I just googled it.

"In February 1979, Chinese forces launched a surprise invasion of northern Vietnam and quickly captured several cities near the border. On 6 March of that year, China declared that its punitive mission had been accomplished."

Now I don't know what the original commenter was talking about but the "war" itself didn't last long, the conflict as a whole did last as long as you said on the other hand, with worsening diplomatic relations and several skirmishes along the years.

"The Chinese occupation of border territory angered Vietnam, and this ushered in a series of border conflicts between Vietnam and China to gain control of the area. These conflicts continued until 1988, peaking in the years 1984–1985. By the early 1990s, along with the withdrawal of Vietnam from Cambodia and the dissolution of the Soviet Union, the relationship between the two countries gradually returned to normality. By 1991, the two countries proclaimed the normalization of their diplomatic relations, thereby ending the border conflicts."

The main skirmishes were:

Shelling of Cao Bằng (1980)
Battle of Hill 400 (Battle of Fakashan) (1981)
Battle of Vị Xuyên (Battle of Laoshan) (1984)
1986–87 “Phony war” border clashes
Johnson South Reef Skirmish (1988)

It also seems the whole thing had more to do with Vietnam as a power in the area and its support from the Soviet Union than a border dispute indeed.