support: fix flake8 error E741 ambiguous variable name

A recent update of flake8 in CI introduced a new check E741. It
basically checks that variables are at least 3 characters long. Up to
now, however, we have used shorter names in some places - all of them
turn out to be "l" for a line of text.

Replace all those "l" variables with "line".

Fixes: https://gitlab.com/buildroot.org/buildroot/-/jobs/1687009829
partially:
support/scripts/boot-qemu-image.py:47:21: E741 ambiguous variable name 'l'
support/scripts/check-dotconfig.py:20:38: E741 ambiguous variable name 'l'
support/scripts/size-stats:76:13: E741 ambiguous variable name 'l'
support/testing/tests/core/test_bad_arch.py:17:32: E741 ambiguous variable name 'l'
support/testing/tests/package/test_python_treq.py:10:30: E741 ambiguous variable name 'l'
support/testing/tests/toolchain/test_external.py:30:42: E741 ambiguous variable name 'l'

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

support/scripts/boot-qemu-image.py

@@ -43,9 +43,9 @@ def main():
         # In this case, spawn above will succeed at starting the wrapper
         # start-qemu.sh, but that one will fail (exit with 127) in such
         # a situation.
-        exit = [int(l.split(' ')[1])
+        exit = [int(line.split(' ')[1])
-                for l in e.value.splitlines()
+                for line in e.value.splitlines()
-                if l.startswith('exitstatus: ')]
+                if line.startswith('exitstatus: ')]
         if len(exit) and exit[0] == 127:
             print('qemu-start.sh could not find the qemu binary')
             sys.exit(0)

support/scripts/check-dotconfig.py

@@ -17,7 +17,7 @@ def main():
 
     # strip() to get rid of trailing \n
     with open(configfile) as configf:
-        configlines = [l.strip() for l in configf.readlines()]
+        configlines = [line.strip() for line in configf.readlines()]
 
     defconfiglines = []
     with open(defconfig) as defconfigf:

support/scripts/size-stats

@@ -73,8 +73,8 @@ def add_file(filesdict, relpath, abspath, pkg):
 def build_package_dict(builddir):
     filesdict = {}
     with open(os.path.join(builddir, "build", "packages-file-list.txt")) as f:
-        for l in f.readlines():
+        for line in f.readlines():
-            pkg, fpath = l.split(",", 1)
+            pkg, fpath = line.split(",", 1)
             # remove the initial './' in each file path
             fpath = fpath.strip()[2:]
             fullpath = os.path.join(builddir, "target", fpath)

support/testing/tests/core/test_bad_arch.py

@@ -14,5 +14,5 @@ class DetectBadArchTest(infra.basetest.BRConfigTest):
         if logf_path:
             s = 'ERROR: architecture for "/usr/bin/foo" is'
             with open(logf_path, "r") as f:
-                lines = [l for l in f.readlines() if l.startswith(s)]
+                lines = [line for line in f.readlines() if line.startswith(s)]
             self.assertEqual(len(lines), 1)

support/testing/tests/package/test_python_treq.py

@@ -7,7 +7,7 @@ class TestPythonTreq(TestPythonPackageBase):
     def run_sample_scripts(self):
         cmd = self.interpreter + " sample_python_treq.py"
         output, exit_code = self.emulator.run(cmd, timeout=20)
-        refuse_msgs = [1 for l in output if "Connection refused" in l]
+        refuse_msgs = [1 for line in output if "Connection refused" in line]
         self.assertGreater(sum(refuse_msgs), 0)
         self.assertEqual(exit_code, 0)
 

support/testing/tests/toolchain/test_external.py

@@ -27,7 +27,7 @@ class TestExternalToolchain(infra.basetest.BRTest):
             self.assertFalse(has_broken_links(path))
 
         with open(os.path.join(self.builddir, ".config"), 'r') as configf:
-            configlines = [l.strip() for l in configf.readlines()]
+            configlines = [line.strip() for line in configf.readlines()]
 
         if "BR2_BINFMT_ELF=y" in configlines:
             interp = infra.get_elf_prog_interpreter(self.builddir,