From 79a504a44cefa119f1ef8c0db28e7fa674aeaf32 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Skytt=C3=A4?= <ville.skytta@iki.fi>
Date: Mon, 7 Dec 2020 01:12:10 +0200
Subject: [PATCH] _variables: split out _variable_assignments, use in export

Closes https://github.com/scop/bash-completion/issues/457
---
 bash_completion     | 77 +++++++++++++++++++++++++++++----------------
 completions/export  |  5 +--
 test/t/test_grep.py | 10 ++++++
 3 files changed, 61 insertions(+), 31 deletions(-)

diff --git a/bash_completion b/bash_completion
index 2114ea05086..1a097417d72 100644
--- a/bash_completion
+++ b/bash_completion
@@ -679,37 +679,60 @@ _variables()
         COMPREPLY+=("$cur}")
         __ltrim_colon_completions "$cur"
         return 0
-    else
-        case ${prev-} in
-            TZ)
-                cur=/usr/share/zoneinfo/$cur
-                _filedir
-                for i in "${!COMPREPLY[@]}"; do
-                    if [[ ${COMPREPLY[i]} == *.tab ]]; then
-                        unset 'COMPREPLY[i]'
-                        continue
-                    elif [[ -d ${COMPREPLY[i]} ]]; then
-                        COMPREPLY[i]+=/
-                        compopt -o nospace
-                    fi
-                    COMPREPLY[i]=${COMPREPLY[i]#/usr/share/zoneinfo/}
-                done
-                return 0
-                ;;
-            TERM)
-                _terms
-                return 0
-                ;;
-            LANG | LC_*)
-                COMPREPLY=($(compgen -W '$(locale -a 2>/dev/null)' \
-                    -- "$cur"))
-                return 0
-                ;;
-        esac
     fi
     return 1
 }
 
+# Complete assignment of various known environment variables.
+# The word to be completed is expected to contain the entire
+# assignment, including the variable name and the "=". See related
+# parameters to _init_completion.
+#
+# @param  $1 variable assignment to be completed
+# @return True (0) if variable value completion was attempted,
+#         False (> 0) if not.
+_variable_assignments()
+{
+    local cur=${1-}
+
+    if [[ $cur =~ ^([A-Za-z_][A-Za-z0-9_]*)=(.*)$ ]]; then
+        prev=${BASH_REMATCH[1]}
+        cur=${BASH_REMATCH[2]}
+    else
+        return 1
+    fi
+
+    case $prev in
+        TZ)
+            cur=/usr/share/zoneinfo/$cur
+            _filedir
+            for i in "${!COMPREPLY[@]}"; do
+                if [[ ${COMPREPLY[i]} == *.tab ]]; then
+                    unset 'COMPREPLY[i]'
+                    continue
+                elif [[ -d ${COMPREPLY[i]} ]]; then
+                    COMPREPLY[i]+=/
+                    compopt -o nospace
+                fi
+                COMPREPLY[i]=${COMPREPLY[i]#/usr/share/zoneinfo/}
+            done
+            ;;
+        TERM)
+            _terms
+            ;;
+        LANG | LC_*)
+            COMPREPLY=($(compgen -W '$(locale -a 2>/dev/null)' \
+                -- "$cur"))
+            ;;
+        *)
+            _variables && return 0
+            _filedir
+            ;;
+    esac
+
+    return 0
+}
+
 # Initialize completion and deal with various general things: do file
 # and variable completion where appropriate, and adjust prev, words,
 # and cword as if no redirections exist so that completions do not
diff --git a/completions/export b/completions/export
index 8d823614aaf..9cf94277678 100644
--- a/completions/export
+++ b/completions/export
@@ -25,10 +25,7 @@ _export()
     done
 
     if [[ $cur == *=* ]]; then
-        local ocur=$cur oprev=$prev
-        prev=${cur%%=*} cur=${cur#*=}
-        _variables && return
-        cur=$ocur prev=$oprev
+        _variable_assignments $cur && return
     fi
 
     case $cur in
diff --git a/test/t/test_grep.py b/test/t/test_grep.py
index a249122eb12..10956b1f5e9 100644
--- a/test/t/test_grep.py
+++ b/test/t/test_grep.py
@@ -14,3 +14,13 @@ def test_2(self, completion):
         Not really a grep option, but tests _longopt.
         """
         assert completion == "foo foo.d/".split()
+
+    @pytest.mark.complete("grep TZ ", cwd="shared/default")
+    def test_no_variable_assignment_confusion(self, completion):
+        """
+        Test TZ doesn't trigger known variable value assignment completion.
+
+        Not really a grep specific, but good to test somewhere.
+        Refs https://github.com/scop/bash-completion/issues/457
+        """
+        assert "foo" in completion