subprocess.STDOUT,
         universal_newlines=True,
     )
 
@@ -160,6 +191,7 @@ def test_installed_with_minimum_version_failure(min_version, version, xcode):
     # xcode-select was invoked
     command.subprocess.check_output.assert_called_once_with(
         ['xcodebuild', '-version'],
+        stderr=subprocess.STDOUT,
         universal_newlines=True,
     )
 
@@ -179,6 +211,7 @@ def test_unexpected_version_output(capsys, xcode):
     # xcode-select was invoked
     command.subprocess.check_output.assert_called_once_with(
         ['xcodebuild', '-version'],
+        stderr=subprocess.STDOUT,
         universal_newlines=True,
     )